Thicker skinned grapes and grapes with more seeds need extra time on the vine. The average red grapes need approximately 90-120 on the vine. Once the brix is at the desired amount 26-28 Brix (sugar measurement), they are harvested and crushed. The juice is then left with the skins and the seeds during fermentation so that the juice gets the color of the skins, as most grapes have clear pulp.
Once fermentation is completed (or sometimes during), a secondary fermentation, malolactic fermentation (MLF), may occur to soften the tannins, which gives the wine a velvety texture. It can depend upon the winemaker and the house style if this occurs or not. (If not, then the wines would need to be either heated in a pasteurization method or ferment cold to prevent he secondary fermentation). During fermentation, the grapes are punched down or over the cap. The skins and seeds float to the top and the wine needs to move over the skins to extract the maximum amount of color. This often happens either in macrobins or in tanks without being covered to encourage oxygen flow. Once fermentation is complete, the wine is pressed and then the tank or barrels are completely sealed to prevent oxygen. Every month the barrels must be topped off to prevent oxygen from getting into the wine. Every couple of months, the wine is emptied into a blending tank and the barrels are cleaned to remove must or sediment. Some winemakers choose to stir the lees (skins, seeds and yeast) back into the wine to create a richer wine, albeit when this happens, there will often be residue around the punt of the bottle).
There are other techniques that may be used, to create different flavors in the wine such as carbonic maceration. In this process the grapes are put in a tank and the tank is filled with CO2 which prevents oxygen during fermentation. The weight of the grapes causes the crushing, which results in soft tannins but changes the expression of the fruit.
Sometimes whole cluster pressing is done without crushing the grapes first. In this technique there is less contact with the skins so the color is lighter. The stems may add a light white pepper note to the wine with lighter tannins (described as the cat tongue or tea back feeling on your tongue).
Another trick that wine makers have up their sleeve, is cold maceration (also known as cold soaking that may last as long as 2-3 weeks). In some wineries there is a room that may be a bit colder than the rest or sometimes dry-ice is added to the macro bins. This slows or prevents the yeast from eating the sugar, slowing or preventing fermentation. Sometimes this is done so that more grapes may ferment together as the grapes come in at different times. Other times this is done for more color extraction (allowing the juice to be in contact with the skins for a longer amount of time) or to protect the delicate aromas of some grapes that may dissipate with heat.
Red wine is often aged to soften the tannins as the wine gets smoother over time. However, with new barrels, the flavor can be intense and time softens the intensity of new oak profiles as well. Different types of oak add different flavors to the wine. Blending is then often done to help balance acidity, tannins, fruit profile and oak notes. Wines are allowed to be labeled as single varietal if there is at least 75% of the base wine in the bottle. A lot of artistry happens with or without the knowledge of the consumer. Hence why every bottle is a work of art and is forever evolving with time.
