A well-known, yet little understood way of measuring how bitter a beer is, IBUs are often thrown around as a trendy stat on product labels and beer descriptions. While they’re a very relevant way of measuring certain aspects of a beer’s flavor and aroma, they do not (in any way) make a beer better or worse. It’s all about matching your preferences to the measurable facts about a beer to find that perfect sweet spot for you.
I.B.U. = International Bittering Unit
IBUs were invented because it was hard to measure how “bitter” a beer was, just like it’s hard to measure how “comfortable” your favorite sweater is…it was all about the perception. Since the early 20th century, the IBU scale was introduced (and has evolved) as a way to put a number to, or quantify, this perception and assess just how bitter a beer turned out to be when it was ready to drink.
The strict definition is simple: International Bitterness Units are a chemical measurement of the number of bittering compounds, specifically isomerized and oxidized alpha acids, polyphenols, and a few other select bittering chemicals, that make your beer taste bitter. The IBU correlates well, in most cases, with the sensory bitterness of beer, and this is why brewers use it. Almost all the beer you’ll ever drink will have a measured IBU between five (which is a very low measured bitterness) up to 120 (which is a very high measured bitterness). Most beer falls in a narrower range within these parameters (between 15-80ish), but that’s the gist of it
We want to be clear on something though. Beer is about the balance of ingredients and taste. Just because a beer has a higher IBU doesn’t necessarily mean it is perceived (or tastes) to be as bitter as something with a lower IBU. You can drink a strong Amber ale rated to 60 IBU that doesn’t taste nearly as bitter as a 55 IBU Pale Ale. The stronger malt flavor of the Amber ale matches the IBU’s of the beer and balances them accordingly. The IBU scale simply measures the amount of the chemicals in a beer that make it taste bitter. Make sense?
