The brewing and craft beer industry use a lot of acronyms. Things like ABV (alcohol by volume), SRM (Standard Reference Method), and OG (Original Gravity), can all make it difficult to understand what a beer is like. One of these acronyms is called IBU.
The letters IBU stand for International Bitterness Units. These basically tell you how bitter your beer is.

We’ll cover more about what IBU is in this article, including how beer becomes bitter, and why IBU is so important when drinking craft beer.
Interested in learning more about IBU? Keep reading!
IBU Basics
IBU refers to the International Bitterness Scale. This scale is referred to when describing how bitter a beer is.
Brewers use the IBU metrics to balance the flavors in their beer, as well as tell buyers how bitter their brew is.
Everyone has different preferences, so if some people find a beer particularly bitter, others may find it doesn’t taste that bitter at all.
However, in most cases, the lower the amount of IBUs, the less bitter the beer will taste. The greater the IBU, the more bitter the taste.
Strictly speaking, IBU is a chemical measurement that details how many bitter compounds are within a beer. These include oxidized alpha acids, isomerized alpha acids, and polyphenols.
These composites are what give beer its bitter flavor.
Beer brands will vary in terms of IBU. Some prefer to advertise their greater IBU levels, but others like to brew beers with lower IBUs that appeal to less experienced beer drinkers.
Some kinds of craft beers, like American IPAs, are popular due to their greater IBUs, but others, like porters, have lower IBU levels.
The IBU Scale
Brewers use the International Bittering Units scale to judge how bitter a certain type of beer is.
This scale is used for all kinds of beer and is recognized internationally, which is why it’s a good reference point to estimate beer bitterness.
Some breweries use particular equipment to chemically quantify how bitter a beer is, but other brands simply estimate this.
Remember that the human palate shouldn’t be relied upon to judge IBU, so take these levels as a rough guide instead of an actual assessment.
The IBU scale starts at 0 and reaches above 120. There’s no end limit, but it becomes harder to judge bitter beers that are over 120 IBUs.
Most beers have IBU levels from 10-80. Any that are over 60 on the scale are thought of as particularly bitter.
Brewers rely on IBU levels to make sure that their batches are consistent. They can also use the numbers to balance out flavors within their brew.
For instance, a high IBU measurement counterbalance brews with a lot of malt sweetness.
Why Does Beer Taste Bitter?

One of the main ingredients in beer is called hops. Hops are full of bitter compounds known as alpha acids. These start to break down during the boil stage of the brewing process.
The boiling wort’s heat makes the alpha acids disintegrate, a process called isomerization. This creates iso-acids that taste bitter. The IBU scale measures the amount of iso-acids in a beer.
This doesn’t mean that all beers that contain hops are bitter. If hops are added later during the fermentation or boil process, they can deliver a noticeable hop scent and taste without the extra bitterness.
All hops are full of alpha acids which can taste bitter, but the amount of these can vary between different hops. Some brewers are selective about the hops they choose, as they try to impart particular flavors, scents, and bitterness levels.
Why Is IBU Important When Drinking Craft Beer?
Everyone has different taste preferences, so if you aren’t a fan of bitter flavors, you might believe that you should avoid beers with more IBUs. This isn’t true!
It’s important to think about how the bitter notes will taste in combination with all of the other flavors and aromas within a particular beer.
The IBU level will generally indicate how bitter a beer may taste, but other factors can affect this, like the kind of hops or malt that were used in the brew.
Bitterness needs to be thought about while considering a beer’s other ingredients. The different notes and scents are part of the experience when drinking beer, which is why some bottles with the same IBU level may taste more or less bitter than each other.
The right IBU level that describes a certain bitterness level will also vary with each kind of beer. For instance, if you order a pale ale and a stout with the same IBU level, the maltier stout will seem less bitter than the lighter ale.
The bitterness of a beer depends heavily on the other notes within a beer.
Types Of Beers With Higher IBUs
Now that you understand more about what IBU is, we’ll list a few examples with high IBU levels so you can try them out.
American India Pale Ale (IPA)
IPAs are the potent, bitter version of the American Pale Ale. These are usually higher IBU beers. American IPAs usually have an IBU rating of 50-70, which translates to a medium-high to high bitterness rating.
Double IPA
Double IPAs are a stronger version of the classic IPA. These usually have an IBU rating between 60-120, and taste particularly hoppy.
Imperial Stout
These beers are usually higher in IBUs, with most of them ranging between 50-80 on the IBU scale. The stouts are often brewed with dark malts, giving them a sweetness to harmonize with the bitter IBU levels.
The Bottom Line
IBU refers to the International Bittering Units scale which indicates how bitter a beer is. These won’t tell you exactly how bitter your beverage is, but it’s a good reference point to think about when deciding on a particular beer.
The IBU scale ranges from 0 to over 120, though most beers lie between 10-80. Other factors can affect how bitter a beer may taste, like the malt or hops that were used to brew the beer.
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