VINIFICATION

he conversion of grapes to wine is called vinification and can be achieved in various ways. In general, the first step in the modern vinification process is the separation of the stems from the grapes, which are then crushed or, more often, rotated in cylinders under pressure which breaks their skins and releases the juice. There are three basic types of vinification: White wines The juice or free-run must extracted from the pulp is separated from the skins (whether light or dark) before fermentation begins so that they will give the wine little or no color. Rosé wines The juice is left on the skins of dark grapes briefly before or during the first part of the fermentation to extract a bit of color. Red wines The juice is left on the skins of dark grapes during the fermentation to extract colors, tannins and other substances - a process known as maceration. The liquid is sometimes separated from the pomace (skins, seed and pulp) before fermentation is complete. After the grapes have been crushed into must, the vinification continues with the following steps: Alcoholic Fermentation Grape musts consist of two main components, water and sugar, in solution with yeasts which multiply as they consume the sugars and convert them to alcohol while freeing carbon dioxide. This complex biochemical phenomenon is characterized by violent bubbling that creates considerable heat. Fermentation was often known as bollitura, or boiling, when it took place in open wooden vats in Italy. Today, it is often conducted in closed stainless-steel or cement tanks at controlled temperatures. Modern white wines are usually fermented cool to retain fresh flavors and the so-called primary aromas from the grapes. Drawing the wine off the lees When the alcoholic fermentation has converted the must to wine, it is allowed to settle so that the solid matter - known as the lees - collects at the bottom of the tank. Then the wine is pumped off the lees to other containers to begin the next step. Malolactic Fermentation Most red wines, as well as some whites, undergo a gentle secondary fermentation induced by bacteria rather than yeasts. This malolactic fermentation transforms sharp-flavored malic acid into softer lactic acid, a process that lowers total acidity and makes wines seem rounder and fuller in flavor. Stabilizing and aging Each type of quality wine requires special treatments to stabilize and mature it before it goes into the bottle. Many white wines and some reds to be sold young are settled and clarified in large containers of cement or fiberglass or, prevalently, in stainless-steel tanks. The process usually takes about six months. For wines of depth and complexity, whether red or white, the best containers for aging are usually wooden casks or barrels. Italian winemakers increasingly prefer oak barrels of limited size. Wines are clarified naturally by racking, periodic pumping into clean barrels, which leaves behind the solid particles that settle to the bottom. The aging process stabilizes and harmonizes wines which extract from oak noble tannins that enhance flavor. The wood's permeability permits minuscule amounts of oxygen to enter the wine, favoring development of secondary aromas which are more refined and elaborate than primary aromas. Wood aging may last from four months to a year for white wines in small barrels and up to three years, sometimes more, for reserve wines in casks. Fining in bottle Young wines are usually stabilized by refrigeration and filtering and are then bottled and stored for one to three months to balance their components before they go on sale. Wood-aged wines 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 six months to a year before being sold to acquire harmony and to begin development of the tertiary aromas known as the bouquet. Some wines can improve for a decade or more in bottle, gaining unique depth and complexity in flavor and bouquet.