How much water is in wine

The reason we love Vivino is because we love vino. But do we know what the wine we love is actually made of?

Wine is food, but there’s no ingredient list on the label. Grape juice is a given, but that’s not the whole story; wine is made of hundreds, if not thousands, of different molecules. Many of them are aroma molecules from the grapes themselves (primary aromas), the winemaking (secondary), and the aging (tertiary). Though they’re crucial for our enjoyment, aromas are only a very small proportion of a wine’s composition.

So what is wine really composed of?

85% Water

There’s a reason for the ancient tradition of drinking wine besides the pleasure of its alcohol content: wine is mainly water. Long ago, wine was safer than water because it was less prone to dangerous bacterial contamination. This was particularly true in warm regions where water was rarer could get spoiled more easily. This is perhaps why the story of wine started in warm and dry regions around Mesopotamia and around the Mediterranean Sea.

13(ish)% Alcohols

It’s no secret, wine contains alcohol; it’s produced when yeasts consume the sugar in grape juice, turning it into alcohol and carbon dioxide. The alcohol percentage (referred to as alcohol by volume or ABV) varies from wine to wine. Wines on the low end contain around 7%. These are often sweet wines whose fermentation stopped early, leaving unfermented sugar, including sparklers like Moscato or still wines like some German Rieslings.

Naturally fermented wines rarely go over 15% alcohol because yeasts run out of sugar to ferment. High alcohol wines (14% to 15%) are generally from warm regions where grapes reach a high level of ripeness with high concentrations of sugar. Only fortified wines have alcohol percentages of 17% to 20% or higher.

1% Glycerol

Chemically, glycerol is an alcohol, hence the ‘ol’ at the end of the word. It doesn’t have any effect on our nervous system, and our bodies treat it more like a sugar. Glycerol is a byproduct of fermentation, generated by the yeasts as they transform sugar into alcohol.

Glycerol is has an oily texture that brings viscosity to wine. It contributes to forming the legs (or tears) we see on a glass when we swirl a wine. Some winemaking yeasts are selected for synthesizing a lot of glycerol resulting in wines with an oily texture and slightly lower ABV, since what’s fermented into glycerol is not fermented into alcohol.

A cool fact: glycerol tastes rather sweet, which partially explains why some wines taste a bit sweet though they contain very little sugar.

0.5% Acids

Acidity in wine is measured in pH, usually between 3 and 4; it is often more acidic than orange juice, but less than most sodas. The main acid in wine is called tartaric acid. The grapevine in one of the very few plants to generate tartaric acid; as a result, most bacteria are unable to metabolize it. This is why wine is so resistant to spoilage.

Unlike the acids in many fruits, the concentration in tartaric acid doesn’t decrease much as grapes ripen, explaining while all wines are relatively acidic, even ones made from the ripest fruit. Grape juice also contains malic acid, whose concentration does decrease during ripening. This helps explain why wines made from riper grapes are less acidic than wines made with ‘greener’ berries.

Malic acid is quite tart and not very stable, which is why winemakers may choose to let it be converted into smoother acid lactic acid. Learn more about this process in What is Malolactic Fermentation? If you want to dive deep into this important wine component, check out Why is Acid so Important in Wine?

Carbohydrates (sugars)

Obviously, the concentration in sugar in wine can vary greatly depending how ‘sweet’ the wine is. Very dry wines have virtually no sugar at all, and some sweet ones can contain over 200 grams per liter. However, most wines, even dry ones, contain between 0 and 10 grams per liter (g/L) of carbohydrates.

Sugars in wine are mainly the natural fruit sugars: fructose and glucose, generally in equal proportions. However, wines can contain small but significant quantities (1 or 2 g/L) of unfermentable sugars. Like the name indicates, they cannot be fermented by yeasts or bacteria. They therefore remain in the wine as “residual sugars” and provide some sweetness.

0.1% Phenolics

Despite their relatively small proportion, phenolics are a big part of what make wine special. Phenolics called flavonoids and anthocyanins give white and red wines their distinctive colors. The tannins that provide wine’s drying astringency and some bitterness are also phenolics. Tannins are in much higher concentration in red wines, although whites contain small quantities, too. Learn more about how tannins are fundamental to wine in The Differences between Red and White Winemaking.

And that’s it! Lots of water and a few powerful molecules come together to make the amazing variety in every glass of wine you drink.

About the author Julien is the founder of Social Vignerons winner of the 2015 Best New Wine Blog from the Wine Blog Awards. Follow him on Vivino and on Twitter.

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