While tripping through Germany this last summer with my family we had the fortune of staying in a small winery in the tiny town of Zell. Zell lies in the Mosel Valley region, famous for the production of the sweet white wine called Riesling. The owner of the winery was kind enough to give us a tour of the wine cellar and let us taste a variety of homemade Rieslings. Toward the end of the tasting he proudly pulled out a small bottle of his award-winning eiswein. Since none of us had heard of eiswein before, we asked him for an explanation. After much confusion with our pathetically limited German and his limited English, we discovered that it was a special type of wine made from crushed and fermented frozen grapes.
Intrigued, we bought a bottle and ceremoniously drank it on Christmas Eve. The first thing I noticed was that the eiswein had a very rich golden color and looked somewhat dense, almost syrupy, in the glass. It was extremely sweet, almost like condensed white grape juice splashed with a hint of white wine. The sweetness was balanced by the acidity of the wine and a distinct musty smell and flavor. It was thoroughly enjoyable, but best in small doses.
After doing a bit of research, I found that eiswein literally translates to "ice wine" in German. It is made from grapes that have completely frozen on the vine after the first major freeze of the year. While most wine grapes are harvested during September and October, grapes for eiswein are left on the vine until December or even January. After a good freeze the grapes are quickly picked before sunup to avoid thawing. The frozen grapes are then transported to an outdoor press and gently crushed. The water present in the grapes is frozen and does not pass through the press, but the grapes also contain a highly concentrated grape juice that does not freeze due to an excessive amount of sugar. (Ouroboros notes: Since the grapes have been on the vine until the first frost, they are overripe, and rather high in sugar already.) This juice is extracted from the grape and is slowly fermented to make eiswein. Because the juice is so concentrated eiswein is extremely sweet and flavorful, with a fair amount of acid and musty flavors from the grapes to balance the sweetness. The wine is roughly 26-30 percent sugar depending on the region and type of grape.
Eiswein was discovered when the winter frost came early in the late 1700s in the regions that eventually became Germany. The frost caught the peasants who were growing the grapes by surprise and froze the grapes on the vine. Rather than throwing away the grapes, the peasants decided to try and make wine anyway, and eiswein was born. Today, Germany is best known for eiswein, but it has also developed a reputation in Austria and Canada. There are strict regulations that must be met before a wine can be labeled "eiswein", including requirements for a specific percentage of sugar and acid and for the time and method of harvesting the grapes. Riesling and Vidal Blanc grapes are traditionally used to make eiswein due to their late season and high sugar content. True eiswein must also be made from grapes that have naturally frozen on the vine, never from artificially frozen grapes.
Eiswein is a rather rare type of wine and is most similar to a Riesling or the German wines Beerenauslesen and Trockenbeerenauslesen. Since so little actual liquid is obtained from the frozen grape many more grapes are needed to make a bottle of eiswein compared to normal wines. Eiswein tends to be more expensive as a result, often running several hundred dollars for a small bottle.
Eiswein is very refreshing, but probably a tad too sweet for some tastes and will probably be overwhelming with a meal. Eiswein makes an excellent chilled dessert wine paired with a subtle dessert or simply nuts and cheese. It is also very nice served on its own after the meal as a digestive.
http://www.ontariograpes.com/icewine.html
http://www.wineontheweb.com/features/icewineoreiswein/icewineoreiswein.html
http://www.islandnet.com/~see/weather/almanac/arc2003/alm03jan2.htm
http://staging.foodtv.com/wine/eiswein/0,6923,,00.html