Also known as residual sweetness (RS), the amount of sugar in the wine that is achieved by a natural end to fermentation or by a targeted stop. In this process, the yeasts are removed, killed or at least very strongly inhibited in their activity by various methods or means. These include, for example, filtering the fermenting wine (removing the yeast cells), cooling it down to minus 3 to 2 °Celsius (immobilisation), adding sulphur, heating it for a short time to 75 °Celsius or, in the case of certain wines, adding pure alcohol (killing).
The residual sugar consists mainly of the sugar type fructose (fruit sugar), because glucose (grape sugar) is converted more quickly into alcohol and carbon dioxide, and to a small extent of non-fermentable sugars (pentoses). The remaining sugar content can be indicated on the label in the form dry, semi-dry, feinherb, medium sweet or sweet, as regulated by wine law. There are further, country-specific designations which, however, have no significance under wine law. The formerly common designation diabetic wine is no longer permitted for consumer protection reasons.
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