Oenologie is a facinating and complex field that offers those who make the effort to understand it a wonderful source of discovery and pleasure. The underlying principles for making white, rosé and red wine are essentially the same, although the process for making each differs.
Wine is a living product that evolves with age, defined as a “natural fermented beverage made from fresh grapes”. It is the result of shifts in climate and the skills of each grower; its character changes from year to year. The terroir where the grapes grow is also a determining factor since, for any given grape variety, this can change the character of the wine.
Vinification is the name for the transformation of the grape or grape juice through fermentation. The term covers all of the actions carried out as part of this transformation. Fermentation is the transformation of sugar in the raisin into alcohol thanks to the work of yeast. Maturing takes place and involves all the actions that lead a wine from its youth to its development as a fully mature wine.
It doesn’t matter if the grape is black or white – the pulp is always translucent. When we press it, it immediately gives white juice, or several hours later pink juice, and after several days, red juice. With the first, white, juice, fermentation provides a white wine. The skin of the grape – called the pellicule in French – holds several aromatic substances that dissolve in the juice during vinification. The length of time of maceration during fermentation varies determines the colour of the wine. The shorter the maceration time, the lighter the colour.
Once they are harvested, white and red grapes are destemmed at the cellar; in other words the grapes are removed from their bunches and sent to the presses. After pressing, the white juice that is obtained is stored in tanks for an initial cleaning by decanting. During this stage the juice becomes clear. Fermentation follows: sugar is transformed into alcohol. The lees are then formed by the yeast’s activity. This is followed by malolactic fermentation, which occurs because of the work of bacteria. This process softens the natural acidity that is initially found in grape juice, providing suppleness and roundness to the wine. The wine becomes completely transparent after several months. Once it is filtered it can be bottled.
Rosé wine is made by macerating for a few hours the dark skins of grapes in the berry’s juice. La Cave de Genève, for its rosé wines, uses the direct pressing method, which lets the substances in the skin enrich the colour of the juice while also providing structure and aromas. For this kind of wine, fermentation is usually carried out in stainless steel tanks.
The skins of dark grapes must macerate in their juices for several days to several weeks in order for the wine to become red. After harvesting them, the grapes are destemmed, then sent directly to the fermentation tanks, which hold the skins and juice. The must is acted upon by the yeast and begins its fermentation phase: the sugar is transformed into alcohol. The wine that results some 10 to 15 days later is drawn from the fermentation tanks and stored in other tanks. The marc (the solid materials that are left in the fermentation tank) is sent to the press to extract the “press wine”, whose colour and tannins are very concentrated. This wine may later be blended with the first to reinforce the main wine’s structure. Malolactic fermentation takes place during vinification. The type of wine sought determines if it will be matured in stainless steel tanks or French oak barrels from 10 to 12 months. The wood gives the wine roundness and tannins that allow longer aging. When the wines are matured, the wines from barrels and/or tanks are blended, filtered, then bottled.
The process of making sparkling wine is natural – contrary to much popular belief. The wine at the outset, or “base wine”, is vinified traditionally. Secondary fermentation follows. In a hermetically sealed tank, sugar and yeast are added to the base wine to start the alcoholic fermentation. As the sugar in the alcohol ferments it produces a large amount of carbonic gas; since it cannot escape it dissolves in the wine. When the secondary fermentation is completed the wine is cooled down for several days, which allows optimal solubilization of the gas – giving birth to the fine, delicate bubbles which have made the name of our Baccarat line, known for its fresh and intense aromas.