Known as Eiswein in German, the high-quality dessert wine requires grapes to freeze on the vine.
Perfect conditions this year convinced vineyards to take a gamble on ice wine by leaving more grapes than usual hanging on the vine, Ernst Büscher from the German Wine Institute in Mainz said this week.
“That's perfect, because it ensures acidity levels are well concentrated,” he said, explaining this should lead to a crisp vintage without sickly sweetness.
Ice wine requires the grapes to freeze at temperatures below -7 degrees Celsius before being harvested and processed. The cold makes a particularly sweet beverage.
Using the so-called Oechsle scale to determine the density of grape must, German vintners recorded levels from 150 to 200 degrees. The higher the rating, the riper and more sugar content must has.
Whereas the Korrell vineyard along the Nahe River harvested an ice wine with 190 degrees Oechsle, the vineyard Balthasar Ress in the Rhinegau region brought in a Riesling ice wine reaching 170 degrees.
Büscher said the ice wine harvest could continue well into this week, with meteorologists forecasting double-digit minus temperatures for much of Germany.