What Is ABV And How Is It Measured?

I don’t care who you are or what you “look” at when you pick a beer. I know for a fact that you’re paying attention to the ABV. I know this FOR A FACT.

Everybody cares about alcohol by volume (ABV) to some extent. If I’m trying to relax in the afternoon, odds are I’m not going to be slamming half a bottle of 13% ABV barley wine. I might not even go for a 6% ABV IPA (total lie, I can drink an IPA any day of the week).

So, back on track – how is ABV measured in beer? Let’s learn!

The Nitty Gritty of Measuring ABV

Alcohol by volume is, by definition, measured by taking “the number of milliliters (mL) of pure ethanol present in 100 mL of solution at 20 degrees Celsius (68 Fahrenheit),” per Wikipedia.

Let’s translate that into English:

ABV represents the amount of ethanol (alcohol) in a set amount of liquid. It more or less tells you what percentage of the drink is alcoholic.

Based on the stuffy definition, let’s get something clear: ABV changes. Depending on the temperature, the alcohol by volume of your beer could change – sure, it’s such a small amount that it’s probably negligible, but it still changes.

Other than that, nothing too special about measuring ABV in beer. Your local brewer makes the beer, bottles it, slaps a number on the label and tell you you’re drinking a 5.8% stout. Cool.

And never in a million years will that 5.8% change. After a beer is bottled, it’s locked in a suspended state, unaffected by the outside world…unaffected by time.

Not really, though. Guess what? The label that tells you the ABV is probably wrong, and governing bodies around the world know it.

If you didn’t want to waste your time reading that link, I’ll break down the interesting part: the US government accepts that a malt beverage (i.e. beer) can be within 0.3% off from what’s labeled. The EU is even more tolerant, letting alcohol be within 0.5% of what’s labeled.

Your beers are alive, and time makes them ferment. The time between when ABV is measured and when you drink it can be a while, and things can happen during that period. More specifically, the alcoholic content of your beer, wine, etcetera can grow over time.

Also, the brewer measuring the ABV of a beer might not know how to measure ABV properly. Fortunately, you can measure it yourself! But that’s for another post.

Is ABV Measured Differently in Liquor, Wine, and Beer?

Based on the definition, ABV is measured the same regardless of what the drink is. Different alcohol classifications are essentially for the consumer (and the government, if they choose to tax/regulate specific alcohols).

Because these drinks have different measurements, i.e. beer around 6% and whiskey around 40%, standard pours generally equate to the same amount of alcohol.

So, the difference between a full IPA and a shot of tequila is likely minimal…depending on how fast you drink them.

ABV vs Proof: What’s the Difference?

Ok, so you know what ABV is. Why does liquor say proof? Why doesn’t beer say proof? What is proof?

The term “proof” dates back to ole timey England where liquor was taxed based on strength. Of course, nobody knew how to measure strength, so they would just have to determine if it was strong with “proof.” Eventually, the term “100 proof,” i.e. is definitely strong alcohol, was measured using a super complex gravity system that set proof at about 57% ABV.

Fortunately for people living in the modern world, proof has since been simplified to equal double ABV, near enough the previous definition of proof. So, a 40% ABV liquor would be 80 proof. Aside from that, people say proof instead of ABV because it sounds cool.

ABV vs IBU: What’s the Difference?

More questions, huh? Ok, you’re in a local brewery and you see numbers on the board labeled ABV, IBU, and $. Hopefully you now know what ABV is and with any luck you already knew what $ was.

That other term, IBUs, stands for International Bittering Units scale. These numbers essentially tell you how bitter a beer is. Of course, this is super useful when you’re trying something new and you hate (or love) bitterness. As a general rule of thumb, the lower IBU number, the less bitter the beer.

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