is a type of dessert wine produced from grapes that have been frozen while still on the vine. The sugars and other dissolved solids do not freeze, but the water does, so the result is a concentrated, often very sweet wine. In the case of ice wines, the freezing happens before the fermentation, not afterwards. Unlike the grapes from which other dessert wines, such as Sauternes, Tokaji, or Trockenbeerenauslese, are made, ice wine grapes should not be affected by Botrytis cinerea or noble rot. Only healthy grapes keep in good shape until the opportunity for ice wine harvest, which may be in the next calendar year. This gives ice wine its characteristic refreshing sweetness balanced by high acidity. When the grapes are free of Botrytis, they are said to come in "clean".