After fall harvest, California’s wine-grape growers hand over the reins to the state’s world-class vintners. Red, white, sparkling and dessert wines are made using different techniques that vary on fermentation time, aging length, aging vessels (oak barrels or stainless steel tanks), temperature and more. Each decision the vintner makes influences the character and flavor of the resulting wine.
Various fungi that kick-starts the fermentation process by converting sugar into alcohol.
When making white wines, the juice is separated from the grape skins immediately after the clusters have been crushed and destemmed, then it heads to fermentation. Skins can impart color and tannin that would overwhelm the white wine’s characteristically delicate flavors.
Yeasts are added to start the fermentation process, turning the juice’s sugar into alcohol. Vintners can then choose a number of paths to create the type of wine they desire. In fact, different winemaking practices can produce dramatically different wines from the same grape. For instance, wines can be fermented and aged in oak barrels, stainless steel tanks or a combination of both, all of which result in different flavors and characteristics. Fermentation, which is typically finished when the wine is “dry” (i.e. not sweet), can last anywhere from three days to three weeks.
In California, some varieties, particularly chardonnay, are allowed to sit on their lees (or spent yeast cells), which can give the wine a richer texture and often times greater complexity. Some vintners employ a secondary fermentation known as malolactic fermentation, which converts the wine’s malic acid to lactic acid, softening the wine and often giving an impression of “butteriness.” Aging white wines can last from one week to one year in stainless steel, oak or redwood containers, at which point the varietal is either bottled on its own or blended with other varietals and bottled.