With temperatures over 100F for most of June and July, we expected the grapes to shut down. Thankfully, that has not occurred. Instead they are thriving and it appears that harvest for us will be a month earlier than last year. This means that we will begin as early as Thursday!
Having drought conditions this entire year, we have had the water on daily since February. The underground drip tape that we have between the rows is a very efficient way of watering - we lose no water to evaporation and it does not encourage weed growth as above ground irrigation would. The drought has not hurt us as it has other farmers. In fact, without rain there has been no need to spray for fungus or molds and no weeds means no hoeing! I prefer to get my upper body workout another way. :) Another concern with the storms here in west Texas is the threat of hail. Invariably the rain has hail with it which can devastate a vineyard as well as other crops.
How do we know harvest is near? First, the appearance of the grape, they change color. Then the amount of sugar in the grapes is tested. This is called the Brix. Brix is tested by taking a random sampling of grapes, crushing them to extract the juice and then either a hydrometer or a refractometer is used.
Wineries like a balance of sugar content and pH. We will be shooting for a Brix of 23 -24 on each of our varieties this year. Our Roussanne is at 22 and the Montepulciano is around 17. The Montepulciano was a test of only purple, ripe looking berries - so it was not precise but gives an idea. The Aglianico is a bit further behind the Montepulciano so we have not yet checked it.
Normally, as the Brix increase so does the pH which can present a problem for the wineries. Acidity is needed in wine for it to be stable. To balance the pH and obtain the proper acidity, the wineries add tartaric acid. There is, however, a legal limit to the amount of tartaric acid that may be added. If the acidity is too high and can not be controlled by tartaric acid, the wine is again unstable. This year however, the sugar content is gaining much faster than the pH, which is great!