Cameron Winery -- sustainably farmed, non-irrigated, Oregon pinot noir and chardonnay

Clos Electrique Veraison August 21 2012

But of course the French have a noun for the time at which the grapes start to turn from green to red.

Veraison in Clos Electrique Pinot noir

The grapes’ susceptibility to mildew begins to drop significantly at this point, which means that applications of chemicals meant to prevent mildew (such as sulfur and copper) can now cease.  Physiologically at véraison the very important plant hormones called “giberellins” begin to drop precipitously.

Why should the winemaker care at all about this phenomenon? Giberellins stimulate cell elongation, which is how the berries increase in size from tiny BBs to their current size.  When the giberellins drop, cell elongation ceases which means that berry size is now set.  Traditionally this is therefore the time to start dropping excess crop.

At this point the prize goes to the patient viticulturist:  as véraison  proceeds it soon becomes obvious which clusters are the furthest ahead in the ripening which allows one to selectively drop less ripe (green) clusters.   And perhaps in the end the most important aspect of veraison is that it is a metaphor for “light at the end of the tunnel”.  Harvest is now within sight for the optimist, while for the pessimist it is the light of an oncoming train bringing rain, rot and calamities!