Is there glycerol in wine?

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Dear Dr. Vinny,
Is there glycerin in wine?
—Timothy, Atlanta
Dear Timothy,
Glycerol (also known as glycerin and glycerine) is a non-toxic byproduct of fermentation, and a trace amount is present in most wines. Glycerin is a viscous, colorless and odorless liquid and gives wine a fuller, more pleasant texture. There’s also a slight sweetness to glycerin, which is considered a positive, as it’s able to help smooth a wine’s harshness.
The type of wine grape, how ripe it is and what kind of yeast it's fermented with can all impact how much glycerol a wine has. Temperature and nitrogen levels can also have an effect. Glycerol is also available to home winemakers as an additive to increase viscosity and sweetness. According to the TTB, however, it is not legal to add additional glycerol to commercial wine.
Other alcohol products might allow limited amounts of added glycerol, and it’s used as a sweetener in dairy products, sweets, jams and energy bars. It can also be added as a food thickener, or to keep food moist.
—Dr. Vinny