White Wine Fermentation

Fermentation is the process where the yeast metabolize sugar and produce alcohol. The sugar content should be raised to between 20 and 22% (°Brix) if necessary. Brix levels are determined with a hydrometer or refractometer. Cane sugar from the grocery store can be used.

Warm the juice to 60°F before adding the yeast. The addition of a yeast nutrient to promote yeast growth is optional. Use commercially available dried yeast intended for wine production. Re-hydrate the yeast by suspending it in 10 times its weight of water
(1 gram water = 1 milliliter water) at 104°F. Stir lightly, wait 15 minutes, and then stir again. Add the warm yeast/water mixture to an equal volume of juice to be fermented over a period of 5 minutes to reduce the chances of a cold temperature shock to the yeast (atemperation step). It is important to have a temperature difference of less than 18°F between the yeast starter mixture and the bulk must you are adding it to. This atemperation step can be repeated when working with a cooler must (temperature closer to 50 than 60°F).

Allow the must (juice and yeast) to sit overnight at room temperature (68-76°F) before reducing the temperature to 55-60°F for the fermentation. A spare refrigerator will work well for this purpose. A special thermostat, available from home-brewing supply stores, may be necessary to control a refrigerator in the 55 to 60°F range. A cool temperature is necessary to control the fermentation and produce a fruity and delicate wine. Fermenting in a cool basement may give similar results.