A prerequisite for a high quality wine is a controlled one fermentation, At the alcoholic fermentation
becomes the one contained in the must sugar
transformed by very complex processes and different primary and secondary by-products. These are, for example, the positive components of the taste of the wine ester
, Due to fermentation errors, the various chemical substances can negatively influence the quality of the wine depending on their concentration. Most problems or fermentation errors can be caused by appropriate must treatment
be avoided. Usual are for example sulphurize
of grapes and a properly dosed degumming
of the must (removal of debris). A fermentation stagnation can have physical (low fermentation temperature), microbiological (incipient BSA during fermentation) or chemical (low nitrogen content in must) reasons. The standstill is expressed by quite typical signs. The formation of carbon dioxide stops, the temperature drops and the yeasts begin to settle on the ground.
Uncleared or poorly clarified musts ferment with strong evolution of heat stormy (if necessary too fast), too sharply clarified musts may be too slow. According to the used yeasts
the optimum fermentation temperature is to be observed. From 35 to 40 ° Celsius (Versiede temperature), the yeast is poisoned and the fermentation gets stuck. This can cause the loss of flavor and the wine error vinegar sting
lead (see under Versieden
). Must of higher predicates can be poor nitrogen
be, resulting in too weak yeast multiplication. The same effect has too high a content sulphurous acid
as well as residues of pesticides. Alcohol and sugar content as well as the yeast status should be checked before possible measures. A removal of the stagnation can be done by raising the temperature by means of must warmer and adding pure culture yeasts. From a certain alcohol content (about 12% vol) and less than 10 g / l residual sugar
It is relatively difficult to restart a bush-fed fermentation.