Ice wine, also known as Eiswein in German, is a type of sweet dessert wine made from grapes that have naturally frozen on the vine. This winemaking process is unique and typically requires specific climatic conditions.
Here's an overview of how ice wine is produced:
Grape Selection: The key to making ice wine is to use grapes that are still on the vine and have naturally frozen. The grapes used are often varieties that can withstand cold temperatures without rotting, such as Riesling, Vidal Blanc, and Cabernet Franc.
Weather Conditions: The grapes need to experience a hard frost, with temperatures dropping below freezing (usually around -8 to -14 degrees Celsius or 18 to 7 degrees Fahrenheit). The grapes must freeze while still on the vine, concentrating the sugars and flavors.
Harvesting: Harvesting typically occurs in the early morning hours when the grapes are still frozen. The grapes are carefully picked and processed while they are still in a frozen state to maintain the concentrated sugars and flavors. Harvesting is often done quickly to prevent the grapes from thawing.
Pressing: The frozen grapes are immediately taken to the winery and pressed while still frozen. Because the water content is frozen, only the concentrated, sugary juice is extracted. This results in a small amount of highly concentrated, sweet juice.
Fermentation: The extracted juice is then fermented into wine. The high sugar content in the juice can make fermentation a slow process. The fermentation is typically stopped before all the sugar is converted into alcohol, leaving a sweet, high-acid wine with a lower alcohol content than many other wines.
Aging: Ice wine is often aged for a period of time to allow the flavors to develop and integrate. The wine is then bottled and ready for consumption.
The entire process is labor-intensive and dependent on specific weather conditions, making ice wine a relatively rare and expensive type of wine. Ice wines are known for their intense sweetness, rich flavors, and vibrant acidity, making them a popular choice for dessert or as a pairing with cheeses and certain desserts. Germany and Canada, particularly the Niagara region, are well-known for producing high-quality ice wines.