Some folks may think that making ice wine requires the use of a lot of ice, but this is only partially accurate. To make this typically sweet dessert wine requires a hardy breed of white grapes such as Riesling or Vidal that can withstand longer times on the vine. Typically, the grapes are left on the vine until the first frost and are harvested by hand early in the morning while the grapes are still frozen, making them ideal for making ice wine.
The grapes remain frozen until they are crushed and instead of juice, the squeezing are ice crystals high in sugar with a good level of natural acid. Typical wine grapes will have a sugar content reading of between 20 and 22 brix, but when making ice wine the sugar level will be about 35 brix. This unit of measurement indicates the amount of sucrose in the liquid from the grapes. A reading of 35 indicates a sucrose content of 35 grams and 65 grams of liquid.
Due to the high sugar content when making ice wine the fermentation process is usually longer, three months or more, resulting in higher production costs for this wine. It also results in a very sweet wine and typically not made with high acid, low sugar grapes. Typically, white grapes are used, but red wild wine and some of the European wine grapes are utilized for making ice wine.
Basic Processes Remain The Same
When making ice wine, once the grapes have been crushed, the process of making wine remains very similar to the traditional wine making method. One the grapes have been crushed, the acid and sugar content is tested and adjusted as needed. However, knowing the sucrose content of the frozen grapes is going to be higher to begin with, it is rare that it will be diluted.
Due to the process of making ice wine, very few people have attempted to make it at home. The temperature controls and equipment needed to crush frozen grapes is different that crushing other grapes. Additionally, not many home winemakers are going to want to hit the vines at daybreak on a frozen day to pick their grapes and crush them the same day.
This beverage was, as many good things, was discovered by accident, following an early freeze in Germany. Vineyard owners had to decide whether to try to make wine from the frozen grapes or simply throw them away. After the first year of trying making ice wine has turned in a business from those first few bottles produced as an experiment.
