What The Heck Is IBU In Beer?
IBU, ABV, SRM…it’s like beer abbreviation bingo over here. Today we’re talking about the first one, which stands for International Bitterness Units. While taste is often subjective, there is a standard for measuring how “bitter” a beer is. All beer is bitter to some extent (the Brits even call certain styles “bitters”), but there is one style for which this measurement is particularly important: the India Pale Ale. But is IBU in beer the only way to judge taste? Right this way, we’re about to get snooty about hops.
What Is IBU in Beer?
To recap: IBU in beer is a scale that measures the bitterness of a beer. More specifically, it measures the bitter compounds from the hops present in the brew. The higher the IBU number, the more bitter the beer might taste (emphasis on the might. There’s more to the story than just numbers-stay tuned).
How Is IBU Measured?
IBU in beer is measured in parts per million of iso-alpha acids using a spectrophotometer. This helps brewers calculate bitterness with precision. The scale typically ranges from 0 to 120. But just because the IBU is high doesn’t necessarily mean it will be more bitter than a lower IBU. The other ingredients in the beer can alter how bitter the taste is on the tongue. There’s a lot that goes into brewing the perfect beer. We know because all our beers are perfect. They read high on the International Perfection Units scaleTM .
What Causes a Higher IBU In Beer vs a Lower IBU?
The IBU (International Bitterness Units) level in beer is primarily influenced by hops, but it’s not just about how many hops you throw in. Several factors affect how your beer tastes and how that bitterness is measured.
Hop Variety
Different hop strains contain different levels of alpha acids, which are the bittering components extracted during the boil. High-alpha hops are often used to drive up IBU efficiently and typically contain between 12-18 percent alpha acids, though some varieties exceed this. Low-alpha hops (5 percent or less) contribute more to aroma and flavor with minimal bitterness. Beers brewed with high-alpha hops typically have higher IBUs than those made with delicate, low-alpha varieties.
A few common high-alpha hops strains include:
- Magnum (Germany/US) – 12–16% AA
Clean, neutral bitterness. Very popular for lagers and IPAs. - Warrior (US) – 14–18% AA
Smooth, clean bitterness with mild citrus and pine if used later. - Columbus / CTZ (US) – 14–17% AA
Spicy, pungent, earthy, with some dank qualities. - Chinook (US) – 12–14% AA
Piney and spicy with grapefruit notes. Good for both bittering and flavor. - Target (UK) – 10–13% AA
Earthy, floral, and sage-like. Often used in British ales.
Quantity of Hops Affects IBU In Beer
The more hops you use, especially early in the boil, the more alpha acids are isomerized (chemically transformed to become soluble in wort), resulting in more bitterness. A single IPA might use multiple pounds of hops per barrel, significantly increasing its IBU. Meanwhile, lagers and wheat beers use far less.
Timing of Hop Additions
When hops are added during the brewing process, it makes a huge difference:
- Again, early boil additions maximize the isomerization of alpha acids, contributing to more bitterness.
- Late boil additions preserve volatile oils that enhance aroma and flavor, but add little to no bitterness.
- Dry hopping (post-boil, during fermentation) adds aroma and complexity, but doesn’t increase IBU.
That means two beers brewed with the same hops can have vastly different IBUs depending on when the hops were added.
Boil Time
Longer boil times allow more alpha acids to convert into their bitter form. So, 60-minute boils generally extract more bitterness than 30-minute boils. Some double IPAs are boiled for 90 minutes or longer to get maximum IBU potential.
Does a Higher IBU In Beer Always Mean a More Bitter Taste?
Not necessarily. While IBU quantifies the chemical concentration of bitter compounds in a beer, it doesn’t tell the whole story. Taste, after all, is subjective. Additional ingredients and brewing techniques won’t change the technical IBU, but they can alter the perceived bitterness.
Several factors affect how bitter a beer tastes, regardless of its IBU:
1. Malt Sweetness & Body
- Sweetness from unfermented sugars or crystal malts can balance out bitterness.
- A malty beer (e.g. a barleywine at 60 IBU) might taste less bitter than a lean, dry pale ale at 40 IBU.
2. Alcohol Content
- Higher ABV can mute perceived bitterness (or just make you not care so much), especially in strong ales or imperial styles.
3. Hop Variety & Usage
- Again, late-hop additions or dry hopping add flavor and aroma, but contribute little to bitterness.
- A hazy IPA may have 50+ IBU, but the use of hops with a juicy/fruity profile can make it feel softer and even taste sweet.
4. Carbonation & pH
- Higher carbonation and lower pH (more acidic) can accentuate or soften bitterness.
Typical IBU Ratings for Common Styles
In case you were dying to know or you like to pad your arsenal for Trivia Night, here’s a quick cheat sheet of typical IBU ranges for various styles:
- Lagers: 8–45 IBU
- IPAs: 40–100 IBU
- Double IPAs: 60–120 IBU
- Sours: 5–10 IBU
- Stouts: 20–90 IBU
- Porters: 18–50 IBU
- Pilsners: 22–40 IBU
- Wheat Beers: 15–30 IBU
Embrace the Bitter With Our South African IPA
At Diebolt Brewing, we don’t just embrace the bitter: we perfect it. (Why did that sound like an ad for a lifted truck?) Our latest and greatest is the “Shazam Effect,” a bold West Coast IPA brewed with 100% South African hops: Southern Tropic, Southern Sublime, and Southern Passion (those last two would be GREAT names for romance novels). This brew balances sweet tropical fruit and berry cream candy notes with unapologetic bitterness. Bottoms up.
Is it just us, or do those two look like Zac Efron and Elle Fanning? Whatever, we’d totally read this.
