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.

Outdoor wedding ceremony on a green lawn with white chairs and a large circular monogram backdrop under blue sky
By Frank Renaldi, Head Winemaker August 14, 2026
What makes a wine a port? Head Winemaker Frank Renaldi of Tranquillity Vineyard in Middlebury, CT explains fortification, aging, and the styles of port.
Outdoor wedding ceremony with white chairs on a lawn, trees behind, and a round green Vermont Law School sign.
By Frank Renaldi, Head Winemaker August 14, 2026
What are wine tannins all about? Head Winemaker Frank Renaldi of Tranquillity Vineyard in Middlebury, CT explains where tannins come from and what they do.
Outdoor wedding ceremony setup with white chairs on a lawn, trees in the background, and a university logo overlay.
By Frank Renaldi, Head Winemaker August 14, 2026
Why do winemakers blend wines? Head Winemaker Frank Renaldi of Tranquillity Vineyard in Middlebury, CT shares how blending creates more complex wines.
By Tranquillity Vineyard & Winery August 7, 2026
Considering a vineyard wedding in Connecticut? See how weddings work at Tranquillity Vineyard in Middlebury, from timeline and capacity questions to booking.
By Tranquillity Vineyard & Winery August 7, 2026
Curious about the monthly book club at Tranquillity Vineyard in Middlebury, CT? Learn how to join, what to expect, and how to find each month's pick.
By Tranquillity Vineyard & Winery August 7, 2026
Planning a fall event in Connecticut? Learn how private events work at Tranquillity Vineyard on Lake Quassapaug, from spaces and timing to how booking works.
By Tranquillity Vineyard & Winery August 7, 2026
Planning a baby shower or sip and see in Connecticut? See how Tranquillity Vineyard in Middlebury hosts celebrations with lakeside views and handcrafted wine.
Outdoor wedding ceremony setup on a sunny lawn with white chairs and a green circular logo overlay.
By Tranquillity Vineyard & Winery July 8, 2026
Tranquillity Vineyard & Winery in Middlebury, CT holds a 4.9-star rating with 97% positive reviews. See what guests love most about their visit.