Winemakers decide when to pick grapes for ice wine based on a combination of factors such as sugar levels, acidity, and weather conditions.
Sugar Levels
One of the most important factors in determining when to harvest grapes for ice wine is sugar levels. Ice wine is made from grapes that have been frozen on the vine, which concentrates the sugars in the fruit. Winemakers typically wait until the grapes have reached a certain level of sugar content before harvesting them for ice wine production. This sugar content is measured in terms of Brix, which is a scale that indicates the sugar level in the grapes.
Acidity
Another important factor that winemakers consider when deciding when to pick grapes for ice wine is acidity. High acidity levels are essential for balancing out the sweetness in ice wine and giving it a crisp, refreshing finish. Winemakers will monitor the acidity levels in the grapes leading up to harvest and make sure they are at the optimal level before picking the grapes for ice wine production.
Weather Conditions
Weather conditions also play a crucial role in determining when grapes are picked for ice wine. Grapes used to make ice wine must be frozen on the vine, so winemakers need to wait for the right weather conditions to occur before harvesting the grapes. Typically, grapes are harvested for ice wine production in the early morning hours when temperatures are below freezing. This ensures that the grapes are frozen solid and will yield the concentrated flavors desired for ice wine.
Monitoring the Grapes
Winemakers will monitor the grapes closely in the weeks leading up to harvest to ensure they are at the optimal ripeness for ice wine production. This involves regularly testing the sugar levels, acidity, and overall flavor profile of the grapes to determine when they are ready to be picked.
Harvesting Process
The harvesting process for ice wine is labor-intensive and requires precision to ensure the grapes are picked at the right moment. Winemakers typically hand-harvest the grapes to ensure they are not damaged during the picking process. The grapes are then pressed while still frozen to extract the concentrated juice needed for ice wine production.