Ice wine (or
icewine;
German Eiswein) 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, allowing a more concentrated grape
must to be
pressed from the frozen grapes, resulting in a smaller amount of more concentrated, very sweet wine. With ice wines, the freezing happens before the
fermentation, not afterwards. Unlike the grapes from which other dessert wines are made, such as
Sauternes,
Tokaji, or
Trockenbeerenauslese, ice wine grapes should not be affected by
Botrytis cinerea or
noble rot, at least not to any great degree. Only healthy grapes keep in good shape until the opportunity arises for an ice wine harvest, which in extreme cases can occur after the New Year, on a northern hemisphere calendar. 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".