It can be seen over at Gundlach Bundschu Winery in Sonoma, which for the past six harvests has used a machine that optically sorts grapes before they reach the crush pad. The machine can kick out up to 4 percent of the grapes that are hauled in from the vineyard, after they have already been put through a destemming machine. The grapes travel at high speed through the machine, where a computer takes a rapid-fire snapshot of the berries, and sorts them out through compressed air into a “good” bin and a “bad” bin.
The rejects are those that are raisin-like, small green berries, have poor color or are an awkward shape. The good ones are then crushed into a must that will be eventually turned into a reserve cabernet that can sell for as much as $125 a bottle.
http://www.pressdemocrat.com/business/6160754-181/north-coast-grape-growers-seeking?artslide=0