Grapes should be harvested at their optimal physiological maturity. In red varieties this means when the tannins are noble (not astringent) and color pigments are at the center of the vacuole of the skin cells to maximize their extraction during fermentation. This is a relative new concept about 15 years old. The commercial maturity instead is based only on percent of sugar (Brix) and it has and still is the most used one, but with the global warming the two maturities do not coincide any more since 40-50 years ago. This is why the alcohol % of the wines, since then, have been gradually going up to the point that then the wines were perfect on the 12-13% level in Europe and now they are in the 14% while in Napa you find that most of the wines are in the 15-16 % level.
Red grapes are crushed and fermented (using different native commercial selected yeast strains) with the skins at different controlled temperatures in SS jacketed tanks depending on the variety of grapes and the style desired. Ethylene glycol is circulated in the jackets to cool the juice because from each Kg of fermented sugar is generated 22 Kilocalories that are partially carried away by the chiller compressor where the glycol circulates. Native yeasts are selected by specialized Industries from different growing areas so we use for example Syrah yeast isolated in the area of production of this grape variety in Southern France where it is cultivated. And this is the same for other areas of production in Italy, Spain, etc.