Ice wine

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".

Ice wine production is risky (the frost may not come at all before the grapes rot or are otherwise lost) and requires the availability of a large enough labour force to pick the whole crop within a few hours, at a moment's notice, on the first morning that is cold enough. This results in relatively small amounts of ice wine being made world-wide, making ice wines generally quite expensive.

Ice wine production is limited to that minority of the world's wine-growing regions where the necessary cold temperatures can be expected to be reached with some regularity. Canada and Germany are the world's largest producers of ice wines. About 75 percent of the ice wine in Canada comes from Ontario.

There are indications that frozen grapes were used to make wine in Roman times.Pliny the Elder (AD 23 – 79) wrote that certain grape varieties were not harvested before the first frost had occurred. The poet Martial recommended that grapes should be left on the vine until November or until they were stiff with frost. Details as to the winemaking and description of these wines are unknown. It cannot be completely ruled out that the descriptions refer to dried grape wines, a common style of wine in Roman times, where the raisin-like grapes were harvested late enough for the first frost to have fallen. In either case, the method seems later to have been forgotten. Wine from Chiomonte in the Val di Susa was popular in Roman times and this town still today produces one of Italy's few ice wines.

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