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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 obviously 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.〔 ==History== There are indications that frozen grapes were used to make wine in Roman times.〔(Wein-Plus Glossar: Eiswein ), accessed on January 22, 2013〕 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.〔(Wein-Plus Glossar: Martial ), accessed on January 22, 2013〕 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. It is believed that the first post-Roman ice wine was made in Franconia in Germany in 1794.〔 Better documentation exists for an ice-wine harvest in Dromersheim close to Bingen in Rheinhessen on February 11, 1830. The grapes were of the 1829 vintage. That winter was harsh and some wine growers had the idea to leave grapes hanging on the vine for use as animal fodder. When it was noticed that these grapes yielded very sweet must, they were pressed and an Ice wine was produced.〔 It should be noted that sweet wines produced from late harvested grapes were well-established as the most valued German wine style by the early 19th century, following the discovery of Spätlese at Schloss Johannisberg in Rheingau in 1775, and the subsequent introduction of the Auslese designation. These wines would usually be produced from grapes affected by noble rot. Thus, Eiswein is a more recent German wine style than the botrytised wines. Throughout the 19th century and until 1960, Eiswein harvests were a rare occurrence in Germany. Only six 19th century vintages with Eiswein harvests have been documented, including 1858, the first Eiswein at Schloss Johannisberg.〔 There seems to have been little effort to systematically produce these wines during this period, and their production was probably the rare result of freak weather conditions. It was the invention of the pneumatic bladder press which made the production of ice wine practical and led to a substantial increase in the frequency and quantity of production. 1961 saw the production of a number of German ice wines, and the wine increased in popularity in the following years.〔Freddy Price, ''Riesling Renaissance'' Mitchell Beazley 2004, pg. 19 ISBN 1-84000-777-X〕 The production has also been assisted by other technological inventions in the form of electrical lighting driven by portable generators (to assist harvest in the cold hours of early-morning darkness, before the sun rises and the grapes can thaw), remotely controlled temperature alarms (after a re-thawing the grapes will spoil very quickly since ice crystals will have destroyed the cell walls; thus the harvest has to be completed within a few hours on the first morning that is cold enough) and plastic films that are used for "packaging" the vines during the waiting period between ripeness and first frost, in order to protect the ripe grapes from being eaten by birds. In Germany in the early 2000s, good ice-wine vintages have been less common than during the 1980s and 1990s. Many wine-growers cite climate change as a cause, a position supported by a study conducted by the Geisenheim Institute. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ice wine」の詳細全文を読む スポンサード リンク
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