The word “IBU in beer” is something that you’ll often see listed on a beer label. While it might sound like some kind of strange language, it stands for International Bitterness Units — and it indicates how much bitterness there is in that particular beer.
International Bitterness Units (IBU) is a measure of the bitterness of beer, and all beers will have either a high or low IBU reading; it depends on how many hops were used to brew that beer. The higher the IBU reading, the more bitter the beer will be.
But what does that mean? And why is it important to know when drinking beer?
What Is the International Bitterness Unit?
The International Bitterness Unit is a unit of measurement that is used to gauge the amount of bitterness in beer. It’s a common misconception that IBUs refer to the amount of hops in beer, but that’s not the case.
Instead, IBU refers to the amount of iso-alpha acids (parts per million of isohumulone) from hops in beer, which is what gives beer its bitter flavor. To measure how bitter a beer is, scientists use a lab-based test that determines the parts per million of isohumulone in the beer.
From there, they can calculate the IBUs, which allows them to determine how bitter the beer will taste. The scale ranges from 0 to infinity since there is no ceiling on the IBU scale because you could make a beer more bitter by adding more hops. However, when beer exceeds 120 IBU, the tongue can not taste any more bitterness.
What Causes Beer to Taste Bitter?
Bitter flavors in beer are caused by compounds called iso-alpha acids. These compounds are naturally present in hops — which are a key ingredient in beer.
When you add bittering hops during the brewing process, those compounds become dissolved into the liquid, which is why they’re called “iso-alpha acids.” The hop varietals used, the age of the hops, and the length of time boiled determine the bitterness level of your brew.
When you taste a beer, the iso-alpha acids act as a trigger, activating your brain’s bitterness sensors. Once those sensors have been activated, they stay on high alert for more bitterness.
This is why you might notice that a high-IBU beer becomes almost too bitter as you drink more of it — because the bitterness sensors are being continually triggered.
The malt and other flavors can mask the actual taste of bitterness in beer. You should note that a less malty beer with a low IBU such as 20 may taste more bitter as compared to a more malty beer with an IBU of 50.
How to Measure IBUs in Beer
IBUs can be measured using a specialized lab test, which is what many breweries will do before adding a beer to their label. Alternatively, there are a few at-home methods for measuring the IBUs in beer.
One of the most common at-home methods is the Rapid IBU Test, which involves adding a few drops of beer to a small vial. Once the beer has been added to the vial, you add a few drops of reagent.
This reagent causes a chemical reaction that produces a color change, which allows you to determine the level of bitterness in the beer.
Another option is the beer wheel, which allows you to calculate the IBUs based on the amount of malt, hops, and water that was added to the beer. The IBU scale offers a general guideline for the taste of your beer.
However, IBU may not be a reflection of the true bitterness level in your beer since it does not factor in the slew of herbs and spices used in the beer. Moreover, the taste can be masked by the malt flavor.
The Importance of IBU in Beer
The level of IBUs in a beer is an important indicator of its flavor and intensity. While many people think that adding more hops will automatically make beer more bitter, that’s not the case.
The amount of alpha acids in hops varies, which is why adding more hops to beer doesn’t always make it more bitter. Because of this, it’s important to measure how much bitterness a certain hop will add to a beer.
This is why breweries test the IBUs in their beer — to make sure that they have the amount of bitterness that they want in each beer.
However, the perceived bitterness will vary from beer to beer. Even though there is a correlation between the tasted bitterness and the actual IBU, the perception matters in an individual’s taste.
Different Beer IBUs
| Beer | IBU |
| Light Lager | 4-10 |
| Blond Ale | 14-25 |
| Saison | 20-38 |
| Pilsner | 25-45 |
| Dry Stout | 30-35 |
| Pale Ale | 30-50 |
| Hazy IPA | 30-50 |
| Hazy Double IPA | 45-80 |
| West Coast IPA | 50-70 |
| Imperial Stout | 50-80 |
| Double IPA | 65-100 |
Craft beers may have a different IBU from the classes above since the brewer may determine the level of bitterness they want in their beer. However, in general, the above is the classification of different types of beers with their IBUs.
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High IBU Beers
High IBU beers are the beers that are known for being exceptionally bitter. This is usually because the brewery has added lots of hops to the beer, which has boosted the level of IBUs.
High IBU beers are usually meant for people who like the taste of bitterness. They might not be the best choice for someone who isn’t a fan of bitterness — as they’ll likely find them too harsh.
Some examples of high IBU beers include American IPAs, American Pale Ales, Imperial IPAs, and Imperial Pale Ales.
High-IBU beers are balanced beers that have a lot of flavor. They are great for those who love darker beer types, like stouts and porters.
- Stout: This dark beer has an IBU level of 50–80.
- Porter: This dark beer has an IBU level of 30–60.
- India Pale Ale (IPA): This bold beer has an IBU level of 40–90.
- American Pale Ale: This hop-forward beer has an IBU level of 40–100.
- Imperial IPA: This strong beer has an IBU level of 70–100.
Low IBU Beers
Low IBU beers are the beers that are known for being less bitter than the average beer. This isn’t to say that they are completely flavorless, but just that they are more balanced and less bitter than other beers.
Low IBU beers are usually great for anyone who isn’t a big fan of bitterness. Some examples of low IBU beers include Light Lager, German Pilsners, Bohemian Pilsners, and English mild ales.
These are lighter beers that don’t have a lot of flavors. They’re great for those who don’t like beer with a lot of taste. Low IBU beers are often served with food, as they don’t have a bold flavor that might overpower the food being served.
- Lager: This light beer has an IBU level of 5–15.
- Wheat Beer: This light beer has an IBU level of 5–15.
- Cream Ale: This light beer has an IBU level of 10–15.
- Pilsner: This light beer has an IBU level of 25–45.
- Belgian Tripel: This light beer has an IBU level of 35–45.
- Belgian Witbier: This light beer has an IBU level of 15–25.
- German Altbier: This malty beer has an IBU level of 20–35.
Finding Your Favorite Beers by IBUs
If you’re looking for a new beer to try, you can use the IBUs as a guide. For example, if you usually drink mild ales that are low in IBUs, you can use the higher IBUs of IPAs to find a new beer that’s similar in taste and bitterness.
If you’re not sure which type of beer you’d like to try, you can also use the IBUs to find a beer that’s somewhere in the middle.
For example, if you normally drink lagers that are low in IBUs, you can look for an IPA that sits somewhere in the middle. This way, you’re still drinking a beer that you enjoy and know, but with a slightly higher level of bitterness.
IBUs and AAUs: How Are They Different?
While IBUs and AAUs are both used to gauge the amount of bitterness in beer, they are calculated in different ways.
Hop bitterness is measured in two ways: International Bittering Units (IBUs) and Alpha-Acid Units (AAUs). While both measurements are used to measure the amount of bitterness in beer, AAUs are used for hops that are added for flavor.
IBUs measure the amount of hop bitterness added to the beer at the end of the boil. AAUs measure the amount of hop bitterness added to beer throughout the entire brewing process.
AAU measurements are more accurate because they take into account factors like the age of the hops and the way the hops are processed. The measurement for AAUs is determined by lab analysis.
The AAU is the total amount of alpha acids when you add the hops at the beginning of the brewing process, while the IBU is the level of bitterness at the end.
This is why the AAU is usually significantly higher than the IBU — because the majority of the alpha acids have been used up by the time the beer has been brewed.
IBU vs ABV in beer
One important thing to note is that the level of bitterness in beer is not the same as the level of alcohol in beer. Bitterness and alcohol content are two completely different things. The International Bittering Units are often confused with the alcohol content in beer.
However, they are different measurements. A higher IBU level doesn’t always mean that the beer has a higher ABV level.
While it’s possible for high-IBU beers to have low ABV, it’s also possible for low-IBU beers to have high ABV.
This is because the amount of bitterness in a beer is determined by the amount of hops added, while the level of alcohol is determined by the amount of yeast added during the brewing process.
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Final words
Overall, the International Bitterness Unit is an important part of the beer-drinking experience. After all, it’s impossible to taste the bitterness of a beer if there’s no bitterness in that beer.
The higher the IBU level, the more bitter the beer, and the lower the IBU level, the less bitter the beer. The IBU level can help you pinpoint the flavor of a beer and can also tell you how strong the beer is.
Finding a beer that suits your taste can be difficult if you don’t know what you’re looking for. The best way to go about this is to find a list of beers and their IBU levels. You can then use this information to select the type that best suits your taste.
