THE BEGINNING OF THE FERMENTATION
Once made the grapes selection and introduced into the fermentation tank, all starts thanks to a small living things that are called yeast that are actually cells having its own life and although they are microscopic, they have everything necessary to live and reproduce. Yeasts are found in grape skin, and once the grapes are broken and are surrounded by grape juice which contains sugars, the yeasts start to metabolize these sugars through the cell wall, then they reproduce themselves in an exponential way and its population increases while they have sugars to eat , producing at the same time the wine ethanol as well as carbonic gas.
Before to start the fermentation, if we can manage to keep the must (grape juice) cold, the yeasts can not start the fermentation inmediately, so we can work with the grapes by moving them extracting color and aromas from their skins, which is essential to make good wine. Then,we have to avoid the yeast begin to ferment very quickly once into the tank since we would not obtain the same results.
To make the wine Camino Soria we maintain the must with the skins almost a week before starting to ferment, moving the skins in contact with the must to extract impressive colors and aromas. Other operation we made is to take must of the bottom of the tank and threw it over, serving to unify all of the paste-mixture forming the skins and must.
Thanks to modern cooling systems we can keep the cold to avoid the fermentation to start immediately, and once it begins, we can maintain the temperature under a determinate quantity in such a way that the fermentation is going smoothly. For this we circulate cold water through a pipeline that is in the walls of the tanks, thus avoiding getting too hot. But what causes the heat appearing, which comes out? well, again the cause is yeast, consuming sugar produced several things, some are good for our purpose of making wine ... as ethanol (the alcohol in wine), but also produce carbon dioxide, CO2, and heat, much heat.
Why is it not good to do the fermentation with excess heat? That is because the heat stresses the yeasts and in that situation they can not end properly the fermentation, leaving unfermented sugars, which could cause problems to the wine, so the temperature should be maintained below certain levels. In red wines, it is recommendable to make the fermentation below 28 degrees Celsius so that the yeasts can consume all the sugars slowly and the fermentation can be completed successfully.