The course of the first phase: turbulent fermentation.
One to two days after the juice has been degummed and combined with the active "mother yeast", prepared from pure breed yeast, fermentation is in full swing, where the correct temperature is important (should be not lower than 15 ° C and not higher than 25 ° C). There is a murmur, and if the fermentation takes place in a glass balloon, you can also see bubbles of carbon dioxide floating upwards. A foam cap forms on the surface of the fermenting liquid, and on closer observation it can be stated, that it is not stationary, but it moves in a circle in a vertical plane in two opposite directions, similar to the home robot's foam beating attachments, they move horizontally.
To see it, only one larger clump of sediment should be observed: it rises slowly along the outer wall of the vessel, goes towards the center, and just below the surface of the fluid it is dragged downwards at an increased speed. Thus, a complete replacement is carried out in the setting.
Smaller knobs, about the size of a glass gander, shakes from time to time; however, this cannot be done with larger barrels, because they are too heavy. It is not necessary anyway, because elevated fermentation temperature increases the speed of fluid circulation.
The lower the sugar content of the juice (in the degrees of Ochsle), the less work the yeast cells have and the faster the fermentation process is completed. Duration of fermentation of weak table wines is approximately one week, stronger table wines (80°)-14 days, and dessert wines – couple months. Due to this, no more precise data can be provided, that conditions vary from year to year, region, kind of fruit, and also related to the preliminary preparation and subsequent treatment of the wine.
Fermentation takes place without outside help and ends by itself.
The winemaking is not without reason: “It's easier to get fermentation started, than to disturb her!"As long as the water is bubbling in the fermentation tube, fermentation is still in the first, turbulent phase. During this time, nothing else remains, as soon as you wait and take a sample of the fermenting must from time to time. You can at least get to know a little bit now, what flavor the future wine will have. But such an assessment is only possible on the basis of experience, it is very difficult to describe in a book!
The end of turbulent fermentation can be recognized by this, that carbon dioxide travels very sluggishly through the tube and gurgles only a little.
• For amateur winemakers, who have a cellar full of fermenting wine (just like me), the following considerations are important: Carbon dioxide formed during fermentation is very dangerous from a certain concentration! Because it is heavier than air, it gathers low to the ground. If the entrance to the basement is situated high up and therefore only provides little air exchange, it is when in the basement you are necessarily inhaling an odorless, dangerous gas! Therefore, care should be taken to ensure sufficient ventilation, before entering it, you should light a candle. If the candle goes out, you must leave the basement immediately. Formerly, when most of the wine cellars were placed underground, the winemaker did not go down to any of them without his "light of life". If the candle has gone out, it was known, what to do.
• The turbulent fermentation takes place without our help. The fermenting wine is left to its own fate.