QUESTION: I’ve heard that some wineries pick their grapes at night. Why?
ANSWER: It’s called the “fall” harvest season, but a good deal of winegrape picking takes place late in the summer, when it can still be very hot in wine country.
Typically, the just-picked grapes are placed in large bins, some of which can hold up to 2 tons of fruit. All that weight, combined with the heat of the sun, sometimes can cause the grapes to start fermenting even before they reach the wineries’ crush pads.
Harvesting at night helps prevent such “spontaneous fermentations” by taking the heat factor out of the equation.