Name for a special type of wine produced from frozen grapes. There must have been an "ice wine" already in ancient times, because the Roman poet Martial (40-102) reports of winegrowers who brought in frost-starved grapes in November. Also in the 1st century, the scholar Pliny the Elder (23-79) described certain grape varieties: "They are not harvested until it has frozen". This indicates that ice wine was produced quite deliberately and not just by chance. Later, however, this method of harvesting and vinification seemed to have been forgotten. It is said that the production of ice wine was then rediscovered in France towards the end of the 18th century. Similar to the Trockenbeerenauslese, the phenomenon was not planned specifically in the beginning, but most likely occurred by chance when a very early frost attack surprised the wineries during the actual main harvest.
The first ice wine harvests in Germany are said to have taken place in Franconia in 1794. The first documented ice wine was harvested on 11 February 1830 from grapes of the 1829 vintage in Dromersheim near Bingen in the Rheinhessen wine region. There was an extremely cold winter and some winegrowers had the idea to leave the grapes hanging to feed the animals. When it was discovered that the grapes contained very sweet must, they were pressed. In this regard, a monument to Eiswein was even erected in Dromersheim (see picture above right). For the 19th century, however, there are only six years documented in writing in Germany during which ice wine could be produced. That was the mentioned vintage 1829, as well as the vintages 1846, 1858 (at Johannisberg Castle), 1875, 1880 and 1890.
Today it is considered a sweet wine speciality of the northern wine-growing countries, because only in these latitudes the necessary climatic conditions prevail. But even here, this only applies to those areas where relatively early and severe frost sets in. In Germany and Austria, although not every year, such conditions are present time and again. In both countries, Eiswein is a special type of wine within the quality wine category Prädikatswein. An excellent Icewine culture also developed in Canada (Ontario) from the mid-1970s onwards, which was initiated by the Austrian-born Dr. Karl Kaiser (1941-2017) at the Inniskillin winery. The production is extremely complex and risky and cannot be planned. In addition, the quantity harvested is only a fraction of a conventional wine, which explains the relatively high prices. The must weight in Germany and Austria must be at least equal to a Beerenauslese. However, Eiswein can only be made from fully ripe grapes; if the grapes are frozen in an unripe state, then all the grape juice is frozen and no higher sugar concentrate can be pressed.
An absolute prerequisite for the grape harvest is frost. The grapes, which are as healthy as possible and usually not affected by Botrytis, must be left on the vine until the frost sets in. This is usually the case from the month of November at the earliest, but can also be the case towards the end of January of the following year. The outside temperature must drop to at least minus 7 °Celsius or colder for at least five hours, or at best longer, and remain there. The sweet must with the extracts has a lower freezing point than water. However, the extractive substances in the berries prevent the water from freezing at normally 0 °Celsius. The lower the temperature, the better the water molecules freeze and the pure must extract can be pressed. The ideal time for the grape harvest is usually early morning.
The grapes must then be pressed as quickly and completely as possible, which means without destemming. During this process, the concentrated grape juice with all the ingredients rich in extract and sugar is separated from the ice crystals. Only this concentrated must runs off, the ice (water) remains and is separated with the marc. This is checked on site by an official testing body. The process is very slow and takes several hours, during which time the press cake must not thaw or only slightly thaw, both for legal and qualitative reasons (decrease in must weight). There are attempts to produce similar products by freeze concentration. In 2001, the European Union approved the protected designation Icewine for the European market, thus opening the Canadian market to ice wines from Germany, Austria and other EU countries.
All work, techniques and measures in the vineyard during the vegetation cycle can be found under vineyard care. Complete lists of the numerous vinification measures or cellar techniques, as well as the types of wine, sparkling wine and distillate regulated by wine law can be found under Vinification. Comprehensive wine law information can be found under the keyword wine law.
Grapes frozen: By Dominic Rivard from Bangkok,
Thailand - icewine grapes, CC BY-SA 2.0, Link
Monument: From MSeses - Own work, CC BY-SA 3.0, Link
Bocksbeutel: Citizens' hospital
Grape: © DWI (German Wine Institute)
Ice wine harvest: Brothers Nittnaus