An essential requirement for a high quality wine is a controlled one fermentation, At the alcoholic fermentation will the in grape contained sugar in alcohol converted, which also creates various primary and secondary by-products. These are, for example, the positive ingredients for the taste of the wine ester and glycerin, Due to fermentation errors, the various chemical substances, depending on their concentration, can have a negative impact on the quality of the wine. Most PGar errors can be corrected by appropriate must treatment be avoided. For example, are common sulphurize of grapes and a properly dosed degumming des Mustes (removal of sediment). Fermentation stagnation can be due to physical (low fermentation temperature), microbiological (beginning BSA during fermentation) or chemical (low nitrogen content in the must). The standstill is expressed by very typical signs. The carbon dioxide Education ceases, the temperature drops and the yeasts start to settle on the ground.
Uncleaned or poorly clarified musts ferment stormily (if necessary too quickly) under strong heat, too strongly clarified musts possibly too slowly. According to the yeast used, the optimal fermentation temperature must be observed. From 35 to 40 ° Celsius ( Versiede -Temperature) the yeast is poisoned and the fermentation gets stuck. This can lead to loss of aroma and wine error vinegar sting to lead. Cider of higher grade can be poor nitrogen be, which leads to a weak yeast multiplication. The same effect has too high a content of sulphurous acid as well as residues of Pesticides, The alcohol and sugar content and the yeast status must be checked before any measures are taken. The stagnation can be remedied by raising the temperature with must warmers and adding pure cultivated yeast. Above a certain alcohol content (about 12% vol) and below 10 g / l residual sugar it is relatively difficult to start a fermentation in progress.