Wine Fermentation

Wine fermentation is the critical conversion of a grape’s sugar content into alcohol by extremely active little cells of yeast. The ancient process of fermentation takes simple grapes and chemically transforms them into the mosaic of complex aromas and flavors found in wine.

Where Does Wine Fermentation Happen?

After the grapes are picked in the vineyard, they are typically sorted into “good fruit” or “bad fruit” categories and the “good” fruit (free from shriveling, mold, etc.) is destemmed and crushed before the juice is fermented.

Wine fermentation typically takes place in stainless steel or concrete tanks as well as in neutral oak barrels.

Wine Fermentation and Yeast

The yeast used in fermentation may be naturally occurring, as those commonly found on a grape’s skin in the vineyard or they may be a specific strain of cultured yeast that the winemaker introduces to keep fermentation consistent, while producing desirable flavor and aromatic compounds.

Read More here…
http://wine.about.com/od/vineyardvocab/g/Wine-Fermentation.htm