A prerequisite for a high quality wine is a controlled one fermentation, At the alcoholic fermentation will the im grape contained sugar in alcohol which also produces various primary and secondary by-products. These are, for example, the positive components of the taste of the wine ester and glycerin, Due to fermentation errors, the various chemical substances can negatively influence the quality of the wine depending on their concentration. Most PG errors can be caused by appropriate must treatment be avoided. Usual are for example sulphurize the grapes and a properly dosed degumming of the must (removal of debris). A fermentation stiffener may 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 carbon dioxide Formation stops, the temperature drops and the yeasts begin to settle on the ground.
Uncleared or poorly clarified musts ferment under strong heat stormy (if necessary too fast), too sharply clarified musts may be too slow. According to the yeasts used, the optimum fermentation temperature must be taken into account. From 35 to 40 degrees 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 to lead. 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 any measures can be taken. The stoppage can be remedied by raising the temperature with the must warmer and adding selected yeasts. From a certain alcohol content (about 12% vol) and less than 10 g / l residual sugar It is relatively difficult to restart a bushy fermentation.