Term for an unfermented and mean sulfur dioxide or filtration made sterile grape, This is added to the already fermented wine, especially in cooler wine-growing regions, in order to acid to mitigate and Residual sugar content to increase. The must is at best the same from which the wine was made. That is why part will be before the start fermentation deducted, the sterile or completely free of yeasts must be in order to exclude post-fermentation. Before adding to the wine, it must desulphurized become.
The term sweet reserve is also used in part for the sweetening process itself. The required amount can be determined using the so-called Cramer's cross can be calculated or (much easier) using sweetening tables. In Austria is a sweetening in any form (including through a sweet reserve) at the quality level cabinet and for everyone Prädikatsweine forbidden. In Germany the addition of a sweet reserve is also permissible for premium wines, but this is only used by individual producers.