Hens and Chicks
I was asked recently why the clusters in the vineyard seem smaller than normal, and why some berries seem especially small. Berry size varies somewhat every year, but in some years there is more variability than in others. Often it has to do with the conditions during bloom. There are also certain clones that are known to produce large and small grapes on the same cluster, but I don't know the physiological reasons for the size differential.
I can't answer whether there is a difference in maturation or flavor content, but I do think (without any experimental proof) that years in which we have the phenomenon (hens and chicks, peas and pumpkins) that the wine generally tends to be very good. I can say that smaller berries are usually better because they have a higher surface-to-volume ratio (higher skin-to-juice ratio). The "good stuff" is in the skins and because there is less juice and more skin to the smaller berries the wine ends up more concentrated and more complex. Big berries generally tend to make more dilute, simpler wines.
So, based on the appearance of the clusters right now I think we have the potential to make excellent wines this year. So far this reminds me of 1999, which also had small clusters with big and small berries. And that was also a year with a very cool (and wet) summer. In fact, by the end of September we were afraid we might not have a vintage at all. We harvested the Old Vineyard Block Pinot Noir on October 7 just to get something in, even though it wasn't really as ripe as we wanted. Then we had a beautiful October and brought in the rest a few weeks later. 1999 turned out to be a fabulous vintage; we can only hope the same thing about 2007!
As for the rain we're getting now - I think it's a good thing. We are pretty much past the point at which we need to worry about mildew and the grapes are not ripe enough yet to have to worry about botrytis. It's been such a dry year that we really need some moisture in the soil to carry the grapes through to full maturity.