August 17, 2015 | Neil Bernardi - Vice President, Winemaking
We have had a significant two day heat spell which is really going to kick harvest into gear. In addition, the presence of the two large and still unchecked fires in Lake County and more up in Trinity County have made it hazy, which lends a slightly post-Apocalyptic flavor to the beginning of harvest.
The effect of heat spikes on grape chemistry is one of concentration – the brix goes up dramatically, titratable acidity goes up slightly, and pH can stay the same or increase slightly.
Depending on what stage the vines are in the sugar can drop back down more in balance with the acid numbers with some cooler weather and irrigation.