News from the vineyard 7/6/20

by Max Goldberg Liu

Veraison - the onset of ripening - is a turning point in the vine’s life cycle when it changes gears from producing energy through photosynthesis to storing that energy as sugar in grapes.

After flowering and fruit-setting, the grapes are hard, highly acidic, and green from the plant’s chlorophyll. Veraison replaces the chlorophyll with anthocyanins (giving red grapes their color) or carotenoids (in white grapes) and pumps sugars and other compounds from the vine into the berries. Over the course of ripening, the grapes swell with juice, their percentage of sugar (measured in brix) increases, and their acidity falls. Choosing to harvest when the sugar, acidity, and other phenolic compounds like tannins are perfectly balanced is one of the most important decisions a winemaker has to make each vintage.

In Burgundy, veraison classically happened in late July, although rules of thumb are obviously out the window in recent years with climate change. This vintage, winemakers are seeing veraison start to happen right now. The precocious vintage continues…