Deciding when to pick wine grapes is a very complex process. We evaluate both analytical ripeness and physiological ripeness when making pick decisions. Ideally the grapes would be physiologically ripe at the exact moment the sugars and acids are at the ideal levels. But most often you are balancing one thing with another. Sugars are high but tannins are too green... flavors are good but sugars are not quite where you'd want them... sugars are perfect but acidity has not dropped to an acceptable level... Michael Brill took a trip to Napa Valley to visit several Cabernet vineyards and he explains how we balance all these variables as we decide pick dates.
