Journal | September 24, 2016
Red Wine Fermentation
Yesterday was one of the easiest “big” days we’ve experienced. I’m always a bit apprehensive when day one involves large quantities, but all the equipment worked well. More importantly, the grapes were in excellent shape, so very little sorting was needed. They also de-stemmed well, probably a reflection of the ripeness level. Riper grapes release more easily from the cluster stem. Stems can contribute a green astringency to the wines. So now we have seven bins of crushed, de-stemmed grapes in bins. They were a bit too cool (low 50’s F), so last night we turned on the heat in the red fermentation room. Today we will inoculate with yeast.
Fermentation should kick off on Sunday then we will begin our twice daily pump-overs. The goal at this stage is to homogenize the fermentations and temperatures in each bin. We try to space the pump-overs every twelve hours, so there is an early morning crew (usually Shari and myself), and an evening crew (Jonathan and Dominick). After about three days the fermentations should be very vigorous and the skins will be pushed up to the surface to form a cap. At this time we typically switch from pump-overs to punch downs. The goal is to push the cap of skins back down into the fermenting wine for better extraction.
Every time we preform pump-overs or punchdowns we record the temperatures of each fermenting bin. For more fruit driven, earlier drinking wines we keep the temperatures in the 70’s F. For structured aging potential wines we are looking at the 80’s F. Alcoholic fermentation produces a lot of heat. Our 1.5 ton bins can quickly go from the 60’s to the 80’s in a matter of days. Temperatures are regulated by moving bins: outside at night to chill, in the cool tank room to maintain, in the red fermentation room to warm. However, its important to anticipate temperature spikes well in advance, as cooling 1.5 tons of actively fermenting, heat producing grapes doesn’t happen just overnight.