By Lenn Thompson, Editor-in-Chief This is the last of the value whites I tried during a recent tasting, and guess what? Not only was it the unofficial winner, it's also the wine priced the lowest. Shinn Estate Vineyards 2009 Coalescence ($14) is a unique steel-fermented blend of chardonnay, sauvignon blanc, riesling and — get this — merlot blanc. The riesling that went into this wine comes from Seneca Lake in the Finger Lakes, by the way. The nose is citrusy but showed a bit more nuance than the other two values whites in the lineup, delivering minerally seawater character and…