The Winemaking Process

The process of turning grapes into wine is called vinification. Usually, the first step in the modern vinification process is the separation of the stems from the grapes. The next step is to crush the grapes to release the juice. If a white wine is being produced, the juice is separated from the skins at this point. If a red wine is being made, the juice is left with the skins to extract colors, tannins, and other substances.

After the grapes have been crushed into must, the vinification process continues with alcoholic fermentation. Yeast is added to the must, which consumes the sugars in the grape juice, and converts them to alcohol. Fermentation usually takes place in temperature controlled, stainless steel tanks. When the fermentation has converted the must to wine, the sediments are allowed to settle to the bottom of the tank. The wine is then pumped off to other containers for the next step in the process.

Most red wines, and some whites, undergo a second fermentation induced by bacteria rather than yeasts. This fermentation changes the malic acid into softer lactic acid, which lowers total acidity and makes wines seem rounder and fuller in flavor.

Many white wines and some reds to be sold young are settled and clarified in large containers for about six months. For more depth and complexity, some wines are aged in wooden casks or barrels. Wines are clarified naturally by racking. Sediments are allowed to settle to the bottom of the container, and the wine is periodically pumped into clean barrels.

At this point, wines are usually stabilized by refrigeration and filtering and are then bottled and stored for one to three months to balance their components. Wines aged in wooden barrels are often fined using egg whites or protein compounds and sometimes lightly filtered before bottling to remove any suspended particles.

Bottled wines are usually stored horizontally for up to a year before being sold to acquire harmony and to begin development of the tertiary aromas known as the bouquet. Some wines improve for a 10 years or more in the bottle, gaining a unique complexity in flavor and bouquet.