Wines produced in Canada—the largest region making ice wine—must adhere to the Vintner’s Quality Alliance, which sets strict guidelines for ice wine production. To achieve the ice wine designation, the grapes must not thaw, and they cannot be artificially frozen. (Several wineries produce ice-wine-like products with artificially frozen grapes using a process called cryo-extraction, but the results cannot technically be called ice wines.) The difference? “It’s not as intense,” Tresner says. “I’ve had some that are pretty good, but they don’t quite have the intensity and balance of a true ice wine.”
With legitimate, naturally frozen ice wines, the process and the cost are quite intensive. This is part of the reason why ice wine is typically sold in half-size bottles. Since the frozen grapes are harvested later than other grapes, nets are used to cover them and afford protection from pests and animals. Once picked, the grapes are pressed immediately, while still frozen; and the skins and frozen water crystals are carefully extracted from the juice. The fermentation process takes four to five months and requires about three times as many grapes to produce one half-size bottle of ice wine as it does one traditional bottle of wine.
The result of all the expense and labor is a sweet, nectarlike juice that’s not quite a liqueur and not quite a port. Medium to full bodied, ice wine is most often made from riesling, cabernet franc, vidal gewürztraminer or pinot blanc grapes, though winemakers are now experimenting with other varietals and even sparkling ice wine.