New York Cork Report

Will Climate Change Help the Finger Lakes Wine Industry? Here's Why it Might

By Evan Dawson, Finger Lakes Editor

I read an article this week that has me thinking about climate and winter and the Finger Lakes wine industry. We head into Christmas weekend on pace for the second-lowest snow total ever -- as in, ever recorded in more than 125 years -- along with one of the top three warmest Decembers. So with my brain already stuck on the subject of unusual weather, I was interested to hear the take of the wine and science communities on how climate change has impacted other major wine regions.

This piece comes from John McQuaid, a journalist focusing on science and the environment and, evidently, wine. McQuaid points to a handful of new studies and scientific findings that indicate the globe is slowly warming, and he zeroes in on the impact on wine regions:

• The average growing-season temperature in 27 prime wine-producing regions around the world has risen 2.3 degrees Farenheit in the last half-century
• That temperature increase nearly doubles in Spain, Portugal, southern France, parts of California, and Washington State.

This runs parallel to some of the conversations I've had this year with Alan Lakso, a professor (and a brilliant one) at Cornell who has done extensive work in understanding how climatological forces impact the Finger Lakes region. Our discussions centered on the following observations:

• In the Finger Lakes, the average summer highs are not markedly rising, but the average winter lows are
• This tends to lead to a longer growing season, because spring thaws tend to happen earlier
• Even though deep freezes are less common, vines are still at risk because temperatures are more likely to swing wildly 

This last point is significant. The often-quoted magic number is -10 degree Farenheit; that's the threshold when vinifera vines will start to die with any extended exposure. But Lakso explained to me that vines can be similarly shocked (injured or even killed) when the temperature hits zero... if the temperature has fallen, say, 30 to even 50 degrees in a single day or two. The vines would not be accustomed to the cold, and without a little practice and protection (and often without the warmth of a snow pack), bad things can happen.

The ideal scenario is a vintage like 2010, which saw budbreak in April. Growers were nervous; they know that an April budbreak leaves buds vulnerable to debilitating frosts. But for the most part, that didn't happen in 2010, and the result was a historically long growing season that gave wine producers plenty of options on ripeness, style and picking schedules.

Notice I didn't say that 2010 was "hot." It was simply long, consistently warm. And I think that distinction is where McQuaid might be tripping up, as he puts forward a bit of hyperbole in his analysis. He cites a study indicating that Bordeaux is seeing average temperatures rise too far for white varieties to thrive. By 2049, "No more Sauvignon Blanc" in Bordeaux, McQuaid writes.

The data hasn't convinced me that the future is so severe and so close to our doorstep, and longer growing seasons don't always equal hotter growing seasons. But certainly McQuaid makes another valuable point: Longer growing seasons have opened up new opportunities in cool climate wine regions. He mentions Long Island and Canada's Prince Edward County as examples. Certainly the Finger Lakes is another. 

But before we celebrate, we must remember that the cooler a wine region's climate, the more susceptible it is to vintage variation. Even as we experience longer seasons, there is extreme variability. The glorious 2010 vintage was preceded by 2009, when Finger Lakes winemakers knew by July that Bordeaux red varieties were bound to struggle. And the 2010 vintage was followed by a winter that saw a few of those vertiginous drops in temperature; some Keuka Lake growers experienced serious winter injury as a result. 

It's too early to draw conclusions regarding what climate change means for wine regions and wine lovers. But by now there is enough data to know that New York State is well positioned for a long, successful winemaking future. After all, the best wines are already earning the world's attention. Longer growing seasons and more options can only broaden the arsenal. 

Some Finger Lakes Wineries Favor Synthetic Corks for Their Best Wines; Should They?

By Evan Dawson, Managing Editor, and Tom Mansell, Science Editor

Serious wine consumers are not, generally speaking, fans of synthetic cork. Most recoil at the sight of a plastic cork being pulled from a bottle they had otherwise been excited to open. Is this bias unfair? Maybe. Companies are working to improve the quality of synthetic corks. We'll get to that in a bit. But there's no denying that synthetic corks make a clear statement to the serious consumer, whether intended or not.

"Cheap," said one of the many tasters on the evening of the recent Finger Lakes Riesling Hour. The inaugural riesling launch event led to coordinated tastings around the state and beyond. In Rochester, we had a packed room and it wasn't long before someone noticed that several 2010 Finger Lakes rieslings were closed with synthetic corks. In particular, the synthetic closures on Dr. Konstantin Frank and Rooster Hill stood out at our tasting. We're told that a few other Finger Lakes rieslings opened that night were also closed with synthetic.

"I hate them," says Leo Frokic, a downstate wine aficionado. "They let oxygen in. Would never buy anything worth aging that was sealed with synthetic corks."

"If I see plastic, I worry," says Loren Sonkin, owner of Sonkin Cellars, which makes California syrah blends. "I won't buy wine to age if I know it is in plastic. I am disappointed in the winery and left wondering why."

Synthetic closures are mostly made from petroleum-derived polymeric materials. Essentially, they are plastic. And the types of plastic that synthetics are made of are not good oxygen barriers.  While wine aging is a complex chemical phenomenon, it’s generally agreed that oxygen plays an important role in the evolution of a wine in the bottle. Studies consistently show that synthetic closures have a higher oxygen transfer rate (OTR) than cork or screwcap closures. In general, cork, being a natural product, shows the most variation in OTR, while screwcaps are consistently the lowest and synthetics are consistently higher than cork.

So let's attempt to answer Sonkin’s question: Why are some of the top Finger Lakes wineries using synthetic corks to close their rieslings? We posed that question to Fred Frank, owner of Dr. Konstantin Frank Vinifera Wine Cellars on Keuka Lake.

Cost

Frank explained that the price of each individual Dr. Frank bottling determines their use of closure. Their most expensive wines are closed with high-grade natural corks. "In our mid-priced wines, we use synthetic corks from Syncor," Frank explained. "These corks are imported from Germany and the manufacturer claims they perform the best in testing run by a university. In our lower-priced wines, we use synthetic corks from Nomacorc."

Frank's decision to base the closure on the wine's price leads to a potential problem. Dr. Frank's 2008 Meritage, for example, sells for twice the price of the 2010 Semi-Dry Riesling. But history suggests that the riesling will outlast the Meritage in your cellar.

Synthetic corks offer a significant potential savings, but there are levels of quality with each kind of cork. Natural corks run from about $0.20 apiece up to roughly a dollar. Most wineries tell us that they use natural corks that cost either $0.26 apiece or just about twice that. Synthetic corks can come in around a dime apiece, but the price can rise to the natural cork level for the new, higher-end versions. A winery that produces 10,000 cases of wine annually could save $36,000 by switching from higher-end natural cork to lower-end synthetic cork. Would the wine suffer? Over the long term, almost certainly yes. But again, winery owners know that most consumers don't have a long term.

Closure contamination

Last year, Rooster Hill owner Amy Hoffman explained why she chooses synthetic cork instead of natural cork for Rooster Hill's rieslings.

"(Winemaker) Barry Tortolone and I have discussed this at length," Hoffman said. "The biggest reason is to ensure corked wines are not poured in restaurants that typically don't have good trained staff that may recognize tainted wine. The last thing I want is for some family to drink a bottle of wine that is not right and then judge our wines by that experience."

Winery owners have stressed how frustrating it is for them to discover that even a small percentage of their wines are corked, ruined by TCA that shows up in the wine in the form of various off aromas. They also worry that some wines might contain sub-detection threshold levels of TCA, which can mask fruit aromas without being perceived as tainted, so it's difficult for the customer to discern whether the problem is with the cork or with the wine itself. But isn't the problem getting better? Haven't corks improved, making cork taint less likely?

Estimates on TCA contamination vary, depending on whom you ask. The cork industry claims that cork taint incidence numbers continue to decrease, and estimate that less than one percent of bottles are “corked”.  Critics, meanwhile, claim numbers of anywhere from five to ten percent. In more objective measures, data collected from the International Wine Challenge, where judges are trained to sniff out faults, shows that cork taint shows up in just under two percent of bottles (2006-2008 data).

“Premium factor”

Another point often raised in the Finger Lakes is the fact that the vast majority of consumers are not, in fact, laying bottles down to drink months or years down the line. Most wines are purchased for quick, almost immediate consumption. Why should a winery pay more for natural corks when a synthetic cork will do the job for at least a short while?

From our perspective, here's a strong reason to use the best possible closure: You won't effect change if you're signaling to the consumer that the wine should be drunk quickly, just as it always has. Finger Lakes wineries are producing some truly fine rieslings, and year after year, we find new evidence that the wines will age with grace and beauty. Some have even showed the capacity to improve over a decade or more. But consumers are not likely to begin laying bottles down if the message they receive is that it's not worth their while to do so. Change comes slowly, and with persistent consumer education. It's not always the cheapest short-term option that leads to long-term success.

This consumer perception of quality based on bottle closure is gleefully referred to by the cork industry as “premium factor.” To many consumers, there is just something special about popping a natural cork out of a bottle. One study of this phenomenon seems to confirm its existence, with consumers showing a strong positive association (e.g., they would pay more) for wines sealed with natural cork. Screwcaps show a strong negative correlation (perhaps a holdover from the Carlo Rossi jug wine days) and synthetics also show a mild negative correlation. Savvier consumers know, though, that screwcaps are not just for plonk, as many high-quality New World wines on screwcap demonstrate. But you don’t see entire countries (à la New Zealand) switching almost all of their production to synthetic closures.

In the minds of consumers, natural cork is simply the best possible closure for aging a wine. While the jury is still out on the scientific basis for such a belief, the court of public opinion has long been adjourned.

At a recent writers conference, Evan had the chance to see the new lineup from Nomacorc, a synthetic cork producer popular with New York wineries. The lower-end synthetics still look as fake as ever, and their oxygen transfer rates would be trouble for a consumer looking to lay bottles down. Their higher-end products look much more like natural corks than ever before. It's a clean, strong look. How do they perform? For the Nomacorc Select Series, their top-of-the-line product, the OTR is comparable to mid-range natural cork, providing, according to Nomacorc, a shelf life of between six and eight years.

At the conference, Evan tasted a series of wines that were several years old, closed under different grades of Nomacorc. On each occasion, he was able to correctly identify which wine was closed under better quality synthetic cork, and which was closed under lower-quality synthetic cork. But it wasn't easy. 

There are numerous factors that producers need to consider when choosing bottle closures for their wines.  Longevity, consumer perception, cost, risk of taint from the closure, and many more. There are also alternatives for wineries who wish to eliminate cork taint. Screwcaps are an option of course, but bottling under screwcap (1) requires a new bottling line (a capital cost many wineries simply can’t justify), and (2) comes with its own share of problems, which are beyond the scope of this piece. Some technical (agglomerated) corks (e.g., DIAM) undergo a special treatment process to remove TCA, but this process also adds to the cost. Then there are a host of other alternative man-made closures like the Zork, the VinoSeal, the Guala Seal, and many others, whose market acceptance and performance as closures are yet to be determined.

It's easy for us to prod Finger Lakes producers about natural corks when we're not paying the bills. And if we were producing Cayuga White or Niagara or many other varieties, we'd not spend extra cash on natural cork. That said, this is a region looking for more worldwide respect. This is a region that produces many wines that merit such respect. Most of the top producers close their rieslings with natural cork, but not all. It'd be a shame to see writers and consumers open a bottle and give up on the wine -- or the winery, or even the entire region -- before they pour a glass.

Heron Hill Moves to Screwcaps for Most Wines

By Evan Dawson, Managing Editor    

In a matter of weeks, Heron Hill Winery customers will find many of the winery's wines closed under screwcap. The winery recently completed the installation of a screwcap bottling line (pictured above) that owner John Ingle described as "not an insignificant investment."

Ingle described the plan for Heron Hill wines in simple terms: The wines that need to be preserved for as long as possible -- with no change or evolution that comes from gradual oxidation -- will be bottled under screwcap. The wines that Heron Hill considers to be capable of evolving into something greater will be bottled under natural cork.

"The cork does breathe, and the screwcap does not breathe," Ingle said. "So if you want the wine to evolve, it needs to breathe." He explained that the Ingle Vineyard designation bottlings will continue to see cork closures, as will the Heron Hill reds, such as Pinot Noir, Cabernet Franc, and Eclipse. The Heron Hill line of Rieslings will be bottled under screwcap.

"It looks beautiful," Ingle said about the first line of whites to be bottled under screwcap, the Game Bird White series. "I get a thrill every time I twist one of those things off. I feel like a part of the future has arrived."

It's worth pointing out that Ingle's approach differs from that of another prominent supporter of screwcap closures: Paumanok Vineyards' Kareem Massoud, who was recently profiled in NYCR by Science Editor Tom Mansell. Massoud sees screwcap as a safer closure, one that protects the fruit character of the wine. Ingle sees cork as an essential element in allowing a high-end wine to transform and evolve in the bottle.

Ingle explained that he was concerned about cork taint in Heron Hill wines, though he has not studied how frequently Heron Hill wines were showing discernible flaws from cork. "In my inimitable style of jumping out the window without looking, I decided it sounded like a great idea and we were going to do it," Ingle said. "I want Heron Hill to continue to be a trend setter."

Winemaker Bernard Cannac (pictured top and at right) has been a big supporter of the winery's shift. "We are using screwcaps only on wines that are more sensitive to oxygen, that is to say, wines that do not benefit much from bottle aging," Cannac said. "The Game Bird wines are very fruity and fresh. To preserve them in this stage with a screwcap is a very good option, because the wines will stay as fruity and refreshing as they were the day they were bottled, or close to it."

Cannac sees the proliferation of screwcap closures as a way to improve the quality of cork closures.

"Personally, I think that natural corks will always be used," he said. "The natural cork market was seeing too much demand, which might have tempered with their quality. With the competition of the screwcap, it will ease this pressure on the natural cork demand, which production is limited by the number of cork oak trees available. In turn, the quality of natural corks will hit higher and higher standards."

Regarding concerns about reduction or other quality issues with wines under screwcap, Ingle said research is on his side. "Wines are more predictable under screwcap," he said.

Truly Groundbreaking: Cornell Guides Growers In Search of the Right Land for the Right Grape

By Evan Dawson, Managing Editor

Photo at right shows the Data Layers map on NYVineyardSite.org; below is Professor Alan Lakso, courtesy Cornell

If you have ever thought, even for a brief moment, that owning a vineyard and winery would be fun, consider this: The first decision often turns out to be the biggest mistake.

That decision, of course, is what grapes to plant, and where. 

With support from the New York Wine & Grape Foundation, Cornell has launched an ambitious program and website dedicated to that pursuit. The site is NYVineyardSite.org. 

"We're seeing more people who want to get away from the corporate grind," professor Alan Lakso told me. "They sort of get caught up in the romance of starting a vineyard. Our goal is to help them make the best decisions before a few years have passed and they're looking around, asking what might have gone wrong. Because at that point we often have to say, 'There's not much you can do here. Plant somewhere else.'"

Lakso, along with his colleague Tim Martinson and other members of the Cornell staff, have to tell surprised winery owners the hard truth. Undoing a mistake can cost tens of thousands of dollars and many years. "You can waste a good site with the wrong variety, and you can waste good varieties on the wrong site," Lakso said.

The website's most valuable tool is the interactive map, which is easy to use even for those with no scientific background. It can be used to show color-coded temperature shading, showing which parts of a particular region are more likely to see temperatures fall below -5 degrees farenheit, or -10, or -15. It can also show the average growing degree days for given areas, or slope, or drainage.

It's cool stuff. If you're into that sort of thing, it's extremely cool stuff.

But it has a long way to go. 

"Our eventual goal is to allow users to click on a variety, like cabernet sauvignon," Lakso explained. "Then the map would show the conditions necessary to grow consistently good or ripe cabernet. The map would reveal where these conditions converged, indicating where a new cabernet vineyard would be likely to be successful."

Even in the Finger Lakes, I asked? 

"Sure, there are sites for it," Lakso said. "Far fewer sites for it than we'd find for riesling, but that doesn't mean cabernet can't succeed in the Finger Lakes. And the website will be designed to reveal those locations."

To get to that point, Cornell has a great deal more research to do. And they'll need to use more advanced technology to improve the map details. For now, the map is not nearly as specific as Lakso would like to see.

For example, Lakso explained that the so-called "Banana Belt" does exist. That refers to the southeast side of Seneca Lake, where growers like to say a combination of factors makes for slightly warmer sites. "To an extent, it's true," Lakso told me. "A major factor is wind, which can blow straight down the lake from the north in the winter, emptying out around Hector. If the wind shifts, as it can, that warm air is gone. But they tend to get that warm winter wind off the lake, which is protective."

So why, I wondered, doesn't the "Banana Belt" show up more visibly on the map?

"Right now, the map reflects a measurement of blocks of area, and they're rather large," Lakso said. "We're talking about three miles. Do you know how much can change in three miles? I've seen one single vineyard with six degrees difference from simply the top to the bottom. That's not uncommon. But the current map can't reflect that."

Cornell has 90 temperature sensors that can take updated readings every 30 minutes, but Lakso is hoping for more advanced aerial imaging, too. Improving the map will require more funding, and Foundation president Jim Trezise, who calls this one of his all-time favorite projects, is pushing hard for it.

"Alan’s project was by far the most costly," Trezise said regarding the decision to pursue it several years ago, "but also a great investment in terms of growing the industry and improving quality. The concept was to use modern, space-age technology to save current and prospective industry members a lot to time, effort and money." 

So is it working? Trezise said that it's hard to get a perfect gauge for how many growers have used the site, but he expects it's significant already. "They can do 90% of the necessary exploration on their computer with a cup of green tea on a Sunday morning," he said. 

Cornell takes no position on a single best or warmest site for grape growing. Decades ago, Hermann Wiemer communicated with such luminous figures as Dr. Nelson Shaulis. Records indicate that Cornell was pursuing the question of the warmest sites as early as the 1960s, and Hermann's communications indicated that a site on the west side of Seneca offered the most heat. That site is in Dresden, and a look at the new Cornell imaging map gives clues as to why. That warm winter air that Lakso described gliding down the lake runs into a nose of land that protrudes from the west side. That's Dresden. Then, looking west, there are no other bodies of water for many miles, so in the summer the warm air arrives in Dresden uninterrupted.

For this writer, it's a clue as to why the Dresden vineyards were able to withstand the infamous Christmas Massacre in the early 1980s, when so many other vinifera sites lost everything to a huge shift in temperature and extreme cold.

These days, Lakso wouldn't be interested in declaring one site or another as superior. Rather, he wants to find the sites that are superior for certain varieties of grapes. "We've already spoken to one grower who was going to plant pinot noir up their hillside, but looked at the website and realized that would be a bad idea!" Lakso said.

But without further funding, the website project could stall. "For 2011, there are more than $1 million in funding requests for very worthwhile projects, and less than $100,000 of private sector funds," Trezise explained. "The projects that don’t get funding won’t get done, a loss to the researchers and the industry. The researchers need to do something, so they might turn to other crops or, perish the thought, go to other universities."

Lakso has no plans to go anywhere else, but he'd like to see this project completed by the end of this year. The need, he explained, is greater than ever. And part of the reason is climate change, which one might assume would make it easier to grow grapes in places like the Finger Lakes.

"Not necessarily," Lakso said. "Summers have seen very little change over 30 years. But winters are getting milder. That's the biggest difference." 

So why wouldn't that automatically benefit growers?

"Climate change brings more erratic weather, and that's potentially a problem. Wild swings in temperature can be devastating, even if temperatures don't fall as far as they once did. If we get more of those warm stretches during the winter, some vines could begin to lose their winter hardiness."

The moment when things started to sound ominous, Lakso smiled. "Climate is what you expect, but weather is what you get. And we get something a little different every year. We're doing our best to understand it, and if you ask me, that's fun."

A Feather in Their Caps: Experimenting with closures at Paumanok

By Tom Mansell, Science Editor

In our annual wines of the year tasting, the NYCR staff tasted many, many delicious wines. One of the big winners of the day was Paumanok Vineyards, whose wines swept the three Long Island categories in which they were nominated -- Merlot, White Wine and Ice/Dessert Wine).

Interestingly, all three of the winning wines (and a fourth wine that was also nominated in the white category) were bottled under screwcap closures. All of the submitted wines showed interesting and in some cases unique aromas and flavors, often bordering on exotic and tropical.  

The Wines

The NYCR tasting note on Paumanok's 2009 Sauvignon Blanc read: 

The nose is extremely tropical -- typical of the sauvignon blanc musque clone -- with aromas of papaya, passion fruit, peach and mandarin orange with just a subtle grassy note beneath that fruit cocktail.

Similarly, when I tasted the 2009 Late Harvest Riesling during our wine of the year tasting, it showed a powerful tropical and stonefruit profile in addition to a spicy botrytis edge. It was so aromatically charged that a few of us (tasting blind) thought it could have been a muscat or gewürztraminer.

While I agree that clonal selection contributes to the tropical aromas, I would submit that the closure may also play a role.

Screwcap closures, specifically of the tin-lined variety, allow almost no oxygen to enter the wine after bottling. I don't want to get too much into the chemistry of sulfur in wine here (if you do, you can check out a piece I wrote not long ago for Palate Press). Briefly, there are many sulfur-containing compounds present in wine.  Some are pleasant, including 3-mercaptohexanol (passion fruit/grapefuit) and 3-mercaptohexyl acetate (guava).

These compounds make up a large part of the varietal character of sauvignon blanc. Reductive conditions in the bottle (i.e., the absence of oxygen ingress) can help maintain these sulfur-containing compounds in an aromatically-active state.

Another important sulfur-containing compound found in wine is dimethyl sulfide, or DMS. At low concentrations, DMS can intensify berry aromas. From the NYCR tasting note for the winning Paumanok 2007 Tuthills Lane Vineyard Merlot:

Intense aromas of blueberry, black cherry and black plum fruit are accented by vanilla bean, sassafrass spice, violets and speck.

Bold, but well balanced on the palate, there are gobs of dark fruit here -- blueberry, plum, cherry and even a little fig -- with layers of cola and spice and vanilla and violets and cured/smoked meat. The spiciness leans toward the exotic, with sassafras coriander seed and sumac.

While I don't exactly know what "speck" is, I do know that DMS increases with bottle age and in some cases has been shown to increase more rapidly in bottles sealed in screwcaps. Again, it's possible that the closure could have played a role in the wine's aroma profile.

Before this piece comes off as a rousing endorsement of screwcaps, I should mention that these closures are not without their problems.

A typical complaint about bottles sealed under screwcap closures is what is broadly called "reduction", but more accurately known as "sulfur-like off aromas." These aromas range from a rotten egg-like smell (hydrogen sulfide) to cabbage and rubber (mercaptans) and garlic (sulfides). An excess of sulfides like DMS, for example, can lead to a canned corn and/or low tide aroma in wines. 

This is not to imply that screwcaps "cause" reductive aromas. More precisely, the oxygen-poor environment that they create and maintain makes it easier to observe the sulfur-containing molecules that make their way into the bottle (for better or for worse... better for tropical aromas, worse for rotten eggs).  

Luckily, the aroma of hydrogen sulfide in bottled wine is easily taken care of via aeration or decanting. The mercaptans and sulfides, however, are more persistent, and won't simply "blow off."

I recently opened a bottle of Paumanok's 2008 Chenin Blanc during a chenin tasting and found a bit of reduction on it that did not go away over the course of the evening. The 2009 Chenin Blanc showed well at the WoTY tasting with a nice peach iced tea note, but there may have been a reductive note creeping in there as well. Surely, radically changing a wine's exposure to oxygen has a bit of a learning curve.

Paumanok Uncorked 

Paumanok started bottling wines under screwcaps three years ago. Today, all of their whites and rosés, most of their dessert wines, and even some of the reds can be found under screwcap. I talked with Paumanok winemaker Kareem Massoud (pictured right surgically removing a broken cork from a 1993 local red) Long Island  about the wines and the decision to use an alternative closure.

Massoud told me that part of the motivation for bottling aromatic whites and other wines with screwcap closures is simply avoiding cork as a closure. He cites Randall Grahm, saying that "any bottle of wine with a cork in it is corked." While this statement is likely to get you in trouble if you ever travel to Portugal, at the heart of the matter is the presence of haloanisoles like TCA (commonly referred to as "cork taint") in corks.  

Most serious wine drinkers can tell when a wine shows the musty, stale aroma of cork taint (estimates of proportions of "corked" wines can range from 2% to 5%).  However, Massoud seems more worried about when TCA's effects are more subtle. He astutely points out that even at levels below the detection threshold (which is remarkably low), TCA can suppress the perception of fruit. In other words, at low TCA levels, wine may not smell "corked", but rather display an absence of fruit... or just seem "off."

So in response to my question about the fruitiness of the wines in question, Massoud, one of the most technically savvy winemakers I have met in the industry, cites the lack of cork as a possible reason. He also stresses that meticulous viticultural practices (e.g., cluster thinning, leaf removal etc.) produce the best grapes and cleanest juice, leading to a ripe fruit profile.  

Basically, working hard to bring in the ripest fruit possible goes a long way.

The "sulfur off-aroma"-causing molecules generally arise from an abundance of hydrogen sulfide (generated by yeast) during fermentation.  "I'd be lying to you if I said I wasn't concerned about sulfides." says Massoud. He goes on to say that it's just good winemaking to manage sulfides during fermentation. The fewer sulfides that show up in the fermentation, the fewer will make it into the bottle. Active monitoring and management of fermentations in the cellar can mitigate the risk of these aromas.

Paumanok is also experimenting to observe the effects that screwcaps on the aging of their wines. Several bottlings (including Tuthills Lane Merlot) have been bottled under both screwcap and cork for comparison.  

The library of screwcapped wines is shallow to date, but continued observation will guide decisions about future bottlings on screwcaps. For example, it seems too early to say how some of the reds will age under screwcap vs. cork, or which varieties are more suitable for screwcaps over the long term.   

Interestingly, because of their radically different oxygen transmission rates, screwcapped wines are bottled with a smaller amount of sulfites than those sealed with cork. It will be intriguing to see how these wines compare in five to ten years or more.

The choice of closure is just one of a plethora of choices that growers and winemakers make from budbreak to bottling. As one of the most innovative wineries around, Paumanok is judiciously using alternative closures in an attempt to deliver the best wine that they can.  And in most cases, especially the Sauvignon Blanc and Late Harvest Riesling, it's working out exceedingly well.

Further Reading:

Segurel et al., Contribution of Dimethyl Sulfide to the Aroma of Syrah and Grenache Noir Wines and Estimation of Its Potential in Grapes of These Varieties, J. Ag. Food Chem., 2004

Brajkovich et al., Effect of Screwcap and Cork Closures on SO2 Levels and Aromas in a Sauvignon Blanc Wine, J. Ag. Food Chem., 2005

Brimstone in the Bottle: Sulfur Compounds in Wine

The Science of Biodynamics, Part 6: Organic Vinifera in the Finger Lakes

Irish Spring soap used to deter deer in Silver Thread Vineyard

By Tom Mansell, Science Editor

This series has provoked important conversations about biodynamics, organic growing, and sustainability. Organic grapegrowing should definitely be a part of this discussion, so just as I interviewed Alice Wise regarding organic viticulture in Long Island, the following is a profile of Richard Figiel and Silver Thread Vineyard in the Finger Lakes.

If you weren't looking for it specifically, you might not even know it was there. A small sign on Route 414, the Seneca Lake Wine Trail East, indicates that there is a Silver Thread Vineyard, but unlike many of the wineries on Seneca, it's not immediately off the main drag.

By the time you reach the bottom of a bumpy ride downhill on 3/4 mile of dirt road, you're convinced that you were in the wrong place -- except you see grapevines. Just before harvest began back in September, I journeyed out to Silver Thread to talk organic viticulture.

The winery itself is set into the hillside of a deep slope on the shore of Seneca Lake. I entered to find owner, winemaker, vineyard manager, and pretty-much-everything-else manager Richard Figiel in the cellar taking Brix measurements on gewürztraminer juice. The cellar was much cooler than the outside, even on one of few milder days of early September. Figiel immediately explained that the winery being practically underground provides natural temperature control for his fermentations, though the small wood stove (the winery's only heat source) is there for colder winter days. 

Silver Thread grows riesling, pinot noir, cabernet franc, chardonnay and gewürztraminer, producing 1,000-1,500 cases per year in what is essentially a one-man operation. Figiel has been growing grapes at this vineyard since the mid-1980s, and organic production was always part of his vision. Long before organic was a buzzword (when, according to him, the only people interested in organic were "hippies"), Figiel saw organic grapegrowing as "a responsible way to farm."

Organic in the Finger Lakes

The winery was certified organic in 1992, but a change in the buffer zone requirements (i.e., regulations for proximity to conventional vineyards) caused it to lose its certification in the late 1990s. Nowadays, it seems that NOP certification is not really the highest priority, though Figiel's commitment to responsible growing has not gone away with the certification paperwork.

Organic practices are still the baseline here, with only small deviations.

For example, not long after the period where the vineyard was completely organic, grape leafhoppers had become a problem. These insects feed on grape leaves and in high numbers can cause significant damage to vines. A treatment with a pyrethrum-based insecticide took care of the leafhopper infestation, and they haven't been back since.

The familiar, groomed herbicide strips of the average vineyard are completely absent from Silver Thread. In fact, parts of the vineyard are downright wild. Figiel uses no spot herbicides, and his main tool for weed control is the grape hoe.

Fighting fungus

One of the biggest challenges of organic viticulture is control of fungus, and the biggest problems in this region are powdery mildew, downy mildew and botrytis. Without the luxury of conventional fungicides, organic growers turn to interesting alternatives.

JMS Stylet Oil, which Figiel uses to control powdery mildew, is a highly refined mineral oil, a by-product of the petroleum industry. Its specific mode of fungicide action is not entirely understood, but a possible explanation is the creation of a physical barrier between fungal spores and the air, making it difficult for them to germinate. Other explanations include disruption of fungus membranes and the activation of natural plant defenses. Stylet oil can be effective against powdery mildew and botrytis, but is not effective against downy mildew.

Also part of Figiel's toolkit is Serenade, a fungicide whose active ingredient is a strain of Bacillus subtilis, a bacterium known to be agonistic to fungus. He also uses sulfur (of course) and copper hydroxide, though his soils have not shown a significant increase in copper over the years. "Ideally, in a year, I won't use it at all," Figiel says regarding copper. (See Part 3 of this series for information on copper fungicides and soil health.)

Finally, horsetail grows wild on the site, and Figiel makes his own horsetail tea to spray for fungus control.  Horsetail extract is rich in bio-available silica, which, as previously discussed in this series,  has been shown to have fungicidal properties.  It is also known as biodynamic preparation 508.

Regarding other biodynamic practices, Figiel composts pomace and local sheep and goat manure, and does add some biodynamic preparations to the compost, though biodynamics per se doesn't seem to be too important to him. You won't find horn silica or manure, and you won't find him consulting an astrological calendar for harvest days.

In the Winery

When it comes to winemaking, Figiel likes to keep it simple. No chemical yeast nutrients such as DAP are added. Most of his reds begin with wild fermentations, which are then finished off by inoculation with commercial yeasts. 

As mentioned, temperature control is accomplished by the cellar itself. Slight additions of SO2 (20-30 ppm based on pH) and fining with bentonite are common, as is sterile filtration at bottling, a regional standard.  Figiel characterizes his practices as "simple, rustic winemaking." I agree.

Silver Thread strives to be a winery that makes quality wines with as little impact on the environment as possible. This is evident in all aspects of the winery from the gravity-fed water supply, the meager wood stove heating, the natural temperature control of the cellar, and the commitment to organic viticulture. Figiel even dreams of replacing his tractor with horses to reduce carbon dioxide emissions. Horses would also provide a ready source of manure for fertilization and compost.

In 2010, Silver Thread's viticultural regimen was strictly organic. Some readers might be surprised to learn that there is an as-organic-as-possible vinifera vineyard in the Finger Lakes, but Figiel is not going to be the one shouting from the rooftops.

In fact, if you weren't looking for it specifically, you might not even know it was there.

 

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Further Reading:

Dell et al., "The Efficacy of JMS Stylet-Oil on Grape Powdery Mildew and Botrytis Bunch Rot and Effects on Fermentation", AJEV, 1998

Resource Guide for Organic Insect and Disease Management: Oils  http://www.nysaes.cornell.edu/pp/resourceguide/mfs/09oils.php

The Science of Biodynamics, Part 5: Field Spray Preparations: Stirring Controversy

By Tom Mansell

We now come to some of the most famous and well-known preparations in biodynamics, the field sprays. Cow manure or silica fermented in the ground in cow horns is practically the very symbol of biodynamics. These preparations are highly representative of the movement, but what, if anything, do they do?

Field spray preparations

Preparation	Main Component	Fermented in...	Proposed function (Steiner)	Proposed function (JPI)
500	Cow manure	Horn of a cow	"We preserve in the horn the forces it was accustomed to exert within the cow itself, namely the property of raying back whatever is life-giving and astral.... [T]he manure inside the horn is inwardly quickened with these forces, which thus gather up and attract from the surrounding earth all that is ethereal and life-giving."	Stimulates root growth and humus formation. Stir one hour.
501	Finely ground quartz or feldspar	Horn of a cow	"It will prove most beneficial with vegetables and the like.... [Y]ou will soon see how the dung from the cow-horn drives from below upward, while the other draws from above."	Stimulates and regulates leaf growth. Apply to foliage during the growing season. Stir one hour.
508	Horsetail (Equisetum) extract	N/A	Assume now that the moon influence is too strong....Thus we see the forming of mildew, blight, rust, and similar diseases....This [horsetail tea] we dilute, and sprinkle it as liquid manure... wherever we want to combat rust or similar plant-diseases.	For preventing or controlling fungus diseases.

These preparations are diluted in water, "dynamized" (more on that later), and sprayed onto vines.

Dynamization

What is dynamization? From Steiner:

"You must, however, thoroughly combine the entire content of the horn with the water. That is to say, you must set to work and stir. Stir quickly, at the very edge of the pail, so that a crater is formed reaching very nearly to the bottom of the pail, and the entire contents are rapidly rotating. Then quickly reverse the direction, so that it now seethes round in the opposite direction. "Do this for an hour and you will get a thorough penetration. Think, how little work it involves! The burden of work will really not be very great. Moreover, I can well imagine that [...] the otherwise idle members of a farming household will take pleasure in stirring the manure in this way. Get the sons and daughters of the house to do it and it will no doubt be wonderfully done.

Nowadays, some farmers have lots of spray to make and stirring by hand for an hour, in spite of Steiner's assertion, can be tedious. Thus we have seen the development of flowforms. Flowforms are large structures containing basins with geometries that allow water to swirl in oppposing vortices as Steiner suggests (seen at the beginning of the video below).

The theory behind this process is that it adds "energy" and oxygen to the water. What this "energy" is is ill-defined. From Nicolas Joly's book Wine from Sky to Earth: "Dynamization creates a profound intimacy between the solid and the subtle, between what one dynamizes and the water. The rhythm acts like an appeal." He then digresses into a discussion of artificial insemination of cows.

The addition of oxygen to the mixture, though, is real. Agitating the liquid will saturate it with oxygen, except this happens fairly quickly, not after an hour. The reason for this is that oxygen is not very soluble in water to begin with, only soluble at about 8 ppm, or 8 mg/L and it is even lower when the water is warmer. This low solubility is the reason we require the protein hemoglobin to transport oxygen in our blood, since the saturated level wouldn't be nearly enough to sustain our oxygen needs.

While it is possible that the fermented product could be consuming oxygen during this hour (fermenting wine, for example, would consume about 2 ppm of oxygen per minute), the small amounts of compost and/or silica added to the large amount of water make this unlikely.  Therefore, it is probably safe to conclude that dynamization of a preparation of 100L will add approximately 800 mg of oxygen, about half the oxygen contained in one breath of air.

Spraying Science

While preparations 500 (horn manure) and 501 (horn silica) have been found to contain high levels of cytokinins (plant stimulatory hormones), research done by Dr. Jennifer Reeve (as mentioned previously) showed that "The biodynamic field sprays (500, 501 and barrel compost) were not shown to have any effect on soil quality."  Thus, the mode of action, if any, of preparation 500 is likely similar to that of the compost preparations mentioned previously. 

For more information about compost preparations, see the previous post in this series.

Silica and Sunlight

Steiner's proposed mechanism for the effectiveness of preparation 501 is the intimate connection of silica to cosmic forces. Recent rationalizations of silica's effect on leaves include postulating that the silica crystals (ground quartz) focus and/or refract sunlight like a "prism", causing more sunlight to contribute to photosynthesis. 

The accompanying video has Mike Benziger of Benziger Vineyards giving his explanation of this phenomenon (around 1:18).

This is rather unlikely for several reasons. First, the silica is white and thus reflective, so some sunlight that could have fallen on the leaves is reflected back. Second, prisms do not magnify light or shift colors. When light is refracted through a prism, it is broken into its constituent wavelengths, not redshifted significantly. Third, even if the silica did "bend the sunlight more towards infrared", the maximum absorbance of chlorophyll occurs in the purple-blue range of visible light, with a minor peak in the red-orange area.

Essentially, the hypothesis that quartz crystals intensify the sunlight that reaches leaves is likely bunk.

Silica and Fungus

An interesting thing about silicon is that while it is mostly inert (in sand, glass, quartz, etc.), it can be converted into bioactive forms and used by organisms. One obvious example of this is diatoms, whose silica skeletons form diatomaceous earth (kieselguhr). Silicon is also taken up by plants and incorporated into stems or, in some cases, segregated to large silicous masses inside the plant. This is the case with horsetail (Equisetum), the dry weight of which can be up to 70% silica.

Indeed, spraying plants with bioactive forms of silica has been shown to help protect them against fungal disease. Most of this research has been done with rice, but there exists studies where spraying with potassium silicate decreased incidence of powdery mildew on grapevines. In a 1996 study in the American Journal of Enology and Viticulture, Reynolds et al. concluded that applying potassium silicate did reduce incidence of powdery mildew, but not as well as the fungicide Kumulus S (sulfur).

It's unlikely that silica is directly toxic to microbes, so what could the mechanism of this silica effect be? We might speculate that the spraying of silica onto plants via horsetail tea and/or preparation 501 might invoke some sort of resistance in the plant. The hypothesized mechanism is due to what is known as systemic acquired resistance. 

Essentially, since silicon naturally builds up at sites of plant injury and infection, it stimulates the production of the plant's natural defenses, antimicrobial compounds. Increased uptake of silica may trick the plant into thinking it is under attack, prompting the synthesis of these compounds so that when fungus does attack, the plant is at the ready.

It's possible, then that the silica, which enters a cow horn as inert quartz, could be converted by microorganisms into bioactive forms like silicates. In horsetail, much of the silica is already present in bioactive form.  If this is true, preparations 501 and 508 could indeed be providing some measure of fungus control in the vineyard, but it probably has nothing to do with crystals refracting sunlight or dynamization imbuing these mixtures with cosmic forces.

Further reading

R Steiner, Agriculture

N Joly, Wine from Sky to Earth: Growing and Appreciating Biodynamic Wine

AG Reynolds et al., "Use of potassium silicate for the control of powdery mildew [Uncinula necator (Schwein) Burrill] in Vitis vinifera L. cultivar bacchus", AJEV, 1996.

Fauteux et al., "Silicon and plant disease resistance against pathogenic fungi", FEMS Microbiology Letters, 2005

The Science of Biodynamics, Part 4: Hidden Alchemy in Compost

Yarrow flowers matured in a stag's bladder -- Preparation 502

By Tom Mansell

All images courtesy of The Millton Vineyard, Poverty Bay, NZ.

"For there is a hidden alchemy in the organic process." - Rudolf Steiner, Agriculture

At the heart of biodynamic farming are the famous preparations. In this post and the next post, we'll look at the contents of the preparations and their proposed effects and mechanisms or lack thereof.

This week's post will focus on the preparations added to biodynamic compost.

Compost Preparations

Preparation	Main Component	Fermented in...	Proposed function (Steiner)	Proposed function (Josephine Porter Institute website)
502	Yarrow blossoms	Bladder of a stag	"Its homeopathic sulfur content, combined in a truly model way with potash, not only works magnificently in the plant itself, but enables the yarrow to ray out its influences to a greater distance and through large masses."	Permits plants to attract trace elements in extremely dilute quantities for their best nutrition.
503	Chamomile blossoms	Cow intestines	"...has sulphur in the precise proportions which are necessary to assimilate the potash...assimilates calcium in addition.  Therewith, it assimilates that which can chiefly help to exclude from the plant those harmful effects of fructation, thus keeping the plant in healthy condition."	Stabilizes nitrogen (N) within the compost & increases soil life so as to stimulate plant growth.
504	Stinging nettle shoot	N/A	"A jack of all-trades... It carries within it the element which incorporates the Spiritual and assimilates it everywhere, namely, sulphur....Moreover, the stinging nettle carries potassium and calcium in its currents and radiations, and in addition it has a kind of iron radiation."	Stimulates soil health, providing plants with the individual nutrition components needed. "Enlivens" the earth (soil).
505	Oak bark	Skull of a domestic animal	"The calcium structure of the oak rind is absolutely ideal....[Calcium] restores order when the ether-body is working too strongly, that is, when the astral cannot gain access to the organic entity."	Provides healing forces (or qualities) to combat harmful plant diseases.
506	Dandelion flowers	Mesentery (gut lining) of a cow	"[i]t mediates the silicic acid finely, homeopathically distributed in the Cosmos, and that which is needed as silicic acid throughout the given district of the Earth.  Truly this dandelion is a kind of messenger from heaven."	Stimulates relation between Silica (Si) and Potassium (K) so that Silica can attract cosmic forces to the soil.
507	Valerian extract	N/A	"...stimulate [the compost] to behave in the right way in relation to what we call the 'phosphoric' substance."	Stimulates compost so that phosphorus components will be properly used by the soil.

The preparations (that's 503 at right) are usually placed directly into the compost pile in small amounts, typically 5-10 grams or less for the solid mass, though they can sometimes be sprayed in the field in addition.

In his fifth lecture on agriculture, Steiner argues that the nitrogen content of biodynamic compost is improved by transmutation of elements such as potassium and calcium into nitrogen by organic processes.

"I know quite well, those who have studied academic agriculture from the modern point of view will say: "You have still not told us how to improve the nitrogen-content of the manure."  On the contrary, I have been speaking of it all the time, namely, in speaking of yarrow, camomile [sic] and stinging nettle. For there is a hidden alchemy in the organic process. This hidden alchemy really transmutes the potash, for example, into nitrogen, provided only that the potash is working properly in the organic process. Nay more, it even transforms into nitrogen the limestone, the chalky nature, if it is working rightly."

This represents a misunderstanding of the nature of chemical elements, even by 1924 standards. The supposed phenomenon of biological transmutation, or the conversion of an element to a different element via a biological or organic process, quite simply violates the laws of physics.

It's important to note, though, that just because Steiner was a bit off in his explanation of the phenomena doesn't mean that these compost preparations have no effect at all. Many researchers have explored the effects of biodynamic agriculture, but until recently, these studies either compared conventional and biodynamic agriculture or lacked the statistical rigor required to make definitive conclusions. However, in the past decade or so, some intrepid researchers have taken a scientific approach to experimentation with the biodynamic preparations in an effort to gauge their efficacy and usefulness for modern farmers.

A review of peer-reviewed research into the effects of biodynamic preparations

One of the premier researchers in the compost field is Dr. Lynne Carpenter-Boggs, Biologically Intensive and Organic Agriculture (BIOAg) Specialist at the Washington State University Center for Sustaining Agriculture and Natural Resources (CSANR) and an affiliate Assistant Professor in the Department of Crop and Soil Sciences.  She has been an author on several peer-reviewed papers comparing the effects of agriculture using biodynamic preparations to organic agriculture.

Washington Com-post

A 2000 study published in Biological Agriculture and Horticulture showed some differences in compost quality between biodynamic and organic compost. The biodynamic compost had a consistently higher temperature and 65% more nitrate (likely due to aerobic nitrifying bacteria, not transmutation...) than the organic compost. In addition, phospholipid fatty acid analysis gave different results for biodynamic compost, suggesting that the microbial makeup differed slightly.

Also in 2000, the same authors published a study in the Soil Science Society of America Journal which sought to evaluate the differences in soil treated with organic or biodynamic compost. The authors also compared the results of composted soils to soils supplemented with mineral fertilizers. Over the many parameters measured, compost was shown to beneficial to soil quality, but no significant differences were found in any parameters between organic and biodynamic compost. 

From the conclusions section:

"The soil biological parameters tested indicated many differences between soils that had received compost additions and those that had not. Both biodynamic and nonbiodynamic composts increased soil microbial biomass, respiration, dehydrogenase activity [an indicator of microbial activity], MinC [an indicator of available carbon], earthworm population and biomass, and qCO2 [microbe respiration]. No differences were found between soils fertilized with biodynamic vs. nonbiodynamic compost."

Does it translate to plants?

Wheat

In 2010, Dr. Jennifer Reeve, Assistant Professor of Organic and Sustainable Agriculture at Utah State University and a former student of Dr. Carpenter-Boggs, was the lead author on a study of biodynamic compost and its effect on wheat seedlings. 

In this case, the compost contained grape pomace, which would be a readily available source of compost from wineries. The authors tracked compost parameters like the 2000 studies and found evidence of increased dehydrogenase activity, which indicated increased microbial activity in the biodynamic compost.

In addition, wheat seedlings were fertilized with the different composts. According to the paper, "In 2002, wheat growth with BD compost extract or BD compost extract plus fertilizer was always greater or the same as wheat growth with the control compost under the same conditions....Wheat growth in 2005 was similar between BD and untreated compost showing that possible differences as a result of BD treatment are not consistent year to year. Whether or not any small differences as a result of BD compost preparations would incur a practical benefit to the grower needs to be further investigated." Seedlings treated with either compost extract had higher shoot height and biomass and root biomass, confirming the beneficial effect of compost in general.

Okay, fine for wheat, but this isn't the New York Wheat Report.  What about grape vines?

One of the first peer-reviewed studies of biodynamic compost on grapes appeared in the prestigious American Journal of Enology and Viticulture in 2005. Dr. Reeve and Dr. Carpenter-Boggs were co-authors on this study. A three-year study of application of BD compost vs. organic compost (the only difference being the addition of preparations 502-507).

Biodynamically treated vines in this study also received field sprays (preparations 500 and 501). I'll go more into the effects of field sprays in next week's post.

According to the paper: "No consistent significant differences were found between the biodynamically treated and untreated plots for any of the physical, chemical, or biological parameters tested....Also, no differences were found in the more sensitive measures of microbial efficiency known as biological quotients: dehydrogenase activity per unit CO2 respiration, dehydrogenase activity per unit readily mineralizable carbon, and respiration per unit microbial biomass."

Analysis of the grape chemistry showed very little difference among the three harvests. One exception was 2003, slightly increased (though statistically significant) Brix levels (25.88 vs. 25.55) and approximately 2.5% and 5% increases in total phenolic compounds and anthocyanins, respectively. From the paper: "Based on the fruit composition data, there is little evidence the biodynamic preparations contribute to grape quality. The differences observed were small and of doubtful practical significance."

OK, so maybe there isn't any practical significance in grape chemistry. The wine is what's important!

The same wine grapes from the 2005 AJEV study were vinified and compared in a trained sensory panel. The first test was to see if the panel could tell any differences between wines made from organic and biodynamic grapes.

From the paper: "Triangle test results indicated no significant differences at p<0.05 [that is, 95% probability that the result is not by chance] between the 2001, 2002, 2003 and 2004 biodynamically and organically grown Merlot wines." 

Those that were able to correctly identify differences found slightly higher perception of in "musty/earthy" aromas in some of the organic wines. The only wine that was showed a notable preference was the 2003 vintage, where subjects preferred the organic wine over the biodynamic (p<0.1). 

This is the same vintage where biodynamic wines had slightly increased Brix, and phenolics, which may explain the result that in that the 2003 biodynamic wine was notably (again, p<0.1) higher in bitterness.

This is hardly a resounding endorsement for the quality of biodynamic wine over wine produced organically.

If there really is an effect, then how might it work?

The possibility of an altered microbial population in BD compost found in the 2000 and 2010 studies led the authors to consider microbial inoculation (i.e., the addition of beneficial microorganisms from the preparations) as a possible reason for the change in the compost. However, given the small inoculum (approximately 1 mg of preparations per kg of compost), this mechanism was considered to be unlikely but could not be ruled out. 

I asked Dr. Carpenter-Boggs if further studies have been done to examine the microbial makeup of the compost. Her response was that the small, subtle changes in biodynamic compost aren't really enough to justify further exploration of the microbial makeup, which would likely be painstaking and expensive.

According to Dr. Reeve, "any mechanistic hypotheses are pure speculation at this point." 

However, she seems to favor an explanation involving molecules that are capable of influencing plant and/or bacterial growth in small quantities. These hormones, molecules such as cytokinins, certainly exist in nature, but proving this hypothesis would be equipment and labor intensive, requiring extensive chemical analysis. 

Dr. Reeve admits "it's quite possible that these results are flukes,"  and she argues that there aren't enough practictioners of biodynamics out there to gain a statistically significant grasp on the benefits of biodynamics over organic farming.

Conclusions

Compost as fertilizer performs better in many soil health metrics (micronutrients, microbial populations, etc.) than conventional mineral/NPK fertilizer. However, the differences between biodynamic compost and compost managed without biodynamic preparations are few and relatively subtle. 

Compost with biodynamic preparations may have slightly altered microbial populations, but when BD compost is applied to crops, it gives little advantage over organic compost. Grapes produced using biodynamic viticulture treatments showed very little practical difference, and wine made from those grapes showed no statistically significant differences to a large panel of subjects.

Rigorous research into the effects of the biodynamic compost treatments may have produced small blips on the radar, but these results have either been inconsequential overall or irreproducible. 

Further research may elucidate possible mechanisms, if any. Meanwhile, one consistent result is the beneficial effect of compost on crops. So while composting may be beneficial, there's little evidence to support the use of biodynamic compost preparations.

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Further Reading

R Steiner, Agriculture, 1974 translation.

L Carpenter-Boggs et al., "Organic and biodynamic management: effects on soil biology." Soil Sci Am J., 2000

L Carpenter-Boggs et al., "Effects of biodynamic preparations on compost development." Biological Agriculture and Horticulture, 2000

JR Reeve et al., "Influence of biodynamic preparations on compost development and resultant compost extracts on wheat seedling growth", Bioresource Technology, 2010

JR Reeve et al., "Soil and Winegrape Quality in Biodynamically and Organically Managed Vineyards", AJEV, 2005

CF Ross et al., "Difference Testing of Merlot Produced from Biodynamically and Organically Grown Wine Grapes." Journal of Wine Research, 2009.

The Science of Biodynamics, Part 3: Organic Viticulture in Long Island

An earthworm heads back into the soil (source: schizoform on Flickr)

I think we can all agree that sustainability in viticulture is important. I mentioned in my first post that our discussion about the science of biodynamics cannot leave out organic viticulture. I asked Alice Wise, viticulturist at the Long Island Horticultural Research and Extension Center (LIHREC) about some of the nuts and bolts of organic viticulture in Long Island. 

NYCR: What are the primary challenges of organic viticulture in regions like Long Island?

AW: The goal is economically viable yields of high quality fruit – no matter what the management philosophy. Beyond that, growing season rainfall and morning dew favor fungal diseases such as black rot, phomopsis and downy mildew. The only National Organic Program (NOP)-allowed fungicide that provides significant control of downy mildew is copper, but no NOP-allowed material provides very good of control of black rot and phomopsis. Powdery mildew, on the other hand, is quite readily controlled by sulfur and mineral oil, both NOP-allowed.

NYCR: What are some ways to maintain nitrogen content in organic soil?

AW: Leguminous cover crops, though they must be tilled in for maximum benefit. There are organic nitrogen fertilizers such as peanut meal and others. They tend to be pretty expensive. For sandy soils, compost and/or composted manure helps with nutrition as well as nutrient retention. Realize that grapevines, at least vinifera on Long Island, do not need a lot of nitrogen so to me this is not one of the pivotal points of organic practice.

NYCR: How do organic treatments for downy, powdery, eutypa, botrytis, etc. differ from conventional treatments?

AW: The term organic is legally defined as it pertains to pesticide use. The NOP should have good information. Or go to http://www.epa.gov/pesticides/food/organics.htm. The effective materials allowed for use by the NOP are all used by non-organic growers to one degree or another, particularly sulfur and mineral oil.

The exception might be copper. Some growers won’t use copper, or limit its use, because it has a 2,600 day soil half-life and permanently builds up in the soil to toxic levels with continuous use. This has not been an issue here but is an issue in more established winegrowing regions.

NYCR: Are conventional herbicides/pesticides really that bad for the soil?

AW: Anything that is done to soil potentially alters the structure and the biology – herbicides, cultivation, cover crops, they all have impacts. Regarding the impact of herbicides, I have read/heard discussions with arguments on both sides. One measure of potential impact (or lack thereof) of herbicides on the soil is their soil half-life*. A relatively low half-life means soil microorganisms consume the material and transform it to CO₂ and H₂O pretty quickly. Many modern herbicides have low leaching potential and short half-lives and are not considered “bad” for the soil. My opinion is that there is no perfect method to manage vegetation under the trellis, each option has advantages and disadvantages.

*Note: A word about half-life: Most processes are best assumed to occur in a first-order way. That is, things will undergo exponential decay. The term "half-life" is a function of the time constant of this decay. More simply, half-life is the amount of time it will take for half of the material of interest to degrade. After two half-lives, 25% (1/4) of the original material will remain.  After 3, 12.5% (1/8), and so on. -tjm

NYCR: Copper is allowed in organic viticulture but – as you said – a common complaint is that it builds up in the soil. Are there any more eco-friendly copper alternatives at this time? Is copper buildup in soil as bad as some would claim?

AW: Copper use is limited and/or banned in some regions of Europe due to accumulation in the soil. Any soil copper level over 100 mg/kg is considered toxic and levels in French, Italian, Australian and New Zealand vineyard soils are not uncommonly found at 200, 300, 400+ mg/kg where copper has been used for decades. High soil levels of copper inhibit plant growth, impair soil microbial life, and drive out earthworms*. ‘Eco-friendly’ is not a legally defined term so I can’t comment on that. There are hydrocarbon-based, reduced risk options (for reduced risk definition, see http://www.epa.gov/pesticides/health/reducing.htm) for control of downy mildew but to my knowledge the only effective organic option is copper. Remember that both the active ingredient and inert ingredients must be approved by the NOP. Consequently, not all formulations of copper are organically approved. This holds true for other materials as well.

*Note: Earthworms are important to soils for many reasons, including their burrowing behavior, which increases soil drainage, and repeated turnover of the upper soil layer. Exposure to copper in earthworms at low levels can have detrimental effects on burrowing activity and at higher levels can be toxic to worms. Pictured right: Copper sulfate powder. -tjm

NYCR: You are running a trial on organic viticulture at LIHREC. Can you share any preliminary results?

AW: We are running the trial on chardonnay, probably the most difficult candidate for organic management. Overall, we have had difficulty with black rot, phomopsis and downy mildew in organic plots. Cluster rots have been problematic as well. 

However, we have harvested fruit every year, though yields have been reduced. Vine size has suffered as well and we’re not quite sure why. Our current thinking is that it is due to cumulative stress rather than any one factor. We ended up using a conventional nitrogen fertilizer this year just because vine size was declining so much. It definitely helped.

NYCR: I assume leaf removal is essential for disease control in an organic regimen. What are your thoughts on the Long Island cultural practice of 100% leaf removal from the fruiting zone vis-à-vis disease control and fruit development?

AW: The issue of timing and severity of leaf removal is not specifically related to organic viticulture. Leaf removal in the cluster zone is done for both quality and pest management reasons for VSP trained vines. The more extreme version of leaf removal is done, as I am told by vineyard managers who do it, so that only one pass has to be made rather than repeated passes to maintain adequate air flow and light penetration. Some feel ‘leaf stripping’ of the cluster zone has quality benefits as well and I have seen some data to that effect. I have also seen fruit with sunburn – we did a version of leaf stripping this spring and ended up with a lot of sunburn on exposed clusters on the west side of the trellis. Whether the fruit is riper, we’ll find out at harvest.

NYCR: How does the cost of organic farming compare to conventional methods?

AW: As organic vinifera is not common in the eastern U.S., a standard set of practices has not really been recognized. So much depends on which pesticides and fertilizers are used as costs vary considerably. Often organic management involves an increase in labor. However, there is just not any solid information on costs. The version of organic that we used in our trial was more expensive than conventional methods but we only evaluated spray materials. I would guess there might be data from the west coast where there are many organic vineyards. But it would not be completely relevant to Long Island as the viticulture is so different.

NYCR: Have you tested any of the biodynamic preparations (e.g., horn manure, horn silica, compost treated with yarrow, valerian, dandelion, etc.) in your vineyard? Why or why not? Did you discover anything?

AW: No, nor will you find any true replicated studies with these preparations. In science, we have to reduce potential variability in treatments as much as possible. To my knowledge, there are no legal standards for producing these materials, hence variability in product might account for treatment differences. Some may even fall into a legal gray area as well since any product applied for control of a pest must have EPA and NYSDEC approval. 

Regardless, since biodynamics involves a degree of faith or mysticism or whatever you want to call it, this does not lend itself to rigorous scientific evaluation. It may be interesting, but it would be hard to do a valid scientific study. And as biodynamics is a systematic approach, it might not make sense anyway to evaluate individual components. There was a west coast study that looked at conventional vs. organic vs. biodynamic over several years. It is summarized in the ASEV journal. I think it was done in WA and CA.

Note: One of the studies referred to can be found here and here. We'll be addressing the results of these studies in a later post.

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So it seems like downy mildew is a real bugbear. For those growers who want to avoid using copper, there is an alternative known as phosphites. Phosphites have been shown to be effective against downy mildew, but the fungus can develop resistance to this chemical.  

My understanding is that phosphite compounds are moving towards organic certification.

This brings up an interesting question. As was discussed in the comments section of part 1 of this series, sulfur, copper, hydrogen peroxide and mineral oil are "okay" to use in certified organic viticulture, but they are synthetic chemicals. Phosphite salts seem to be in the same vein.

What differentiates a fungicide like Captan from Phosphites?  Both are made in synthetic chemical processes.  Both have relatively short half-lives in soil.  Is it their overall toxicity?  Captan can be toxic to freshwater fish but Fosetyl-Al, a commercial phosphite preparation, can also be toxic to mussels. Both have been evaluated by the EPA and "can be used without causing unreasonable adverse effects in people or the environment."  

If "organic" includes synthetic products, then where do we draw the line on synthetic? Or should we?

---

Further Reading:

For more information about herbicides and pesticides, visit ExToxNet

Organic Agriculture Trials at LIHREC

H Eijsackers, et al., "The implications of copper fungicide usage in vineyards for earthworm activity and resulting sustainable soil quality", Ecotoxicology and Environmental Safety, 2005.

JR Reeve et al., "Soil and Winegrape Quality in Biodynamically and Organically Managed Vineyards" AJEV, 2005.

H Thao and T Yamakawa, "Phosphite (phosphorous acid): Fungicide, fertilizer or bio-stimulator?", Soil Science & Plant Nutrition, 2009.

For more info on downy mildew, see this post from Evan from about a year ago.

The Science of Biodynamics, Part 2: Moonstones OR Gravitas Vos Liberabit

The phases of a lunar eclipse, by tizianoj at Flickr

A key tenet of biodynamics is the influence of celestial bodies (e.g., the sun, moon, and planets) on agriculture.  While no one will deny the influence of the sun, it's not clear exactly what the moon might be doing to affect grapegrowing and winemaking.

Take the case of Aleš Kristančič of Movia in Slovenia. Thanks to glowing reviews and a high-profile section of Sergio Esposito's book Passon On the Vine, Movia has gained cult status for wine consumers. Kristančič is a very popular speaker around the world and is consulted often for his views on biodynamic winemaking. He makes a wine called "Lunar", farmed with biodynamic methods and bottled on the full moon. His explanation:

Flying stones. The "minerals" in the wine, which are somehow visible under a microscope, are lifted from the sediment by the gravitational force of the moon. It's not uncommon to hear biodynamic winemakers reference lunar cycles when deciding when to rack or bottle wine.

The Nature of Gravity

I think it might be prudent here to clear up some misconceptions about gravity. The force of gravity causes any two objects that have mass to accelerate towards each other. While its presence on Earth is obvious, gravity is actually the weakest of the fundamental forces, about 10^-37 times weaker than the electromagnetic force, for example. It also gets weaker with the square of the distance (i.e., objects twice as far away will exert four times less gravitational force on one another). The earth is so massive, though, that when it attracts your face to the pavement, it still hurts like heck.

As I mentioned, everything with mass has gravity.  The nearest massive object with enough mass to have non-negligible gravity is, of course, the Moon.  The Moon is approximately 1/80th the mass of Earth (which is still pretty massive), but it is also about 220,000 miles away from us. However, the effect of the Moon's gravity is still evident in the rising and falling of ocean tides.

Fit to be tide?

It's a common belief that human behavior is affected by the moon. Proponents of such a theory would argue that the moon's effect on tides is due to an affinity for water and that humans are about 60% water, so there must be an effect.  However, despite the repeated anecdotal assertions of emergency room personnel and police, incidences of trauma and traffic accidents, there is no convincing evidence that any such events correlate with lunar cycles.

Gravitationally speaking, there's really no difference between the new moon and the full moon. In both cases, the sun and moon are aligned, contributing the largest total gravitational pull (even though the Sun's is about 50% of the Moon's). For all intents and purposes, the gravitational effect of the moon on the Earth is identical on the new moon and on the full moon.

Tidal changes in the ocean are observed (1) because the ocean is enormous and (2) because solid material, while affected by the gravitational force in the same way, does not get pulled around in a significant way.  Indeed, the Earth's crust is affected by the Moon's gravitational pull, just not enough to be noticeable. 

Let's put some numbers behind this.  The acceleration due to the gravity of the moon (at the perigee, when the moon is closest to the earth) is approximately 1.34 x 10^-7 times g the Earth's gravitational acceleration. The force generated by the moon that opposes the Earth's gravity is one ten-millionth the force of the gravity of Earth. 

To put this into perspective, the gravitational acceleration in New York City vs. Los Angeles differs by about 0.06%, which is about 6,000 times more than the tidal difference in gravity.

Gravity affects every object with mass, not just water.  And it certainly doesn't discriminate between "minerals" and other sediment. Will your wine settle differently in LA than in NY? Yes, but the moon will have very little to do with it.

As for racking and bottling, while there may be a slightly different gravitational effect on a quarter moon (neap tide) than a full or new moon (spring tide), is it more likely that this infinitesimal effect will change the sedimentation profile of the wine, or that it will be affected by flow or shape of the tank or bumping of the lees with the racking wand or seismic disturbances or any other more terrestrial factors?

To rephrase an old adage, wines housed in a glass don't throw stones.

Further reading

M Sawicki, "Myths about Gravity and Tides," originally published in The Physics Teacher, 1999.

SO Lilienfeld and H Arkowitz, "Lunacy and the Full Moon", Scientific American, 2009

DA Thompson, SL Adams, "The full moon and ED patient volumes: Unearthing a myth", The American Journal of Emergency Medicine, 1996.

The Science of Biodynamics, Part 1: Ground Rules

Back when I was first getting into wine, I was shopping at Red Feet Wine Market, an Ithaca boutique wine shop. I noticed that some of their shelftalkers had little stickers (seen above) with the letters "O", "S"or "B".  Having lived in Ithaca for a bit, I soon gathered that "S" stood for "sustainable" and "O" stood for organic. 

I had no idea what "B" stood for.

"Biodynamic," owner Dewi Rainey informed me. "It's like organic plus." 

Intriguing.

She went on to explain that in addition to being 100% organic, grapes are farmed according to an astrological calendar and how racking and other winemaking processes were done according to phases of the moon. 

Okay...

Years later, this conversation has stuck with me. Phases of the moon? Astrological signs? Do people really believe this stuff?

It turns out that people do. Lots of them. Even the hallowed Domaine de la Romanée-Conti has vineyards given over to biodynamic farming. Many in the wine community are enamored by biodynamic wines. The notion of a vineyard in balance with nature appeals to people.

Since the first wines were made, the consumption of wine has been linked to some kind of spiritual experience (to Catholics, during the Mass, wine is transubstantiated into the Blood of Christ!). Therefore, it's easy to see why the spiritual language that describes wine is ubiquitious (e.g., "the soul of a great wine", etc.) and why wine grown using spiritual or cosmic forces may seem appealing.

Not everyone is crazy about biodynamics, though. 

Stuart Smith, winegrower and owner of Smith-Madrone Vineyards in the Napa Valley, recently started a blog called, flatly, "Biodynamics is a Hoax." In it, he provides critical readings of Steiner's lectures on Agriculture, in addition to pointed critiques of biodynamic farming practices in general. It's a highly recommended read if you are in to this sort of thing.

Organic Viticulture and Labeling

I'm not going to go into all the details on this, since there are plenty of resources out there on organic wines, but here is a brief synopsis of labeling standards for organic wine products. All claims of "organic" must be certified. The certifier in New York is NOFA-NY.

• 100% Organic:  All organic ingredients, no added sulfites
• Organic: at least 95% Organic ingredients, no added sulfites
• Made from Organically Grown Grapes: at least 70% organic ingredients, sulfites allowed
• Biodynamic:  Certified by Demeter USA or other biodynamic certification body (see below)

For those more visually inclined, I've included a handy Venn diagram (at right) of this process. Biodynamic doesn't really have any legal standing as far as the Tax and Trade Bureau (TTB) is concerned, but Demeter USA owns the trademark "Biodynamic" in the U.S., so certification is required for its use.

"Organic Plus"

So what's the difference between organic farming and biodynamic farming? Biodynamic farms go through a similar certification process to organic farms. According to website of Demeter USA, the major certifying body for biodynamic agriculture in this country:

"Biodynamic® farming is free of synthetic pesticides and fertilizers in the same manner as certified organic farming. In order to qualify for Demeter Biodynamic® status a farm must first meet the same 3-year transition requirement that NOP certified organic farming requires."

But there's more to it than simply satisfying organic standards. Biodynamic farming is a philosophy that treats a farm as one living organism. From the Demeter Biodynamic Trade Organization website (emphasis mine):

The Biodynamic method is distinguished from organic and sustainable farming methods by four key attributes:

1. A Paradigm Shift in Thinking: The Biodynamic farmer thinks in terms of forces and processes whereas organic and sustainable agriculture farmers think in terms of substances.
2. The Biodynamic Farmer Uses All Nine of the Biodynamic Preparations: The preparations are made following very specific methods. They are numbered, and are used in very small quantities to homeopathically treat compost, soil and plants. They include #500 Horn Manure; #501 Horn Silica; #502 Yarrow; #503 Chamomile; #504 Stinging Nettles; #505 Oak Bark: #506 Dandelion Flowers; #507 Valerian; and #508 Horsetail.
3. Understanding and Use of Earthly and Cosmic Rhythms/Cycles: The Biodynamic farmer is attuned to the daily, monthly and seasonal rhythms of nature, for example, the affects [sic] of the new and full moons on planting seeds and plant growth
4. Creation of a Whole Farm Organism: The Biodynamic farmer strives for this ideal, as described below. The farm depends on a minimum of input nutrients from outside the farm and, ideally, generates its own fertility through cover-cropping and the use of manure from animals that live on the farm.

So, for Demeter certification, there are are a lot of vague requirements (e.g., think in terms of forces) and some specific ones (use all the biodynamic preparations). The language here is important.

A Scientific Approach to Biodynamics

My intent in this new series of posts is not to dwell on the spiritual aspects involved, but to examine concrete observable phenomena related to biodynamic practices. Posts will include content on the influence of the moon on grapes and wine, the contents of the biodynamic preparations 500-508, homeopathy, and biodynamic grapegrowing and winemaking methods.  

I've read Steiner's lectures on Agriculture and Nicolas Joly's "Wine from Sky to Earth: Growing and Appreciating Biodynamic Wine" and so far I have found plenty of material to comment on. 

The series will also include profiles of some New York wine producers committed to moving their farms toward organic and/or biodynamic viticulture, which is not an easy task in any of New York's growing regions.

My initial impression is that some of the techniques espoused by biodynamics may actually produce results in the vineyard, but likely not for the reasons that Steiner and others profess.

Are there any specific practices that you'd like to see put under the scientific lens? I welcome your comments and suggestions below.

Pumped Up With Petrol: TDN and Riesling

By Tom Mansell, Science Editor

At TasteCamp, bloggers were generously treated to many library selections of riesling. 

Peter Bell guided us through two vertical tastings of Fox Run Vineyards rieslings (one pictured at right), of the dry and semi-dry persuasion. Bob Madill poured a library flight at Sheldrake Point Vineyard, and the Tierce brothers poured three years of Fox Run, Anthony Road, and Red Newt rieslings (and their collaborative effort, Tierce Riesling).  The oldest variations poured for the masses dated back to 2001.  

One character in particular that stands out in many aged rieslings from around the world is the so-called "petrol" note. This aroma can be somewhat polarizing. It's "goût de petrol" if you like it and it's "kerosene" if you don't. 

Many of the older Finger Lakes Rieslings we tasted along the way had a healthy dose of petrol, which is not surprising if you're at all familiar for riesling with a little age on it. What may seem surprising, though, is that a number of 2007 Rieslings we tried (and that I have tried in the past, even just after release) also had a bunch of petrol on them.

 The aroma compound we're talking about is known as 1,1,6-trimethyl-1,2-dihydronaphthalene, which is often thankfully shortened to TDN. 

Where's this aroma coming from, and why is it appearing in newer rieslings?

TDN itself is not often found in grape juice or in young wines. It originates from the gradual breakdown of protective plant molecules generally known as carotenoids.

Carotenoids are pigments that absorb light. They are important in leaves to support photosynthesis (and once the chlorophyll is gone from leaves in the fall, they give the leaves their oranges, yellows, and reds). In the berries themselves, these compounds absorb UV rays that would be harmful to the DNA and other cellular components.

Think of carotenoids as grape sunscreen. When UV light is high (i.e., in a year with lots of sunlight) carotenoids will build up during berry development to shield the cells from the harsh rays. Near the end of the growing season, the molecules break down into smaller components, some of which are precursors to very powerful aroma compounds, some of which are detectable in the parts-per-billion (micrograms/L) range.

These aroma compounds are often bound to sugar groups and known as glycosides when found in the must.  Glycosides are not aroma-active, so they won't be observable by smelling or tasting the must per se.  However, during fermentation, yeast enzymes liberate glycoside-bound aroma compounds, helping to create the complex bouquet that we love about wine.

So carotenoids can break down to form potent aroma compounds (1) during a hot harvest season or (2) by slow degradation of the compounds in the bottle over time. In a few years, a 2006 (from a cooler, wetter year) riesling may start to develop some TDN due to the bottle age, but some 2007s have already got some now due to the hot, sunny coditions. TDN formation can also correlate with water stress (and in some cases, atypical aging) but right now it's not clear whether the two are related or distinct phenomena. (aside: Yes, even in a relatively wet grapegrowing climate like the Finger Lakes, vines do occasionally suffer from water stress, which has led some growers to install drip irrigation systems.)

Not all carotenoid breakdown products are bad news, though. Beta-damascenone (cooked fruit, canned apple), Beta-ionone (raspberry, violet), and a fruity-smelling molecule known as riesling acetal are all carotenoid breakdown products, and are part of the essence of what makes wine "winey."

While it may seem like shading the grapes is a good way to reduce TDN (it is), there are many other reasons why it is desirable to have clusters exposed to sunlight and have an open canopy (see my post on leaf removal). A very recent paper in the Journal of Agricultural and Food Chemistry, authored by a team of viticulture researchers at Cornell, addressed this issue.

Current evidence indicates that leaf removal immediately pre-veraison (33 days post-berry set) leads to increased TDN in the juice and finished wine. According to the authors,"growers could implement leaf removal at berry set or postveraison for disease control, etc., without a resulting increase in TDN. Conversely, preveraison leaf removal could be employed if higher TDN concentrations were desired in wine."

So, exposure sunlight can increase TDN precursors and hasten their conversion to sugar-bound TDN in the grapes, which is then released by fermentation. Alternatively, carotenoids can break down in the bottle, leading to increased petrol with age. This could explain why years like 2007, which was hot and dry, and great for red wine production, may not be the best years for Riesling, compared to years like 2006 and 2008. 

I can't wait to see what the 2009 Rieslings have in store, but given the wackiness of that summer, I doubt there will be much petrol on them in their youth.

An eNose for Riesling? Machine trained to sniff out pleasant aromas

by Tom Mansell, Science Editor

What do humans like to smell?  One would think that smell preference would vary from person to person, given cultural and genetic differences. Some smells, though, seem to smell good to pretty much everyone, cross-culturally. In a paper released recently in PLOS Computational Biology, researchers working in Israel reported experiments with an "eNose," a chemical detection device that approximates the ability of the human nose to sense odor molecules. 

Human subjects were given aroma samples and asked to rate their "pleasantness".  The machine was then trained on this data, enabling it to detect the chemical aroma, then evaluate its pleasantness based on the human reaction. Once it was trained, the eNose was able to predict whether humans would find the scents of an array of essential oils pleasing or not.

The human participants in this study were from two different geographical areas, Israel and Ethiopia, and for the most part, the human preferences crossed these cultural boundaries. Smells that Israelis found pleasant were pleasant to Ethiopians, too.

So what does this have to do with wine?  Well, let's look at a recent highly-rated Finger Lakes Riesling tasting note from Lenn:

Exceptionally expressive on the nose, layers of lime, orange blossom, papaya, green tea and peach mingle, with the papaya and peach becoming more prominent as the wine warms.

The tension between energetic acidity and a slightly creamy mid-palate sets the stage for and frames layers of flavor -- papaya, kaffir lime leaf, juicy peach, orange blossom and golden raisin.

What were the top five essential oil aromas, listed in order of pleasantness?

1. Lime
2. Grapefruit
3. Bergamot
4. Orange
5. Peach

The full article is available here.

Wine 101: The Things I've Learned About Wine

By Tom Mansell, Science Editor

About a year ago, I started my own blog. About six months ago, I became the science editor for this publication. Several years ago, I was a scientist (I still am), but I knew next to nothing about wine culture. Luckily, I read a lot of magazines and websites so that I could learn all about things that didn't quite make sense to me from a scientific point of view.

Wine needs to breathe.

People say wine is a living thing, right? So living things have to breathe! Getting oxygen into wine actually softens the tannins, right there in the decanter! Never mind that the kinetics of tannin polymerization are on the order of weeks. Good thing I can buy a special "oxygenizing" glass to age my wine 10 years in 10 minutes! It must be some advanced technology.

Wine consumers only understand the 100-point system.

No one will buy a wine that gets 4 stars out of 5. That's like an 80 out of 100! A 5-star system should start at 2.5 stars, just like the 100 point system starts at 50. But really, you don't see any scores less than 70, so it should start at 3.5 stars.  See, this is all too confusing for the average consumer! Which brings me to my next point.

Wine tastes the same every time you drink it.

Humans all have the same number of taste buds, so everyone's palate is pretty much the same. Therefore, an 89 is an 89 to everyone, no matter how long after purchase you drink it.  After all, why have the precision of 100 points if an 89 could become a 90 or (gasp!) an 88 on a different day? Plus, aroma and flavor aren't affected by the food you consume with a wine, so tasting conditions really don't matter.  Bottle variation is a red herring.  What matters is that all the qualities of a wine can be reduced to a two-digit number. Simple!

Everyone hates hybrids.

The unholy mixing of Vitis spp. must be stopped! Disease resistance and cold-hardiness be damned. If it's not pure Vitis vinifera, it's crap!

Leaves are the enemy and must be destroyed.

My first article on this site was about the effects of sun exposure on grapes. I learned quickly that the only way to increase sun exposure to grape clusters is to remove every single leaf from the fruiting zone somewhere around bloom. Not only does this increase the cost of wine, but it gives otherwise bored vineyard workers something to do before harvest time. It's win-win.

Plus, it makes the vineyard look so pretty!

Winemakers and growers love it when people outside the industry tell them how to do their jobs.

How can you not love free advice?!?!

Growing Up Gewürztraminer: Varietal Character and Ripeness

Just-harvested Gewurztraminer at Keuka Springs Vineyard on Keuka Lake

By Tom Mansell, Science Editor
Photo courtesy of Keuka Spring Vineyards

I recently reviewed Sheldrake Point's 2008 Gewürztraminer for my own site, and as I looked over the technical notes, I noticed that winemaker Dave Breeden added acid to the wine. I was curious about that, given the fact that many wines inthe Finger Lakes are supported by their natural acidity. The concept of adding acid in a cool-climate region like this was a bit strange to me.

And, the alcohol content on this wine was listed at 13.6%, pretty high for whites in the region. Of course, I have seen Alsatian Gewürztraminers come in at 16% ABV. I wondered why the Gewürz that was going into these wines had such low acid and high alcohol (and, in turn, why it is harvested at such high Brix).

Defining ripeness

"Generally speaking, for Gewürz, acid and pH and really even Brix play no role for me in harvest decisions," says Breeden. For him, the most important parameter for ripeness in Gewürztraminer is the development of that classic lychee/rose varietal character. In the case of their 2008, the pH at harvest was 3.7 and Brix was 23.2, both somewhat high for the region and vintage for the average cultivar. The pH in the final bottling was 3.53.

The issue of pH came up again when I talked to Eric Fry, winemaker at the Lenz Winery, a producer of very good Long Island Gewürztraminer (reviewed here). 

"I'm a pH winemaker," he said in his characteristic blunt-yet-endearing tone. None of his wines go out the door with a pH above 3.59.  The primary reason for this is microbial stability. In the case of Gewürz, acid additions can contribute to balance as well, but the focus is on producing wines able to age, and pH plays an important role in that stability.

So why leave the grapes to hang so long? Fry says "If you want good varietal character, you have to wait for it."  Again, it seems like varietal character for Gewürz develops late in the game. If the flavor is right when the grapes are tasted, then it's time to harvest.

The harvest decisions of Breeden and Fry (i.e., waiting until varietal character develops in grapes by taste) are somewhat uniquely justifiable for Gewürztraminer. In many cases, varietal aromas in wine comes about when it is synthesized and/or released via fermentation (think about the difference between the aroma of must and the aroma of wine).  In the case of Muscat and Gewürztraminer, though, the aroma compounds that define the varietal character are present in the grapes themselves. Such aromas are known as primary aromas.  Another example is Concord, where the wine tastes like the grapes.

A rose is a rose...?

In 1999, researchers at Cornell determined that the signature aroma of lychee/rose in Gewürztraminer comes from a compound called cis-rose oxide (diagram at right). Unsurprisingly, this molecule is also found in rose petals. It is a product of reactions with monoterpenes (generally, floral aromas) like geraniol and citronellol.  The late development of rose/lychee might be attributed to terpene concentrations. Perhaps before cis-rose oxide can develop, the terpene precursors need to build up in the berry.

This hypothesis is supported in the literature. In a landmark paper, Wilson and colleagues noted that after véraison, levels of free and bound terpenes continue to build long after the fruit has reached maturity based on sugar and acid levels alone. After prolonged hang time, those levels began to decrease (likely due to degradation). This phase of terpene decrease could be the optimal ripening point for Gewürztraminer as well, since monoterpenes are the building blocks of cis-rose oxide.

Balancing the unique characteristics of Gewürztraminer

David Whiting of Red Newt Cellars produces two high-end single-vineyard Gewürztraminers (reviewed here and here). "Gewürz has a more complex balance than most white wines... [It] incorporates balances of sugar/acid/alcohol/phenolics. This four-way balance can be quite complex and sometimes counter-intuitive."

Many producers, including Whiting, apply some skin contact (the source of said phenolics) to add complexity and bitterness to the wines. Extended skin contact calls for increased microbial stability (again, pH plays a role). Whiting's grapes are also brought in at high Brix (23.5-25) and acid adjustments are often necessary.

As I mentioned on Monday, over the weekend I got the chance to taste Gewürz selected from around the world, and while I found the South African offering interesting, the clear winner for me was the Albert Mann 2007 from Alsace, which was well-balanced with pure Gewürz characteristics.  Albert Mann routinely clocks in at or above 13.5% ABV. 

Interestingly, Finger Lakes Distilling has recently released a Gewürztraminer grappa full of awesome Gewürz aromas. The grapes for the grappa were harvested around 23.5 Brix.

In regions like the Finger Lakes, Gewürz lives in the shadow of riesling, and it can often be polarizing. Development of its varietal character takes time, and many winemakers wait for it in spite of (or ignoring) Brix and acidity measurements.

Another important take-home message here is that while Brix and acidity are parameters that can help gauge the ripeness of fruit, individual cultivars can have idiosyncrasies that numbers alone can't account for.

As a final thought, my research into Gewürztraminer has caused me to wonder if there are regions where development of cis-rose oxide and Brix/TA coincide better. Can this be considered analogous to warmer regions where phenolic maturity lags behind sugar and acid numbers? Perhaps there is a climate, somewhere, where all the conditions are right for Gewürztraminer aromas and flavors to come into balance at the same time. 

For now, though, I'll enjoy the Gewürz that's being made in New York by winemakers who understand and are willing to tackle the unique challenges its ripening profile and winemaking presents.

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Further reading:

Ong and Acree, “Similarities in the Aroma Chemistry of Gewürztraminer Variety Wines and Lychee (Litchi chinesis Sonn.) Fruit“, J. Ag. Food Chem., 1999.

Wilson et al., "Changes in free and glycosidically bound monoterpenes in developing muscat grapes", J. Ag. Food. Chem., 1984.

Luan et al., "Metabolism of geraniol in grape berry mesocarp of Vitis vinifera L. cv. Scheurebe: demonstration of stereoselective reduction, E/Z-isomerization, oxidation and glycosylation", Phytochemistry, 2005.

No umlauts were harmed in the writing of this article.

Ice Wine Science, Part 2: Frozen Assets

By Tom Mansell, Science Editor

In my last article on ice wine, I talked about how volatile acidity is an important aroma characteristic in ice wine and how it can contribute to peach and pineapple aromas. To conclude our discussion, let's talk about some other famous ice wine descriptors, including honey.

For our purposes, it's best to think of ice wine grapes as late harvest (well, really late harvest).  Grapes are left to hang until December, January, and even February until they are frozen on the vine.  During this time, all kinds of physical, chemical, and biological changes are happening to the berries.

First, as the season draws to a close, the berries will continue to accumulate sugar (until photosynthesis stops) and lose malic acid to respiration. This loss of acid can have a huge effect on the finished wine, which may even require acid addition to balance the huge residual sugar. 

Cool-climate winemakers may find it absurd to have to add acid (and may feel slightly dirty doing so), but in this case the sweetness of the finished wine may demand it.

Second, noble rot (Botrytis cinerea) may start to move in, especially in tight-clustered varieties like riesling and vidal blanc. This mold penetrates the skin of the grape, drying out the berries and concentrating flavors, sugars, and acids. 

When berries are carefully selected, botrytis can be responsible for heavenly Sauternes and Trockenbeerenauslese-style wines.

Third, the skins of the berries can be physically damaged by birds, deer or simply freezing. Again, this can lead to berries drying out, but it can also lead to growth of other less-desirable organisms. The overall loss due to grape damage and deer breakfast partially justifies the higher-than-normal price of ice wine.

Aroma compounds

The combination of these three factors can lead to the formation of aroma compounds not usually found in dry wines.    Over-ripening has been found to lead to development of compounds normally found in older and/or oxidized wines.  While the aroma profile of ice wines has not been studied extensively, I think it's safe to speculate that the damage to berries in ice wine shares characteristics with botrytized berries, and many botrytized wine aroma compounds have been recently characterized. They include:

• Sotolon (spicy, curry, honey) (pictured at right)
• Furaneol (strawberry, cotton candy)
• Phenylacetaldehyde (honey, rose)

While biosynthesis of these compounds is not fully understood, it's likely that the first two are the products of sugar oxidation either in the berries themselves or by yeast during fermentation.   Phenylacetaldehyde is produced by the botrytis itself, and is also a key aroma component in honey.

Mouthfeel

As if smelling like honey weren't enough to provide the "honey" descriptor, ice wine's dense and rich mouthfeel make it feel like honey on the tongue.  This increased perceived viscosity is not due to glycerol formation (although glycerol in ice wine is  higher than in dry wines).  At the levels present in wine, glycerol does not contribute to increased perceived density or viscosity. 

The real culprit of increased density and viscosity is high residual sugar. This shouldn't be too surprising to anyone who knows that measurement of Brix, i.e., the concentration of sugars in a must, is based on density.

Overall, with its concentrated aroma profile featuring fruity and botrytized aromas (usually with a smidge of VA), and dense mouthfeel, ice wine is really something special.  It's something I'd like to see more of in the Finger Lakes. No doubt that it gets cold enough.  When conditions are right and harvest and fermentation are well controlled by vineyard management and winemaker, the results can be outstanding. 

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Further Reading:

Nurgel and Pickering, "Contribution of glycerol, ethanol and sugar to the perception of viscosity and density  elicited by model white wines." Journal of Texture Studies, 2005

Sarrazin et al., "Characterization of key-aroma compounds of botrytized wines, influence of grape botrytization." Food Chemistry, 2007.

To assist with this work, I tasted Sheldrake Point's 2007 Riesling Ice Wine and 2008 Cabernet Franc Ice Wine.  For my tasting notes, see my writeup on Ithacork.

Thanks to Sheldrake Point, especially Dave Breeden for helpful insights.

Ice Wine Science, Part 1: Volatile issues

By Tom Mansell, Science Editor

I recently had the opportunity to participate in part of the ice wine grape harvest at Sheldrake Point Vineyards, located on the west side of Cayuga Lake. Ice wine grapes can and should be harvested under specific conditions. Sheldrake Point winemaker David Breeden likes to harvest between 12 and 18 degrees Fahrenheit, but it's a delicate balance.

In frozen grapes, some of the water crystallizes into ice, segregating sugars and acids into a more concentrated solution. The degree of "frozen-ness" of the grapes will determine the concentration of the syrupy solution which will be extracted from the frozen grapes in the press.

If the grapes are too warm (closer to 18F), they may start to melt and juice extracted may not be concentrated enough. If the grapes are too cold, the juice may be too concentrated. Getting this right can be difficult and time-sensitive. In spite of careful weather-watching and scheduling, harvest times are basically up in the air until the morning thereof, when phone calls ring out into the breaking dawn and crews either wait a few hours or come in a few hours early. This particular picking was scheduled for Friday, then rescheduled for Saturday at 8 a.m., then moved up to 10 a.m., then back to 8:30 a.m.

Breeden tends to shoot for Brix levels between 35 and 40 (at right is Dave checking the brix of the must on Saturday). That's about 35-40 percent sugars by weight. 

At first, this might seem like a feast for yeast. Unfortunately, the concentrated sugary environment is not all that pleasant for them due to what's called osmotic stress. That is, the high dissolved solid content puts enormous pressure on the yeast cell membranes to maintain equilibrium.

Or to put it another way, it's like putting salt on a slug.

This stress leads to slow and difficult fermentations for ice wines. It also allows for some ambient microorganisms besides yeast to join the party.

Acetobacter and wine have been interacting for millenia; they're responsible for the conversion of wine into vinegar. In this case, while the yeast struggle to survive in their syrupy environment, Acetobacter and other spoilage bacteria can move in and set up shop on the surface, using ambient oxygen to turn ethanol into acetic acid (smell: vinegar), which can esterify into ethyl acetate (smell: nail polish). The combination of these two is known as volatile acidity (VA).

It turns out, though, that the biggest producers of VA in high-Brix musts are the yeast themselves. The stress caused by the high-sugar environment causes up-regulation of yeast enzymes that produce acetate. Thus, careful selection of yeast strain and tight control of fermentation conditions are important for making quality ice wine. 

At Sheldrake, Breeden manages osmotic stress in his fermentations by employing a method of gradual addition of the sweet must, which maintains a Brix level between 25 and 30 throughout the fermentation. The similarities of this method to a standard semi-batch reactor with substrate inhibition kinetics just sets the chemical engineering part of my heart all aflutter.

Too much volatile acidity can render a wine unpalatable, but like many faults, small amounts of VA can add complexity to a wine. Peach and pineapple aroma characteristics, for example (hexyl acetate, ethyl butanoate) can come from esterification of acetic and other volatile acids, and descriptors like this are very common in ice wine tasting notes.

The presence of some VA, due to osmotic stress on yeast in a high sugar environment, gives the bouquet of ice wine unique characteristics that set it apart from normal table wines. 

In the second part of our exploration of the science of ice wine, I'll discuss the palate and mouthfeel of ice wine and other characteristics that add to the honey-like richness that it provides.

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Further Reading:

Erasmus et al., "Impact of Yeast Strain on the Production of Acetic Acid, Glycerol, and the Sensory Attributes of Icewine", American Journal of Enology and Viticulture, 2004.

DEC Defends Hydrofracking, but Opponents Worry About Impacts on Finger Lakes Wine Industry

By Evan Dawson, Finger Lakes Editor with Tom Mansell, Science Editor

There is energy under our feet, and companies want to access it. The Marcellus Shale formation is about a mile deep, consisting of a rock-bound reservoir that runs through New York and Pennsylvania, among other states. According to experts, it's a natural gas basin that could provide 400 trillion gallons of natural gas.

For sake of comparison, that's nearly 20 times the current national output.

Crews can access the gas by drilling down -- and then horizontally, hundreds of feet below the surface. The shale contains tiny pores where the gas is trapped and practically inaccessible by conventional means.  A high-volume mixture of water, sand, and chemicals is pumped into the well, breaking up the rock and releasing the natural gas. The gas then is carried up the well line to the surface.

But it's the water mixture that makes people nervous. About 40 percent of that mixture returns to the surface and has to be treated. The rest remains below the surface, and opponents fear it will make its way up to the groundwater.

We've posted a graphic that illustrates the process (click it to enlarge). The graphic is from Al Granberg, courtesy of ProPublica under Creative Commons.

Finger Lakes Wine Industry Concerns
Opponents of hydrofracking in the Finger Lakes have two separate, very different concerns. The first centers on the surface wells, which some fear will create aesthetic pollution, harming tourism.

Sheldrake Point Vineyard Managing Partner Chuck Tauck recently sent a letter to his colleagues in the industry, warning of potential disaster. Tauck writes, "The impact on the tourism and the wine industry will be substantial, as our scenic rural and farm lands give way to industrial 200' drilling rigs,  five-acre well pads and hazardous waste holding ponds spaced as closely as one for every forty acres!"

The final plans for surface well locations have not been released, but supporters of hydrofracking argue the wells are a small price to pay for significant gains for the economy and energy.

The second concern focuses on the potential for polluted groundwater. Companies use a mixture of water, sand, a blend of chemicals to free natural gas from the shale deep below the surface. The chemicals added act mostly to regulate  the viscosity and consistency of the fluid. 

These companies argue that the blend is proprietary, and thus they should not have to make the details public. But if there is contamination -- to groundwater or to a worker involved in an accident -- opponents say there's no way to know how to best handle it. A recent draft of the Supplemental Generic Environmental Impact Statement (SGEIS) contains a proposal requiring all new permitted wells to disclose the composition of their fracking fluid.

For the wine industry, this is about more than drinking water. It's no secret that large amounts of water are needed to produce wine, and polluted groundwater could harm entire vineyards. Opponents envision a ruptured well infecting groundwater and wiping out entire vintages. Environmental regulators contend that while mistakes are impossible to eliminate entirely, the safety record thus far has been extremely sound, with very low percentages of disruptions.  The graphic below, adapted from Cornell Geology Professor Rick Allmendinger's website, shows the depth of the shale, its general economic potential, and the locations of wineries on the Finger Lakes.
 
"I understand the concerns - I do," an energy company executive, who asked not to be identified by name, told me. "But here's what happens: If one well has a problem, the media goes nuts with it. One family's well gets polluted water, and suddenly that becomes the only image that people attach to this process. And frankly that's not fair at all. We'd be out of business if this was a regular occurrence. It's in our best interest to do this as safely as possible, and when you compare this to just about anything else, it's extremely safe."

Opponents like Tauck contend that a relatively strong safety record could still include problems, and one is enough to do catastrophic damage. Tauck writes, "Unlike conventional drilling, drilling into the Marcellus Shale requires millions of gallons of water and chemicals, the disposal and regulation of which has been poorly addressed in the new document [the SGEIS], and has the potential to become a significant environmental disaster for the Finger Lakes, both with contamination of surface waters and contamination of aquifers and wells." 

At present, hydrofracking is exempt from Clean Water Act regulation since the fracturing occurs far below the level of groundwater.

The New York state DEC responds that regulators are comfortable that the hydrofracking process is safe and a very low risk to pollute groundwater. The fracturing happens hundreds of feet into the earth and the wells are created with thick liners. Energy companies point to a track record that includes a lower proportion of accidents than other energy exploration, including coal and oil.

Fewer Regulators to Handle Permits, Problems
New York state recently considered adding 30 workers to the DEC -- a move that would have helped handle the long list of permit requests. More importantly, say skeptics, it would have provided a broader capacity to monitor problems with hydrofracking. But the state's budget crisis forced lawmakers to scrap those plans.

Pennsylvania recently added 40 environmental inspectors to help monitor hydrofracking, a move that has added at least some peace of mind for residents. Other states also feature stricter permitting. But as with other concerns, New York's DEC downplays concerns about handling this issue. A recent DEC email addressed the heavy interest in Marcellus Shale energy: "There have not been and will be no shortcuts in permitting -- every well application will get all due scrutiny and oversight." 

Even so, a study by the Cornell University Law School found that the DEC is currently not equipped to handle all the new regulations and oversight that the current draft of the SGEIS calls for.

Even those struggling to make up their minds on this issue seem to agree that more information would be helpful. But the DEC has taken the position that the expansion of hydrofracking plans is not moving too quickly, noting that one out of ten wells in New York state are already being hydrofracked and there have been no adverse environmental impacts. Winemakers across the Finger Lakes want to know what's in the chemical mixtures, what the immediate steps are to handle an emergency, and how long the surface wells will be around.

Galileo famously said that wine is sunlight, held together by water. In reality it's largely water, and it's vital that the water remain clean, hydrofracking or not.

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Further reading:

DEC's Marcellus Shale Page

Cornell Geology Professor Rick Allmendinger's website

Cornell Law Study of the draft SGEIS

A Rare and Interesting Wine Fault: Ladybug Taint

One stinky bug: The Asian ladybeetle (Photo courtesy of USDA Agricultural Research Service)

By Tom Mansell, Science Editor

Have you ever picked up an ant and squished it between your fingers? In some cases, the ant has the last laugh, leaving your fingers with a sickly sweet, pungent odor sometimes described as "rotten coconuts." Ants secrete all kinds of different chemicals for communication, stress, antibacterial, antifungal and many other reasons.

Unfortunately, this is also true of insects in the vineyard. 

One particular insect can secrete a chemical so potent, as little as one bug per liter of juice can ruin an entire batch of wine. I'm talking about the multi-colored Asian ladybeetle, Harmonia axyridis. This little guy lives in lots of vineyards and farm fields across the country, eating aphids and doing some other beneficial pest control.

The problem is that when this beetle is under stress (e.g., being crushed in a bladder press), it releases some very potent aroma compounds, including 2-methoxy-3-isopropyl-pyrazine (IPMP, pictured right).

If you're really into wine, the word "methoxypyrazine" might look familiar. It's the name of a group of chemical compounds naturally found in grapes, particularly before véraison. Methoypyrazines are responsible for a variety of "green" or vegetal aromas in wines. IBMP (2-methoxy-3-isobutyl-pyrazine), the chief MP in unripe grapes, is responsible for a green bell pepper aroma, while IPMP smells like peas and rancid peanut butter.

Methoxypyrazines have a detection threshold in the neighborhood of 1-20 parts per trillion. This threshold is about thousands to millions of times more than many of the other wine impact odorants (with the exception of cork taint, which is similarly potent). To put this into perspective, 3-4 milligrams of IPMP would be enough to make an Olympic-sized swimming pool (~600,000 gallons) smell like peas.

While it's theoretically interesting to wine geeks like myself, finding so-called "ladybug taint" in a commercial wine is exceedingly rare, given that (1) ladybeetle infestations of the degree required to taint finished wine are somewhat rare and depend on the location of the vineyard, if there are soybeans nearby, and lots of other factors, and (2) the wine is usually revolting and unsellable.

Imagine my surprise, then, when I recently visited a winery and tasted a wine with unmistakable ladybug taint aroma. Needless to say, I immediately bought a bottle. The wine reeks of peanuts immediately after uncorking, and tastes even worse, with notes of mushy, school cafeteria peas.

I should note that this was not a New York winery, but the grapes were indeed from New York State. I don't necessarily want to mention the name of the winery because I can't prove that the IPMP is due to ladybeetles, but I can say with relative certainty that it is IPMP, and lots of it! If you want to try this wine for yourself, send me an email, though I don't believe it's for sale online. If you're around Ithaca, I still have a lot of the bottle left (for obvious reasons), so I'll gladly pour you some.

If you are trained to pick up faults in wine, sometimes you can become obsessed with them. It's important to remember that when it comes to wine, the absence of fault is not the presence of greatness. Indeed, some things that at very high concentrations can be considered faulty can be pleasurable and/or add complexity at low concentrations (Brett comes to mind, at least for some people...). Even methoxypyrazines can be desirable in some styles of wine (e.g., New Zealand Sauvignon Blanc). 

That being said, I may forget some of the really good, unfaulted wines that I have had, but I will never forget this one.

Further reading:

Review of methoxypyrazines in wine from Wines & Vines, featuring work from Cornell researchers on managing MPs in the vineyard

Pickering et al., "Influence of Harmonia axyridis on the Sensory Properties of White and Red Wine", American Journal of Enology and Viticulure, 2005

Fermentation Winespeak

By Tom Mansell, Science Editor

Have you ever smelled grape juice? Not Concord or Niagara juice but grape must that's about to become wine? It doesn't smell like much. It's kind of like fresh mown grass. How does this relatively un-aromatic juice evolve into complex, aromatic wine? 

Most everybody's grapes are in (except for the ice wine grapes) and it's now time for winemakers to figure out how best to turn their grapes into quality wine. Surprisingly, magic is not involved. 

Now in the spirit of Harvest Winespeak last month, In this edition of Winespeak, we'll explore some terms and techniques that winemakers use before and during fermentation, giving us an inside look at the winemaking process.

Barrel-fermented:  Somewhat self-explanatory, fermentation occurs in oak barrels. Not so obvious: Barrel-fermented wines will actually have less oak character than wines fermented in stainless steel and transferred to barrels for the same amount of time. The reducing environment of fermentation converts aromatic oak aldehydes into relatively neutral alcohols, diminishing their overall impact.

Cap management: Red wines are fermented on the skins, since the anthocyanin (color) and tannin compounds are almost exclusively located in the skins. Therefore, good contact with the skins is essential for extraction of color and tannin. The problem is that carbon dioxide produced during fermentation makes the skins float, creating a "cap" of skins and keeping most of the skin out of contact with the fermenting juice.  Winemakers have come up with many ways to ensure good skin contact, most of which involve submerging the cap, and some cap management techniques are listed below

Carbonic maceration: It's an appropriate day to talk about this, since today is the official launch of Beaujolais Nouveau worldwide. Essentially, 'carbonic' involves sealing uncrushed grapes in a tank with carbon dioxide. This leads to anaerobic metabolic processes within the grapes themselves (no yeast involved yet), creating all kinds of interesting chemical compounds including benzaldehyde (almond/cherry), isoamyl acetate (banana) and a little bit of alcohol.  During carbonic, the cell walls of the grapes break down, releasing anthocyanins (color) and amino acids. The latter helps to kickstart alcoholic fermentation by yeast, leading to wine that can be quickly produced and shipped out just in time for Thanksgiving. (further reading: Ronald S. Jackson, Wine Science, p. 529-534).

Chaptalization: Illegal in some places, done in many places. It’s a fancy way of saying “adding sugar” to a must before fermentation with the intention of increasing potential alcohol. Named after Jean-Antoine Chaptal, who discovered the relationship between sugar and alcohol in wine. Not to be confused with back-sweetening, which is adding sugar for sweetness.

Délestage: Often called "rack and return", this cap management technique involves draining a tank, then splashing the wine back onto the cap, breaking it up and redistributing the skins. This action also aerates the fermenting wine and can help blow off things like hydrogen sulfide (see YAN, below). Délestage can also involve the removal of seeds. 

Aside: It has traditionally been believed that seed tannins are much harsher and more astringent than skin tannins, so winemakers have encouraged skin contact over seed contact (using délestage, for example).  Anecdotally, this seems to make sense, since chewing on a skin is much nicer than chewing on a seed, even when the seed is crunchy and brown. However, new research from wine scientists concentrating on phenolic compounds seems to challenge this belief. They argue that the gallic acid found on seed tannins, which contributes to their harshness, is easily cleaved off during winemaking, making seed tannins less astringent than skin tannin (further reading: Tim Patterson, Wines and Vines, Oct. 2009). Tannin chemistry is very complex and more research is needed to make proper conclusions about the relative importance of seeds and skins in winemaking.

Esters: ESTER is not just a crossword clue, but a name for a series of chemical compounds, many of which are aromatic. In the case of wine, acetate and ethyl esters (descriptors of which include cherry, pineapple, pear, banana, etc., basically the whole fruit salad) are produced by yeast. It's thought that ester production is a reaction of yeast to toxic medium-chain fatty acids found in the grapes. Whatever the reason, if you smell fruit in your wine, there's a good chance you're smelling esters and you have the yeast to thank for that. Different strains of yeast can contribute different ester profiles (further reading: Soles et al., "Ester Concentration Differences in Wine Fermented by Various Species and Strains of Yeast", AJEV, 1982) and companies like Lallemand and ScottLabs use this as a selling point for different commercial strains. Fermentation temperature can also influence ester production and cooler fermentation temperatures can lead to fruitier wines, and whites are generally fermented a little cooler for this reason.

Extraction: As I said above, extraction of color and tannin is important in red wine. Anthocyanins are more water-soluble, so much of the color of a wine is extracted in the first few days of fermentation. Tannin extraction occurs in the mid-to-later stages of fermentation, aided by the alcohol created in fermentation.  Some extended macerations can last 30-90 days. Here it's really a winemaking judgment call.

Malolactic fermentation:  A secondary fermentation in which lactic acid bacteria convert malic acid to lactic acid, softening the acidity of a wine. They also produce diacetyl, a buttery-smelling aroma compound. For full details, see my recent piece in Palate Press.

Pectinase: An enzyme that helps break up the cell walls of grapes, aiding in extraction. It can be purchased commercially and added to must or to fermenting wine. Pectinase also helps settle out particulate matter in the must, aiding in clarification (further reading here).

Potential alcohol: Fermentation converts sugar to alcohol. I think we all know that one, but how many degrees Brix correspond to %ABV?  Generally, the rule of thumb is about 0.55, so a juice harvested at 20 Brix would produce 11% ABV. It's highly dependent on yeast strain and fermentation conditions. Final alcohol can be adjusted by chaptalization.

Pumpover: Another cap management technique. Juice is pumped from the bottom of the tank to the top of the tank, mixing everything around. Lacks the aeration and seed removal components of délestage. Pumping of any kind can crack seeds, releasing seed tannins into wine.

Punchdown: Probably the most romantic cap management technique (after pigeage by actually climbing in the tank). Usually, it involves standing over the tank and manually using some kind of tool to break up the cap.  (Being careful not to be overcome by CO2 vapors and falling in. It's a serious problem.) If you volunteer or work at a winery around this time of year, be prepared to do some manual labor in the form of punchdowns.

YAN (Yeast Available Nitrogen): A huge component of fermentation that's often overlooked. Yeast need nitrogen to create biomass, and that nitrogen is usually in the form of amino acids. If the nitrogen levels in the must are low, yeast start to get stressed out. They will break down their own amino acids, like cysteine and methionine, to make more. When this happens, they release the gas hydrogen sulfide (H2S). You have smelled this one before, it smells like rotten eggs. Smelling it during fermentation means the yeast are not happy. Sometimes it makes its way into the wine itself, leading to the need to aerate some wines in order to perceive more fruit aroma.

Fermentations can be supplemented with diammonium phosphate (DAP) to bring YAN up, but DAP is widely regarded as yeast "junk food", leading to yeast favoring biomass production over alcohol production, and possibly exacerbating the H2S problem (further reading: Bell and Henschke "Implications of nitrogen nutrition for grapes, fermentation and wine", Aus. J. Wine Grape Res., 2008).  Better control of YAN is done in the vineyard.  Many wineries do not measure YAN themselves (the test requires some expensive equipment and nasty chemicals).

Giving Hybrids Some TLC Could Lead to Better Breeding

Artists' rendering of the methyl anthranilate molecule, responsible for "foxy" aroma in grapes and wine

By Tom Mansell, Science Editor

Interspecific grape hybrids (hereafter: hybrids) were initially bred in the late 19th century in response to phylloxera, an American grape pest that migrated across the ocean to Europe and began to decimate the less-resistant vinifera vines, almost wiping out wine production. Since an American pest was the problem, breeding vinifera with American vines was a potential solution (rather the American way, eh? Screw something up halfway around the world, then try to fix it?), and the result was original French hybrids like Seyval blanc, Baco noir, etc. 

Once it became evident that the hallowed vinifera vines could be grown if grafted to American rootstocks (interestingly, also often hybrids), hybrid vines quickly fell out of favor in France, and (partially because of a shoddily-done study involving malnourished chickens) some eventually were subject to a European Union-wide ban.

Nowadays in France and much of Europe, it's highly discouraged and in some cases illegal to make wines using hybrid grapes. Many hybrids have parentage of Vitis labrusca, a native American grape, and wines produced from some can have a "Welch's grape juice" (aka "foxy" aroma), highly disagreeable to the sophisticated French palate, of course. That doesn't mean that it's not done, though, and there are simple ways of finding out if hybrid grapes have been added to a wine.  

Identifying hybrid characteristics

A key difference between vinifera and hybrids with American grape varieties is the way they synthesize their color compounds, called anthocyanins. In vinifera, the color compounds are usually found bound to a sugar molecule (glycosylated). This increases their stability and solubility in the wine. American varieties (and most hybrids therefrom) add two sugar molecules (diglycosylated). A simple test called TLC (thin layer chromatography) can be done on wine to determine if the anthocyanins have one or two sugars, and the presence of diglycosylated anthocyanin means the presence of hybrid juice.

A recent paper in the Journal of Food and Agricultural Chemistry has identified the genetic reason for the lack of double sugar addition in vinifera vines (a double mutation inactivates the protein responsible, called 5GT).  The authors also point out that the recently discovered gene responsible for the synthesis of methyl anthranilate (i.e., the principal "foxy" compound) is located very near the 5GT gene's location in the plant's DNA. The close proximity of these genes implies that they might go together during plant breeding.  Therefore, the relatively simple TLC test for the 5GT gene could possibly be an indicator of foxiness in the grape juice and could assist breeders in the future seeking to eliminate methyl anthranilate.

Impact

Today, one of the most important reasons to grow hybrids in New York state is their cold-hardiness. Hybrid vines can weather a cold winter far better than many of their vinifera counterparts. Disease resistance is also a factor, as hybrid vines can be bred for and selected by their resistance to diseases like powdery and downy mildew, as well as root pests like phylloxera and nematodes.

These are great reasons, but some consumers simply can't get over the foxy aroma that many hybrids bring to the glass. Consequently, the ability to easily breed cold-hardy, disease-resistant hybrids that lack foxiness could be advantageous.

The market acceptance of hybrids is another story altogether and certainly not my area of expertise (for the record, I happen to like many hybrid grapes). Regardless of where you stand personally, there's no denying the economic impact of hybrids on New York state wine and on cool-climate wine regions in general. 

Today, the science of genomics has opened doors to breeding possibilities beyond what Seibel and Baco could have imagined and there can be little doubt that hybrids will be at the forefront of the viticultural application of some of these technologies.

Harvest Winespeak Defined

 
A destemmer awaiting clusters (Photo courtesy of Ramón Mira de Orduña Heidinger)

By Tom Mansell, Science Editor

Anyone with any involvement in wine knows that the world of wine has a unique vocabulary. 

In a wine context, words like flabby, austere and even "mineral," take on meanings far from their dictionary definitions. Additionally, like in any trade, specific techniques for producing wine lead to specific names for such techniques. 

While many people in the trade read this blog, I'm willing to bet that the majority are interested wine drinkers. In this edition of what I hope will become a recurring series, I'll explore and define some words and phrases that you might see from winemakers and growers that are bringing in grapes for harvest and preparing for fermentation.

Brix: Many use "Brix" as a simple approximation for the percentage of fermentable sugars in the grape juice coming in from the vineyard. While this is pretty close, Brix is actually a measure of soluble solids in the liquid in grams solid per 100 grams of liquid at 25 degrees Celsius. Ninety to ninety-five percent of these soluble solids are in fact fermentable sugars like glucose and fructose. The remainder comprises non-fermentable sugars like xylose and arabinose, organic acids (malic and tartaric, mostly), and polyphenolic compounds.  Measurements of Brix can be done with refractometers (convenient in the field, by refractive index), hydrometers (by density, at right), or by infrared detection. Other measurements of the same property include the German Oeschle, the French Baumé, and the brewers' Balling and Plato.

Cold Soak: After red grapes are brought in, many winemakers will put them into cold maceration. The grapes soak for on the order of days, often with dry ice or liquid nitrogen.  Cold soak has been shown to increase anthocyanin (i.e., color) and tannin extraction in reds.  Other benefits include decreased oxidation due to enzymes like laccases, which can build up due to Botrytis infection.  Finally, the direct application of cryogens like dry ice can shatter the cell structure of some grapes, releasing helpful enzymes that can contribute to flavor development down the road (Zinnai, A.; Venturi, F.; Andrich, G., "Cold maceration in production of high quality wine," First international Symposium on Environment Identities and Mediterranean Area, 2006)

Crush: Pretty self-explanatory. Grapes are mechanically beaten up, breaking the skins and releasing juice.  Along with juice, crush releases esterases and pectinases from the berries that set about helping to clarify the must and ease the pressing process. During crush, it's important to consider the fate of seeds and stems, since breaking them could release bitter flavors and green aromas, again, depending on their ripeness.

Destem:  Pretty self explanatory as well. After harvest, clusters can be sent through a machine that removes the rachis (stem) of the cluster without damaging grapes. This is especially important for red wines, since fermentation occurs on skins. Sometimes, though, destemmers can leave jacks (individual stems) on the berries, so hand-destemming, while labor intensive, is not uncommon. Under some circumstances, stems can impart off-flavors to wines, including methoxypyrazines (green bell pepper, asparagus) and bitter ("green") tannins. Some winemakers, though, (notably locally, Tom Higgins of Heart and Hands Wine Company) claim that some stems in the fermentation can add complexity to the wine.

Free Run:  Juice (whites) or wine (reds) that flows out of the press before pressing has begun. It's generally looked upon as the best juice, since it's the most gently handled.  Free run will usually go into top-of-the-line labels and varietal wines.

Press Fraction: The complement to free run. Presses can reach pressures of up to 3 atmospheres near the end. To give you an idea of what that's like, it's the approximate equivalent of a weight of 200 pounds placed on the area of a soda can. Attempts to use high pressure to extract every last ounce of juice from the grapes, though, don't really pay off. The last (hardest) press fraction will often have higher pH (due to extraction of potassium ions from skins), higher phenolics (due to broken seeds, stems, etc.), and, generally, taste like crap. Interestingly, later press fractions turn out much clearer, since the buildup of skins and seeds (aka pomace) acts as a sort of filter.  Slightly less hard press (and much more drinkable) fractions will often end up in second labels or house blends.

Skin Contact: Essential for reds, controlled in rosés, usually minimal in whites, with notable exceptions. Anthocyanins and tannins, which bring color and structure to reds, are found in the skins, but bitter and undesirable phenolics can be found there as well, especially in not-so-ripe vintages. Again, judicious use of skin contact can be good for some white wines. Atwater Estate Vineyards on Seneca Lake uses a bit of skin contact (usually cold soak) to add some complexity to its Gewürztraminer, and Channing Daughters on the South Fork of Long Island ferments a few of its whites on the skins, leading to extremely interesting and unique wines like Envelope, Meditazione and the newly released Ramato.

Whole-cluster press:  Just what it sounds like. Whole clusters, stems and all, are placed into the press. Stems actually allow for better extraction of juice with lower pressure, which for whites leads to less extraction of bitter phenolics from the skins. Whole cluster press is a way to obtain absolutely minimal skin contact, so in a year where skins are not as ripe as usual, it's preferable.  Generally, its usage varies by year, grape, ripeness, etc.

This is just a snapshot of the many, many decisions available to the winemaker, and fermentation hasn't even started yet!

Leaf Pulling and Canopy Management: Let the Sun Shine In

Buried grapes in the research vineyards at Cornell Orchards, Ithaca, NY (left) and grapes more fully exposed to the sun at Peconic Bay Winery, Peconic, NY (right)

By Tom Mansell, Science Editor

As I checked my Twitter feed over the past few days, I noticed lots of tweets about the upcoming harvest from winemakers and growers. 

See the following from Lucas Vineyards winemaker Jeff Houck and Fox Run Vineyards owner Scott Osborn:

Apparently many places are doing some post-verasion leaf removal, as recently discussed on this site. It got me thinking about what's actually happening inside the grape when all of a sudden it's allowed to bask in the sunlight.

 

Vines, like wines, should be balanced

When we think about yield from a grapevine, we need to consider both fruit and vegetative growth (e.g., shoots, leaves, etc.). During the growing season, depending on rootstock, trellising, soil conditions, nitrogen availability, water availability and other variables, the balance between vegetative growth and fruit can tip towards vegetative, leading to a canopy that shades fruit, leading to less fruit development. This leads to more vegetative growth, and the cycle continues.

In particularly vigorous growing seasons, especially between veraison and harvest, temporary canopy management may be necessary to improve what's known as the microclimate of the grapes.

So why pull leaves?

Leaf removal has several purposes:

1. It allows more air to flow through the fruiting zone. This is particularly beneficial in humid climates (e.g., the Finger Lakes) because it keeps grapes drier, reducing susceptibility to fungi like Botrytis.
2. Sunlight warms the berries up. Increased temperature in the fruiting zone increases enzymatic activity inside the berry, leading to, as viticulture specialist Hans Walter-Peterson commented in this thread, increased degradation of acids. The increased temperature also tends to concentrate the berries, leading to a concentration of flavor and aroma precursors, as well as sugars.
3. UV light affects synthesis of certain compounds. Sunlight shining in on berry skins causes them to produce more flavonoids, natural sunscreen compounds that also happen to be important to color (anthocyanins) and flavor compounds (quercetin and catechins).

So leaf removal can improve desirable characteristics in the berries as well as help prevent rotten fruit, but it is a temporary solution and likely something that has to be done every year. Managing the canopy by other, more long-term techniques is a preferable solution.

For example, different vine-training systems can affect vine vigor throughout the growing season and allow for optimal sun exposure. On Long Island, for example, vertical shoot positioning (VSP) is often used to allow for maximum sunlight. As you can see in the picture on the right, come harvest season there is also quite a bit of leaf and shoot thinning that goes on.

Excessive sun exposure can lead to sunburn (literally) on grapes in some warmer climates. In fact, too much warmth actually can lead to degradation of anthocyanins, which can reduce color in grapes. Napa growers often worry about the amount of shade on their grapes. In cool climates like New York state, though, we generally want all the sun we can get.

Another point to consider is that increased grape exposure makes berries visually available and attractive to birds, who love grapes just as much as humans (so much so that they rarely wait for harvest and fermentation...), thus the bird netting in the picture on the right.  I'm told that turkeys LOVE gewürztraminer grapes.

At any rate, whatever winegrowers can do to keep those grapes disease-free and speed up the ripening process is OK by me. Let's hope the weather in September stays nice and dry... and brings us lots of sun.

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Further reading: Smart and Robinson, Sunlight into Wine, Winetitles, 1991

Pereira et al., "Microclimate influence on mineral and metabolic profiles of grape berries", J. Ag. Food. Chem., 2006 (abstract)

Matus et al., "Post-veraison sunlight exposure induces MYB-mediated transcriptional regulation of anthocyanin and flavonol synthesis in berry skins of Vitis vinifera", J. Experimental Botany, 2009(full text)