Winegrowers Supplies  -  Sweetening of wine at bottling time

Sweetening of wine can be carried out by the addition of grape must (unfermented grape juice, also known as sweet reserve or Süss-reserve), but not by the addition of sugar. Concentrated grape must or rectified concentrated grape must may be used if a wine has not been enriched.
Süss-reserve is permitted to contain up to 1.0 %vol alcohol.

There are other European Commission legal requirements for addition of Süss-reserve, which have changed from the 2009 vintage:-

1) The total alcoholic strength of a wine may be increased up to a maximum of 4 %vol.
In fermented or bottled wine: total alcohol = actual alcohol plus potential alcohol content of any unfermented sugars. The maximum increase of 4 %vol is a further addition of about 67 grams/litre of residual sugar, which would make an extremely sweet tasting wine.

It is essential to bear in mind that for the sweetened wine - the actual alcoholic strength by volume (%vol) of wine in bottle shall be at lowest 8.5 %vol. When adding Süss-reserve it is this which limits the maximum amount that can be added.

2) White wines should be only be sweetened with white Süss-reserve.
Rosé and red wines should be only be sweetened with red Süss-reserve.

3) For Quality Wine the addition of Süss-reserve is restricted to products originating in the same Quality Wine region.