In relation to beers, IBU is an abbreviation for “International Bitterness Unit(s).”
One can use IBU as an off-hand indicator of the beer’s bitterness. The bitterness is measured as low to high. In other words, generally, the higher the IBU number, the more bitter the beer.
Scientifically and technically speaking, IBU quantifies the amount of isohumulone from the hops utilized in the beer. As far as this post is concerned, the only thing you need to know about isohumulone is that it’s pretty much the name of the compound that bestows us with that incredible bitter flavor.
It’s Not All About the IBU Though
In the entire beer-producing process, IBU and hops are only part of the equation. A lot more goes into creating a beer profile and the final product.
Translated, you may run into a scenario where a beer may have a high IBU but may still not taste that bitter or as per the expectation. One of the primary reasons for is that aspects such as the malt and grain can often counter the bitter taste. Not to mention, our tongues can sense a variety of subtle palates that beers offer.
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Let’s Not Forget About “Perceived Bitterness”
As alluded to, IBU is just one side of things — from the many. The perceived bitterness is a concept that tells us how much bitterness we actually feel & taste.
A great example I read online is about Black Coffee. By itself, it is bitter. However, when you add sugar, it masks the original bitterness. So when you drink coffee with sugar, the bitterness you feel would be less than it would have been as a standalone item.
A similar philosophy applies to beers too. Even if a beer may have a peak amount of IBU — which will always be there- other elements, such as malt/grain, etc., commonly hide or take away its intensity.
Other Things To Know About IBUs

The most traditionally recognized IBU range is from 0-120 onwards. However, you’ll find that in practice, very few beers reach an IBU of around 100. Most beer judges consider 120 the upper limit, and it seems very hard for the human tongue to sense any more bitterness after that point.
This has been kind of asked and answered. Nonetheless, to get a sense of where 75 may stand, consider that the Blue Moon Belgian White Beer has an IBU of 9.
For context, according to the Beer & Brewing website, IPAs can have 55-70 IBUs, Amber lagers may contain 20-25 IBUs, and American Pale Ales can account for 30-35 IBUs.
In summary, remember that IBU is very literal. The reality of the bitterness in beers is dependent on a variety of factors. Still, it’s an acceptable method to scope out what to expect in a beer, taste-wise.
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