Take a drive out to Suisun Valley and admire the changing colors in the vineyards. If you look closely you will see - our green grapes are turning purple!
In the vineyard life cycle, this is called veraison, meaning the onset of ripening. It occurs every July and August and is a sure sign that the harvest season is near. The official definition of veraison is "change of color of the grape berries". Veraison represents the transition from berry growth to berry ripening, and many changes in berry development occur at veraison.
Veraison begins when green chlorophyll is broken down and the grape berries begin to accumulate their colorful pigments. The vine's leaves soak up the heat from the sun, turning it into sugars and carbohydrates that the vine can feast on. Some of the sugar is deposited into the grapes which will help them to taste more fruity and sweet. The more sunlight absorbed by the leaves of the vine, the sweeter its fruit becomes. Many of the sweeter wine varieties come from late-harvest grapes.
Fun fact: The grapes begin as hard, small berries, but by the time they're at full veraison, they will be much larger and pliable. Veraison occurs over a long period of time and each grape variety ripens at a different rate.
Harvest in Suisun Valley typically begins in August and will continue through the end of September.