Ледяное вино: технология производства и история

A type of dessert wine produced from grapes that have been frozen while still on the vine

Icewine (or ice wine; 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 for a more concentrated grape juice to develop. The grapes' must is then pressed from the frozen grapes, resulting in a smaller amount of more concentrated, very sweet juice. With icewines, the freezing happens before the fermentation, not afterwards. Unlike the grapes from which other dessert wines are made, such as Sauternes, Tokaji, or Trockenbeerenauslese, icewine 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 icewine harvest, which in extreme cases can occur after the New Year, on a northern hemisphere calendar. This gives icewine its characteristic refreshing sweetness balanced by high acidity. When the grapes are free of Botrytis, they are said to come in "clean". This results in a very complex and sweet wine. Much icewine is made from the grapes Riesling, Vidal, Cabernet Franc and Cabernet Sauvignon, but there is also icewine made from Shiraz, Merlot, Sangiovese and others. Icewine 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. The grapes for icewine must only be harvested when they are frozen naturally and the temperature must be 8 C (20°F) or below when they are picked. This results in relatively small amounts of ice wine being made worldwide, making icewines generally expensive. Icewine 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 is the world's largest producer of icewine, producing a greater volume of icewine than all other countries combined with Ontario producing over 90% of Canada's icewine, followed by Germany.

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. It is believed that the first post Roman icewine was made in Franconia in 1794. The production has been assisted by other technological inventions in the form of electric lighting driven by portable generators (to assist harvest in the cold hours of early morning darkness, before sunrise and the grapes thaw), and remotely controlled temperature alarms. After re thawing, the grapes will spoil quickly since ice crystals destroy cell walls. Thus, the harvest must be completed within a few hours on the first morning that is cold enough. Plastic films are used for "packaging" the vines during the waiting period between ripeness and first frost to protect the ripe grapes from being eaten by wildlife.

Icewine was first produced in the Okanagan Valley of British Columbia by German immigrant Walter Hainle in 1972. This icewine was the result of an early and unexpected frost, and yielded of wine, which Hainle originally did not intend to sell, although he did so in 1978. In 1983, Niagara based wineries Inniskillin's and Reif Estate Winery, as well as Hillebrand, and Pelee Island Winery, two wineries with Austrian winemakers situated in another part of Ontario, all left grapes on their vines in an attempt to produce icewine. Inniskillin and Reif lost their entire crop to hungry birds, while Hillebrand and Pelee Island were able to harvest a minuscule amount of frozen grapes. In 1984, Inniskillin winery was the first winery in Canada to produce icewine for commercial purposes, produced in 1984 under the direction of the winery's Austrian born co owner Karl Kaiser, often being mentioned as Canada's first icewine as they were "naturally frozen on the vine". In 2001, the EU allowed the importation of Canadian icewine hence recognizing the standard equivalency.

In contrast to most other wine producing regions, Canada, particularly the Niagara Peninsula, consistently undergoes freezing in winter and has become the world's largest icewine producer. As a result, Canada produces a greater volume of icewine than all other countries combined. with wineries in Ontario producing approximately of ice wine in 2016. However, it is also produced in all other wine growing provinces of Canada, including British Columbia, Quebec, and Nova Scotia. Icewine production is regulated by the VQA in the provinces of British Columbia and Ontario. If the sugar level in the grapes measures less than 35° Brix, then they may not be used for icewine, a minimum considerably higher than that of German Eiswein. Though Pelee Island Winery and Hillebrand were Canada's first commercial icewine producers, starting production in 1983, Inniskillin Wines is considered the most widely known Canadian icewine producer as the first Canadian winery to win a major international award, the Grand Prix d’Honneur at 1991 Vinexpo in France, with their 1989 Vidal Icewine (which was technically an illegal import into the EU Pillitteri Estates Winery has emerged in the 2000s as the world's largest estate icewine producer. In November 2006, Canadian producer Royal DeMaria released five cases of Chardonnay icewine with a half bottle price set at C$ 30,000, making it the world's most expensively priced wine.

The most famous (and expensive) icewines are German Eiswein, but icewine is also made in European countries such as Austria, Croatia, Czech Republic, Denmark, France, Georgia, Hungary, Italy, Lithuania, Luxembourg, Moldova, Poland, Romania, Slovakia, Slovenia, Spain, Sweden and Switzerland at least in smaller quantity. Eiswein is part of the Prädikatswein quality category in the German wine classification. The French language term Vin de glace is part of the wine classification in Luxembourg, but not in France, but is sometimes found on the rare bottles of icewine produced in Alsace. In most of France, the climate is too warm for icewine production.

The Furano region of Central Hokkaido, Japan, produces an icewine each winter at the Furano Winery. Because such a small amount can be made each year, it is produced in limited batches and sold only at the cellar door, 3.3 kilometres from Furano Station. The Furano Wine icewine is produced only in red.

Northern Michigan wineries continue to follow the German laws that govern what wine qualifies as icewine, which dictates that icewine must be picked only when the grapes are frozen on the vine. In 2002, six Michigan wineries produced over 13,000 half bottles of ice wine, a record at that time. A growing number of wineries near Lake Erie, especially in Pennsylvania, New York, and Ashtabula County, Ohio, also produce icewine. The US law for icewines specifies that grapes must be naturally frozen. The TTB (Tax and Trade Bureau) regulations state that "Wine made from grapes frozen after harvest may not be labeled with the term 'icewine' or any variation thereof, and if the wine is labeled to suggest it was made from frozen grapes, the label must be qualified to show that the grapes were frozen postharvest."

In Austria, Germany, the US, and Canada, the grapes must freeze naturally to be called icewine. In other countries, some winemakers use cryoextraction (mechanical freezing) to simulate the effect of a frost and typically do not leave the grapes to hang for extended periods as is done with natural icewines. Cryoextraction is the process by which grapes are frozen with refrigeration and pressed. Winemakers subject grapes to temperatures around 20 degrees Fahrenheit (or −7 degrees Celsius), and press them while still frozen. Ice crystals remain in the press, while concentrated juice flows out. The resulting wine resembles ice wine. The process of freeze distillation is similar in its concentrating effects, although it occurs after fermentation. These non traditional wines are sometimes referred to as "icebox wines". An example is Bonny Doon's Vin de Glacière or King Estate's Vin Glace (made from Oregon Pinot gris grapes). German wine law entirely bans post harvest freezing methods, even if not labeled "Eiswein".

Typical grapes used for icewine production are Riesling, considered to be the noblest variety by German winemakers; Vidal, highly popular in Ontario, Canada; and the red grape Cabernet Franc. Many vintners, especially from the New World, are experimenting with making icewine from other varieties: whites such as Seyval blanc, Chardonnay, Kerner, Gewürztraminer, Muscat Ottonel, Chenin blanc, Pinot blanc, and Ehrenfelser, or reds such as Merlot, Pinot noir, and even Cabernet Sauvignon. Pillitteri Estates Winery from the Niagara on the Lake region of Ontario claim to be the first winery in the world producing Shiraz (Syrah) icewine with the 2004 vintage, Semillion, and Sangiovese in 2007. Icewines from white varieties tend to be pale yellow or light gold in color when they are young and can maderise (acquiring a deep amber golden color) as they age. The red varieties tend to have a light burgundy or even pink color like that of rosé wines, since the steeping of the skins in the pressed liquid typically used in red wine making is obviously not possible in ice wine production.

Even though it is normal for residual sugar content in icewine to run from 180 g/L up to as high as 320 g/L (with a mean in the 220 g/L range), icewine is very refreshing (as opposed to cloying) due to high acidity. (The titratable acidity in ice wine is almost always above 10 g/L.) Icewine usually has a slightly lower alcohol content than regular table wine. Some Riesling icewines from Germany have an alcohol content as low as 6%. Icewines produced in Canada usually have higher alcohol content, between 8 and 13 percent. In most years, icewines from Canada generally have higher brix degree (must weight) compared to those from Germany. This is largely due to the more consistent winters in Canada. Must with insufficient brix level cannot be made into icewine, and is thus often sold as "special select late harvest" or "select late harvest" at a fraction of the price that true icewine commands.