Synonym (also RS for short) for residual sugar; see there.
Term (also residual sweetness, RS) for the amount of sugar in the wine that is achieved by a natural end to fermentation or by stopping fermentation. The yeasts are removed, killed or at least strongly inhibited in their activity by various methods during winemaking. These include filtering the fermenting wine (removing the yeast cells), cooling to minus 3 to 2 °C (resting), sulphurisation, short-term heating to 75 °C or, for certain wines, the addition of pure alcohol or Spriten (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, as well as a small proportion of non-fermentable sugars (pentoses).
According to EU regulations and, in some cases, the different national wine laws, it is optional to indicate the name of a certain residual sugar content in the wine on the label. However, each country has the right to specify this as a mandatory labelling requirement under wine law.
The terms and quantities for still wines are shown in the following table, whereby the relevant wine law terms only begin with the line "dry". A tolerance limit applies because there may be uncertainties depending on the laboratory and measurement method. The sugar content may not deviate by more than 1 g/l from the indication on the label:
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Dr. Christa Hanten
Fachjournalistin, Lektorin und Verkosterin, Wien