What are IBUs?

What are IBUs?


The world of craft beer has plenty of acronyms. And after ABV (alcohol by volume) the most commonly used one you’ve likely heard is IBU which stands for International Bitterness Units Scale. 

This scale indicates the level bitterness in a beer, often ranging from 5 (low bitterness) to 120 (high bitterness) but it can technically goes as high as 1000 or even beyond. (note from Ty, a beer with 1000 sounds like my nightmare.)


Great, we can use a beer’s IBUs to know how bitter it will be…right? 

Nope, not quite.

A beer’s IBU number only tells you how much bitterness is present in a beer and doesn’t account for other tastes (like sweetness) which may suppress and/or balance the bitterness you perceive. 


For example, two beers with identical IBUs won’t be perceived as equally bitter if one features lots of sugars (sweetness) in its recipe. Technically, a beer with an IBU of 60 and lots of sugars (sweetness) in the recipe could be perceived as less bitter than a beer with an IBU of 30 and no sugars.


I like to think of IBUs as the amount of icecubes in a glass of water. Imagine a glass of water with 10 ice cubes…. sounds like it would be cold right? Well, what if you pour in boiling water? Not so much. So the IBUs/icecubes are only half the equation.

In addition to the balancing effect that residual sweetness has on perceived beer bitterness, there are other factors and flavours that we perceive as bitter. Trained beer analysts and judges, our experienced servers, and people with inherently sensitive palates can differentiate between hop-bitterness (iso-alpha acids), hop-bite (oxidized hop oils), astringency (strong black tea ie. tannins) and acetaldehyde (fermentation byproduct, unripe fruit/green-apple), but the casual consumer would describe all the above as “bitter.” Likewise, IBUs by definition are strictly a measurement of iso-alpha acid content, and do not consider these other three significant contributors of “bitter.”


This is all compounded by the degrees of sensitivity everyone has for tasting these substances. I personally have the sweetest of tooth and would most likely describe something as bitter before most people.


So if IBU doesn’t tell us what to expect in terms of bitterness, how do we explain a beer’s bitterness? 


Many craft beer drinkers use the term “perceived bitterness” as a qualitative parameter of a beer’s character. It means just that, how bitter you perceive the beer. The Cicerone® Certification Program use a scale of “perceived bitterness” ranging from “low”, to “moderate”, to “pronounced”, to “assertive”, and finally “highly assertive” for the beers which are perceived as very bitter.


TL:DR Because IBUs don’t tell the whole story, they set false expectations and as such, we don’t mention them anywhere. We hope you learned something about IBUs  


Oh, before you go, here are some other acronyms you’ve likely heard related to beer.

SRM – Standard Reference Method – The colour of a beer.

BJCP – Beer Judge Certification Program – A non-profit organization formed to promote beer literacy and the appreciation of real beer, and to recognize beer tasting and evaluation skills.  

ISA – India Session Ale – A style of beer. The “session” means you can enjoy many of them without overloading your palette or liver.

IPA – India Pale Ale – A style of beer. Also lookout for the DIPA which stands for DOUBLE IPA. 

APA – American Pale Ale  – A style of beer.

FTU – Formazin Turbidity Units – How hazy a beer is. This acronym isn’t common in everyday speech; most people just say “hazy” or “kinda hazy” or “not hazy”.

OG – Original Gravity – Okay this one is actually pretty complicated and has to deal with the brewing process and not just “beer”. We’ll spare you the technical explanation for now but if you’re curious about brewing, ask your favourite brewer about gravity next time you see them.




Ty Johnstonmonth, learn