The Color of Grapes

Posted 07/28/2008 at 03:48 AM by Dirk

The grapes are changing color in the vineyards. This is not some sort of light wave-length phenomenon. There aren't special lenses involved. There aren't any recreational aids. They really are changing color and it happens every year about this time. When they go from hard green berries to softening and turning red (if it is a red variety), it is called verasion. Since the French already had a fancy sounding word for it, we used the same term whether or not we speak French.

Verasion tends to be the time that a winemaker and a viticulturist can no longer afford to be in denial about the fact that crush is just around the corner. Actually, it always seems exciting. There are perfectly good scientific explanations for this important marker in the ripening process but, empirically, it's just cool. It is sort of a wine grower's cheap trick to gain admittance into the world of magic. (We just can't get it to switch back to the original color.)

The faster verasion happens, the better it is because it helps with the uniformity of ripeness. (See, there is a quality reason that we pay close attention to verasion.) Once a block starts verasion, it may take from five days up to 22 days but we always hope for less than 10. In truth, some clusters change color completely before other clusters even start. Even the individual berries get color at differing rates during verasion. Usually the shoulders of the clusters and the base of the cluster color up first but not always.

Verasion is our last chance to intelligently limit the crop in order to improve quality for the finished wine. Of course, one has to be able to predict vineyard yields to check if there is too much fruit or not enough. We want it "just right." (This year it seems that mother nature has set a smaller crop than normal.) To predict yields, Grant, our assistant viticulturist has to count clusters, weigh clusters, and measure clusters before applying math (remember that there are different row widths and numbers of vines per acre) and then add a little uncertainty factor of say, about 25%... (I would be one of the viticulturists who could get the yield prediction correct shortly after harvest.)

Back to verasion and thinning: We wait until the grapes have mostly turned red and then remove the clusters that are still green. Hence its name, "green thinning." There is only a one or two day window when it is at that ideal stage so the crews move quickly from block to block. Each block has its target instructions to best balance the needs of the vines with the year.

After a crew has made a green thinning pass, the number of clusters on the ground can be disheartening (OK, it looks as if we dropped ALL of the crop) but it can be as important a step as any other part of viticulture.

In a couple of weeks it will look as if all the vineyards are full of red clusters and visitors will think that they always "looked like that."

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