Very simply stated, Wine is the natural product of
grapes. Fermentation is the process that turns natural
grape juice into wine through the inoculation or
addition of yeast to this juice, thus creating wine.
Yeast does not always have to be added to the grape
juice. Yeast will form naturally on the skins of the
grape clusters, and when mixed with the sugar in the
grape juice, a chemical process takes place that will
change the natural grape sugar into alcohol and carbon
dioxide. If the carbon dioxide is captured, you have a
sparkling wine. If the CO2 is allowed to dissipate, what
is left is WINE.
The process of making wine is actually quite simple to understand if you understand the basics. There are basic steps that the grapes will go through in general to produce wine, with variations depending on whether the wine is a still white wine, still red wine, or a sparkling wine.
First the basics. All wine production starts in the vineyard. The grape growing process is known as viticulture, or the growing of grapes. There are many variances in farming technique that can and will affect the outcome of the final product, but we will leave these for future reference on your part. Once the grapes have reached maturity and the brix, or sugar content of the grape is where the winemaker desires it to be, the grapes are harvested. Once harvested, the grapes are moved to a machine called a crusher or destemer. It is here that the grapes are separated from the stems, and gently pressed to extract the juices in order to start the winemaking process. The must, or juice is then transferred to a fermentation vat, where the fermentation either begins naturally from the yeast contained on the grape skins, or, the must is inoculated with a pure yeast strain. During the fermentation process the must is either separated from the skins and seeds through filtering (for white wine), or allowed to remain in contact with the skins for color and tannin extraction, (in the case of red wine). If the must does not contain enough sugar content for fermentation the juice is sometimes adjusted by the addition of sugar, (called chaptalization), this is an illegal process in California. The yeast is then adjusted to start the fermentation process and precautions are taken to insure that the temperature level is maintained where the winemaker desires it, and that the new wine is protected from air and bacteria. The new wine may either be fermented to dryness (allowing the yeast to consume nearly all the measurable sugar, or the process may be stopped before its’ completion in order to make a sweeter wine or a sparkling wine. Once fermentation is complete, the wine is racked off, or separated from the lees, (the fermentation residue) and then filtered for clarification. At this point the winemaker determines the type or style of wine he wishes to make, and the wine is either bottled for immediate consumption, or aged in oak barrels to enhance future potential, and then bottled for release or laid down for further bottle aging. And simply put, that is how wine is made.
If the wine that has been made is to be turned into a sparkling wine or champagne it has one more process to go through. This process is a second fermentation where the CO2 or carbon dioxide is captured in the fermentation container. If the second fermentation takes place in the bottle, then this is known as method champenois. Method Champenois is the only method allowed to produce true Champagne. The Champagne must be produced and bottled in the Champagne region of France, which lies apx. 90 miles north of Paris. If this “sparkling wine” is made anywhere else in the world it must be labeled a sparkling wine. In the U.S. the name champagne is often used as a generic term for sparkling wine.
