FermentationAt Spring Mountain they shoot for a peak fermentation temperature rising to 85°F after the cold soak. Fermentation after the cold soak lasts from 3 to 45 days depending upon vineyard, block, grape maturity, and grape variety. Decision making here is by taste and experience. Early maturing, heavily colored, high tannin grapes from high stress blocks may develop full balanced flavors in relatively short fermentations, while later maturing grapes of exceptional quality may benefit from extended maceration. All tanks are tasted daily. Decisions are made based on sensory evaluation, not recipe; though experience gained from year to year does guide what they look for and expect.
Fermenting tanks are pumped over twice a day. In a year where grape flavors are unusually intense they will pump over only once. One-half to one-third of the volume of the tank is sprayed over the cap on the fermenting must during each pump over. The pump- over is gentle and the fermenting liquid is distributed evenly through a revolving sprinkler. They pump over through a screen to a sump which also aerates the must. This keeps the yeast strong, lowers alcoholic conversion, and possibly helps in the development and polymerization of tannins. As the fermenting must drops in sugar, the length of time of a pump over is shortened. Once dry the lot may be given extended maceration on the skins. If this occurs they discontinue pumping over.
Primary fermentation occurs in jacketed stainless steel containers of 5, 6, and 10 ton capacities. The red grapes are conveyed directly to the fermenting tanks from the crusher. Batch sizes vary from two ton lots to full fermenters. Occasionally they have a very small lot that needs to be kept separate. They use ½ ton plastic bins with open tops and lids for the primary fermentation of these tiny lots.
Free run and press wines are kept a temperatures between 68°F and 72°F until the completion of malolactic fermentation. At the completion of malolactic fermentation the wines are racked with a vigorous splash, and then receive a small addition of sulfur dioxide.