Fermentation is the process in which must sugar is converted into alcohol by yeasts
Those responsible for the alcoholic fermentation of wines are Saccharomyces. Grape juice contains high levels of sugar naturally. These sugars are transformed into alcohol and carbon dioxide. Natural fermentation can produce wine with alcohol of up to 16%.
The temperature during the alcoholic fermentation process should be controlled, since if it increases by a certain level it will cause the death of the yeasts, spoiling the wine and causing the appearance of strange odors. Therefore, normally, the alcoholic fermentation process is done in stainless steel or wood tanks, which have a temperature control, which allows the musts to be cooled during fermentation.