A glass of wine has about 150 calories as a general rule. If a bottle of wine had a proper ingredient list, rather than just the almost useless statement “contains sulfites,” then we’d all know what’s in a bottle, how it’s altered, how much is a proper serving and the caloric intake. This week, I’m going to fix that. Here’s what’s in your wine.

The main ingredients are water, alcohol and sugars. Water makes up well over 75 percent of wine. Alcohol is the next largest percentage and is noted on the bottle as the ABV, or alcohol by volume.

If you see “12 percent” on the label, then you know 12 percent of the wine in your glass is alcohol. In comparison, a beer might be 5 percent while a shot of vodka is 40 percent. Sugars make up a much smaller percentage than the alcohol, and often, these two are inversely correlated.

If you find a low-alcohol wine, 6 percent, it will taste sweeter than a wine that is 12 percent, which will taste drier. This is because during fermentation, the yeasts ate less sugar in the 6-percent wine, making it taste sweet and having less alcohol, which is the byproduct of yeast fermentation. You can’t have high-alcohol and sweet wine unless you add more of one or the other. To create fortified dessert wines, winemakers make them sweet and intoxicating.

Other ingredients are tiny and make up less than a single digit percentage. These are acids (tartaric, malic, lactic, citric, succinic, acetic), anthocyanin (water soluble pigments that make red wine red) and minerals. The various minerals are iron, nitrogen, phosphorus, magnesium, potassium, flouride, sulfur and calcium.

A standard bottle contains 750ml (milliliters), or if you prefer imperial measurements, 25.3 ounces of wine. A magnum is a double-sized bottle containing 1.5 liters. The bottle sizes grow all the way up to a Nebuchadnezzar, which is 15 liters, equivalent to 20 standard bottles. When you order a glass of wine at a restaurant, the server will bring 5 ounces, or 150ml of wine. Thus, a bottle of wine contains about five servings.

Figuring out the caloric intake of those 5 ounces, 150ml, is a bit more problematic. Not all wine is the same. You’d be forgiven if you thought that sweeter wine is more caloric than dry wine since a slice of chocolate cake is more caloric than a slice of pumpernickel, but it’s not the sugars that contain the calories - it’s the alcohol.

Alcohol has 7 calories per gram verses sugar which has 4 calories per gram. This makes high-alcohol wines such as California Zinfandel, or barbeque-friendly Argentinian Malbec, both at about 15 percent alcohol, much more caloric than a sweet German Riesling at 7 percent.

For your reference, here is the caloric value of a bottle of red or white wine:

- 10 percent ABV / 460 calories / 92 calories per glass

- 11.5 percent ABV / 600 calories / 120 calories per glass

- 12.5 to 13.5 percent ABV, 750 calories, 150 calories per glass

- 14 percent ABV / 820 calories / 164 calories per glass

- 21 percent ABV (fortified wines such as port) / 1,440 calories / 115 per 2-ounce glass

The good news is that a typical dry wine contains absolutely no fat and because of the very low amount of sugars, hardly any carbs. Not that I’m counting.

David Devere is teaching wine classes locally. Contact him at david@savvynomad.com or visit savvynomad.com for the schedule and register for a class.