Flowering and Fruit Set
If there is rain or heavy fog during the time that the grape clusters are flowering, the grape cluster will be less full. If you have ever had an ear of sweet corn where there were kernels that were stunted, you get the general idea. When the clusters come in with many undeveloped grapes, we call that situation “shatter.” It will look like there are grapes missing from the cluster. To add insult to injury, the undeveloped grapes cling to the bunch as small, green, bitter bb’s called shot berries. Not only robbing the vineyard of grape volume, but also adding an undesirable element to be dealt with at harvest.
Growers deal with fruit set by planting the right varietal in the right place. If the vineyard is near the coast where there is more fog, varietals with a long flowering process like Merlot can suffer a lot of shatter. This is a problem for some of the Merlot planted on Spring Mountain. Both Pride Vineyards and Paloma Vineyards on Spring Mountain make exceptional Merlot wines. Their total cases of wine can vary widely from year to year due to Shatter. That is the blessing and the curse of mountain Merlot. The difficult soils and slope provide concentration that makes these wines special. However, the same mountain means they are more susceptible to Shatter caused by the coastal fog coming over the top of the mountain. Mother Nature gives and she takes away.
