Alcohol in Wine: What It Does and How Winemakers Control It

Frank Renaldi, Head Winemaker • August 14, 2026

Alcohol in Wine

From the notebook of Frank Renaldi, Head Winemaker at Tranquillity Vineyard & Winery in Middlebury, CT.

Alcohol is a necessary part of red and white wine. Besides causing a "happy feeling," the alcohol is part of a balanced wine with structure and mouthfeel. Here is how it gets there, and how a winemaker keeps it in check.

It Starts With Sugar in the Grapes

As the grapes ripen, the sun and heat help the sugar in the grapes to increase. The more sugar in a grape, the higher the potential for alcohol.

How the Winemaker Measures and Manages It

The winemaker will measure the sugar in the grapes to determine how much alcohol will be created in the wine, as the yeast eats the sugar and converts it to alcohol and CO2.

The sugar level can be adjusted up by adding table sugar to the grapes, or it can be reduced by adding non-chlorinated water to dilute the sugar content.

Typical Alcohol Levels by Wine Type

Typical desired alcohol levels in white wine are 11 to 13 percent, and 13 to 15 percent in red wines. Fortified wine will range from 18 to 20 percent.

Explore Balance in the Glass in Middlebury, CT

Balance is what we aim for in every bottle at Tranquillity Vineyard & Winery. Join us on Lake Quassapaug in Middlebury, Connecticut for a tasting and see how alcohol, fruit, and structure come together in a handcrafted wine.

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