If the vine is frozen, the wine will be bad, right? Well, not always. Some winemakers actually let the grapes freeze during the winter to produce a delicious dessert wine, rightfully called icewine (Eiswein in German).
Making icewine is a very risky process: the grapes must be harvested at the right temperature so that the water can freeze whilst they are still on the vine, which reveals a much more concentrated and sweet taste. This means that if the frost comes too late, the grapes can rot and therefore the harvest will be completely lost. Unlike other dessert wine grapes, this process doesn’t need the grape to be affected by noble rot (Botrytis cinerea), a disease which removes the water from the grapes and reveals a sweeter wine, as the water is naturally removed by frost. However, it doesn’t prevent the grapes to contract the disease. Unaffected grapes are then more praised and called ‘clean’.
The harvest is also very difficult to organize as you need a lot of labour force as soon as it is cold enough and it all has to be done very quickly to avoid the sunlight warming the grapes. As you can imagine, icewine is more expensive and produced in smaller quantities than other dessert wines due to this difficult process. The biggest producers are Germany and Canada thanks to their perfect weather conditions.