For weeks, the grapes have been ripening in a process known as "veraison," transforming from hard, opaque berries into soft, translucent fruit. Their color deepens, sugar levels rise, and they develop the flavor and aroma compounds that make wines unique.
But choosing the right time to harvest is no simple task. The winemaker can analyze the sugar content and acidity of the grapes, but because many of the flavors and aromas do not emerge until after fermentation, what lies in a grape is just the specter of the wine it will produce.
In the following video, Purdue viticulture specialist Bruce Bordelon and professor of enology and winemaker Christian Butzke explain the science—and guesswork—behind deciding when to harvest wine grapes.
Purdue viticulture specialist Bruce Bordelon and professor of enology Christian Butzke explain how choosing the right time to harvest wine grapes is both a science and an art.
Credits: Photos by Tom Campbell. Video by Kelsey Getzin. Web version by Andrew Banta. Through the Grapevine graphic by Russ Merzdorf.