As with the white wine grapes, the red wine grapes are crushed and de-stemmed as soon as possible after harvest. At this point, the product may be cooled or heated, sulfur dioxide treated or left as is. If cooled, the desire is usually to slow fermentation in order to increase fruit flavors or to extend contact with the skins, which increases the intensity of color. If heated, fermentation may be accelerated thus shortening the time to market as in the Beaujolais Nouveau which is released as soon as it is clarified and stabilized.
Sulfur dioxide may be added upon completion of the crushing and stemming process. This is done in order to kill natural or unwanted yeasts in the macerated product. After 24 to 48 hours the desired yeasts are then added to the macerated product and fermentation is on its way.
The duration of fermentation and skin contact is dependent upon the type of wine being made or the wine maker&Mac226;s intent. For example, blush wines may be pressed at once, thus eliminating or at least reducing color saturation. At higher temperature levels fermentation can be completed in as little as four days. Skin and seed contact then becomes a matter of increasing color intensity.
During red wine fermentation, the must or mass of crushed grapes floats to the surface. This cap, as it is called, is pushed down several times a day or may be submitted to a technique called pumping over, which is a more mechanical method requiring less labor.
Once the wine maker is satisfied that his criteria has been met, the macerated product is pressed to remove the seeds and skins. This pressed wine is then ready for inoculation with nutrients to exacerbate malolactic fermentation. Malolactic fermentation is a function of bacteria in the absence of air (anaerobic,) enhancing the bouquet and adding complexity to red wines.
Barrel ageing ensues with periodic racking to remove sediments from the wine. Barrel ageing can last for one to three years depending on the wine maker&Mac226;s intent. Once aged these red wines can be filtered, fined, stabilized and bottled. Some red wines are left unfiltered and un-fined which according to some winemakers adds to the complexity and big mouth feel of the product. Bottle ageing follows, which settles the wine in its new home adding to its smoothness