Ice wines are made from frozen grapes. As the story goes, the discovery of ice wine dates back to the winter of 1794 when producers in Franconia, Germany, had frozen grapes on their hands and decided to go forward with the pressing. When they finished, they were startled by the high sugar concentration of the juice.
When grapes freeze, the first solid to form is ice. As the grapes are crushed, the ice is left behind with the other solids — the skins and seeds. This leaves behind a very sweet juice. For example, if the sugar content of the juice is 22 percent when pressed normally, it would be 50 percent or more after freezing and pressing.
In order for the grapes to freeze, they have to be left on the vine well into the winter months, when freezes of 18 degrees Fahrenheit are typical. Waiting for them to freeze can be risky business. If the weather doesn't cooperate and the grapes don't freeze, a grower can lose his entire crop.
Harvesting takes place by hand in the early (and necessarily cold) morning hours when acidity levels are at their highest. Pressing produces only tiny amounts of juice — one reason for the extremely high prices of ice wines.
Who Makes Ice Wine
Germany and Austria were the traditional producers of ice wine (Eiswein in German), but in the last ten years Canada has taken over as the largest producer. Canadian winters are much more predictable. The Canadian versions use a variety of grapes besides Riesling, including some lesser known varieties such as Vidal, a French hybrid.
Canada, Germany, and Austria strictly regulate the making of ice wines. Among other things, there are standards for sugar levels and temperature at harvest. Ice wines produced in the United States — particularly in Washington State, in New York's Finger Lakes region, and in states near the Great Lakes such as Michigan and Ohio — are not bound by such strict standards.
Some maverick producers use an alternate method for making ice wine: They stick the grapes in the freezer before pressing them. The lower prices for these ice wines reflect the easier production.
Serving Ice Wine
Ice wines and sweet late harvest wines come in small (375 ml) bottles with big price tags. It isn't unusual to pay $60 to $200 for a half bottle. Fortunately, you serve less of them — two to three ounces — than you would a table wine. They're best served chilled and in proper stemware.