by Lisa Frederiksen

One of the most common reasons people find themselves inadvertently drinking more than they’d intended is the confusion that surrounds the idea of “A” (one) drink. The following is an excerpt from my upcoming book, New Thinking About Drinking: 7 Things You May Not Know. Before you continue reading, it is important to know that one standard drink is defined as: 5 ounces of table wine, 12 ounces of beer, 1.5 ounces of distilled spirits (e.g., vodka, whiskey), or 3.3 ounces of champagne.

Alcohol By Volume (ABV or ALC. BY VOL.) and “Proof” Explained

As you probably know, alcohol is one of the ingredients in beverages with names like beer, wine, tequila, Mike’s Hard Lemonade and champagne. Alcohol is the ingredient that gets you drunk (why and how is explained in Chapter 2.)  But alcohol is not something that grows on a tree or in the ground. It is something that is created by a process called fermentation.

The scientific term for alcohol is ethanol. To get ethanol (alcohol), people mix yeast (you may know of yeast because it is used in baking) and sugar – the kind of sugar that is naturally found in fruits and vegetables.

When mixed together over time, the yeast breaks down the sugar into ethanol and carbon dioxide. This process is called fermentation. As the fermentation process continues, the carbon dioxide gas bubbles out, and all that is left is the ethanol and water.

Different sugar sources make different kinds of alcohol. The sugar from crushed grapes, for example, is used to make wine. The sugars from grain, potatoes, beets and other plants are used to make vodka.

Alcoholic beverages like vodka, rum, gin and whisky go through another process called distilling. Distilling is the process that removes the water from the ethanol. This is why you hear of vodka, rum, gin, whisky and the like being called, “distilled spirits.”

So what are you supposed to do with this information?

If you look at a label on a bottle of wine, you will see – usually in very tiny letters – something like ABV 14% or ALC. BY VOL. 14%. This is saying that in that particular bottle, 14% of the liquid is alcohol. In other words, the alcohol by volume (ABV) is 14%.

Distilled spirits are labeled differently. If you look on a bottle of distilled spirits, you will see another number and word – also in very tiny letters – that will read “80- proof.” Proof is a number equal to twice the ABV. So in a bottle of 80-proof vodka, for example, the ABV (alcohol by volume) is 40%, which explains why you would get drunk on 10 ounces of vodka but maybe not get drunk on 10 ounces of wine. In other words, both are 10 ounces, but the vodka contains a lot more alcohol by volume than does the wine (40% vs 14%). This also explains why a 1.5 ounce shot of 80-proof vodka and 5 ounces of wine are both equal to “A” (one) drink. Though very different in size (1.5 ounces vs 5 ounces), each one contains the same amount of alcohol, therefore both are considered to be a standard drink.

Where’s the Standard Drink Label When You Need It?

After all that, the question still remains, “So how does ABV or proof tell a person how much alcohol is in “A” (one) drink?” Answer: It doesn’t.

This is where having a standard drink label that informs you of how many drinks are in a particular cocktail or in particular can or bottle would really help. Take a bottle of table wine, for example, a standard drink label would tell you that 5 ounces = one drink, and that in the bottle, there are five drinks. The label could be very simple. It could be something along the lines of: SD = 5 ounces; TOD = 5. [SD = standard drink; TOD = total number of drinks.]

Since there is no such thing as a standard drink label, the next best thing is to take a look at the following picture and realize that each glass contains “A,” drink; in other words, one standard drink.