By Evan Dawson, Managing Editor Photo: Owners Fred and Maressa Merwarth work the sorting line on the last pass of gewurztraminer Don't pick everything at the same time. It's a simple enough idea, and the reasoning is clear: By picking multiple times – or making multiple passes – Finger Lakes producers will have varying levels of sugar and acid to work with when they put together their wines. It's a model that is common in Europe, but less common in New York state. Many producers will make a decision: "Time to bring in the riesling." But at Hermann J. Wiemer…