In this cool growing season, we’re finally reaching the stage in the vine’s seasonal development called veraison. The most conspicuous sign of veraison is the change in color of the grapes from green to red (at least for red varieties), a process that takes several weeks. For white varieties, the change in color is less dramatic, going from green to a more golden color. Less conspicuous, but of greater importance, are other changes in the vine that take place at veraison.

At veraison, the vine, in essence, changes gears in several ways. It marks the end of leaf and cane growth, which should have already slowed down considerably earlier. Instead, the vine switches its resources to ripening the fruit. Prior to veraison, the grape development was concentrated on the formation of the seeds. From veraison on, the whole berry is the recipient of the vine’s resources. The process that begins at veraison involves increasing the sugar levels of the fruit, softening of the skin, seed color turning from green to yellow to brown, and other physiological changes.

Veraison’s end marks the time for the main fruit drop of the season. The best crops are those with the most consistency bunch to bunch. The end of veraison, however, leaves the vine with some bunches that have turned color, and some that have not. The ones that have not are laggards, and will unlikely fully ripen along with the rest of the crop. If allowed to stay on the vine, they will eventually turn color and get picked, but will still significantly lag behind the bunches that colored up on time. Left on the vine, these laggards would contribute unpleasant green attributes to the finished wine. So at the end of veraison, it is common to go through the vineyard and drop the bunches that haven’t fully colored up.

Irrigation practices can change after veraison as well. Prior to veraison, it’s important to get the vine to slow down its vegetal growth so that, come veraison, the vine doesn’t continue to direct its energies towards the pushing of ever longer canes with more and more leaves. The main means of doing this is controlled irrigation. By restricting the amount of water that goes to the vine, the vegetal growth slows, eventually stopping (hopefully) at veraison. Once this vegetal growth is under control, it’s less important to restrict the amount of water the vines receive. It’s often said that “stressed” vines produce the best wine. The stress is the result of the water restrictions that lead to the vine switching over from vegetal growth to fruit ripening. Once this water-restricted “stress” achieves its goal, water restriction is less important.

As you are no doubt aware, this year is one of the coolest on record, with the crop lagging several weeks behind normal. That means not only that veraison is occurring several weeks late, but that harvest is likely to be well behind schedule as well. One likely result of this is that the dropping of green fruit will likely be more than normal, in order to reduce the crop load–the vine can more quickly ripen a moderate crop than one that is too heavy. The thinking is not just to make sure the crop ripens, but that it ripens early enough to avoid the possibility of early fall rains that, by allowing the growth of mold, can adversely affect the quality of the fruit.

So, while every year veraison marks an important point in the development of the crop, this year it is being viewed with greater concern than in most years, as we try to balance the concerns of getting the crop ripe in time with the desire to maintain reasonable yields. And so many of the decisions made today can be judged right or wrong only once we know how the rest of the season plays out. As Mark Twain once said, climate is what you expect, and weather is what you get. The weather we end up getting will dictate how good a season we end up having.

I’m asking this question somewhat facetiously, as every vintage, from the industry’s perspective, seems like it’s the vintage of the century. But this vintage, at the least, is going to be different. As anyone living in California knows, this has been a very cool year both for people and grapes. Only time will tell for sure how the vintage will turn out, and there’s still lots of time for the weather to do a 180 and give us some real heat. But, at least so far, it’s looking like one of the coolest growing seasons ever.

So what does this portend for the quality of harvest? Looking at it from the point of view of the optimist, this could be one of the best vintages ever, particularly in the inland appellations. We know that the grapes are lagging several weeks, indicating that they will ripen under much cooler conditions than normal, if for no reason other than maturity is being pushed into a later, autumnal, season. I’ve written often about the benefits of ripening under moderate weather conditions, and how much of California is too warm to achieve this. This year will probably be the exception, particularly inland. What we’re seeing is a shift of normal weather patterns, where what would be normal for coastal (and cooler) regions is being experienced further inland. If so, this could be an exceptionally good vintage for the Central Valley.

Looking at it from the point of view of the pessimist, the worst case scenario is that the grapes aren’t ripe before the fall rains start. This puts the grape grower in a quandary: does he harvest, even though the grapes aren’t fully mature? Or does he wait, and risk botrytis and other infections that depend on rain? Either option is fraught with potential problems, and neither betokens a stellar harvest. Coastal regions, which in a normal year can still harvest under optimal conditions, are most at risk.

Assuming that the rains don’t come, there’s still an issue whether certain cooler, coastal, regions will be able to fully ripen their grapes. This seems like less of a concern to me than the possibility of rain, but for some coastal areas could be a concern, particularly if the cool weather persists.

Also, on the negative side, is the possibility that the cool weather will suddenly break, and we’ll get some real heat. Grapes, not acclimated to heat, don’t always respond well to a sudden warming. Some vines can shut down under these circumstances, particularly if they don’t get enough water. So dry-farmed vineyards could be particularly at risk. Even when the vine remains in good health, a sudden heat wave after cooler weather can result in shrivel, causing raisiny characteristics in the wines.

One question I have (and I’m not at all sure of the answer) is whether we can expect leaner, more classical, wines this vintage. It seems that this probably wouldn’t be the case in inland areas, where there should still be enough heat to fully ripen the grapes, but would be more likely the case in cooler regions.

One thing we know for sure—this isn’t going to be a normal, relatively stress free, California vintage.