Could the high heat we've been having actually be good for our wine producing grapes? I asked Tarara Winery winemaker Jordan Harris about how the recent heat wave will affect the vineyards and ultimately, the wine. His reply:
Right now the vines are close to shut down just preserving energy for the health of the vine. If this weather maintains then we may have to do further fruit thinning (cutting extra clusters off) in order to achieve balanced ripening and maintain the health of the vine by keeping energy and photosythesis going to less fruit. In the end this normally means more intense and “bigger” wines.
The bigger reds that need a longer ripening period like Cabernet Sauvignon, Cabernet Franc, and somewhat Syrah and Merlot should be huge this year at this rate. Ideally for all the varieties as we get into mid August and through September and October the evenings at least will cool off to preserve acidity. This will help the fruit maintain integrity and get a longer hang period. It is really exciting to see that there is virtually no disease pressure this year which should help the fruit be clean and therefore get a longer hang time.
Overall, if the whether stays similar to how it has been you can expect massive reds with incredible concentration, lower acid and elevated alcohols as long as they are not watered down (we will not water down wines, but some do because they believe the lower alcohol offers a balance and because there is a different tax break at 14% alcohol). The whites will be more spotty, often times being flabby and high in alcohol while having so-so aromatics. There will be a lot of acid additions to whites this year, especially in heavy cropped vineyards. The best whites will be able to hang long enough to get concentration like you have never seen before in Virginia with exotic fruit characters, but that will only happen on lower yielded vineyards.
There are some varieties that suffer from the heat more then others. Our Pinot Gris and Viognier will have a harder time achieving the flavor development that is wanted before the sugar levels are too high and the acid is too low.
As with anything ion grape growing it just means altering some potential practices. In the grand scheme of things it will help to intensify the sugars and the flavor profile of the fruit. The only worries are that the sugars will ripen before the tannins and color are fully mature and that the grapes will have very low acid."