International Bitterness Units (IBUs): A Comprehensive Guide and Style List

Find out what international bitterness unit's (IBU's) are and read our useful list of IBU ranges by beer style.

BEER

Mat Stuckey

9/13/20234 min read

three filled glasses on gray surface
three filled glasses on gray surface

International Bitterness Units (IBUs): A Comprehensive Guide and Style List

When browsing beer selection, you've likely encountered the term "IBUs" used to denote a beer's bitterness level. But what exactly are IBUs and how are they measured? This article explains the International Bitterness Unit scale and includes a handy IBU range list across popular beer styles.

What Are International Bitterness Units (IBUs)?

International Bitterness Units (IBUs) are a numeric scale that quantifies the bitterness level present in a beer. Specifically, IBUs measure the concentration of isohumulone, which is a chemical compound derived from hops that lends bitterness to beer.

The IBU rating indicates the total parts per million (ppm) of isohumulone in a finished beer. For example, an IBU rating of 30 means there are 30 ppm of isohumulone, which would taste moderately bitter.

Why Use IBUs to Measure Beer?

The development of the IBU scale by brewing scientists provides several useful functions:

  • Quantifies bitterness - Puts a numeric value on the subjective bitterness tasted.

  • Compares styles - Helps bracket styles into expected bitterness ranges.

  • Adds technical understanding - Provides brewers and drinkers more precise bittering data.

  • Sets expectations - Gives drinkers a sense of how bitter a beer may taste.

Having an objective lab measurement for bitterness helps provide a common terminology when describing and differentiating beers.

What is the IBU Measurement Scale?

The IBU scale was designed to encompass the full range of bitterness perceptible to the human palate. It spans from 0 IBU on the low end to over 120 IBU at the very high end:

  • 0-15 IBU - Little to no bitterness. Mostly malty sweetness perceived.

  • 15-30 IBU - Low end of balanced bitterness. Detectable but not harsh.

  • 30-45 IBU - Moderate bitterness emerging. Starts coating the tongue.

  • 45-60 IBU - Bitterness quite pronounced but still balanced by malt.

  • 60-100 IBU - Very high bitterness that dominates the palate.

  • 100+ IBU - Extremes of bitterness. Hard for tongue to detect much over 100 IBU.

How the bitterness presents itself also depends on the beer style and balance of flavours.

Typical IBU Ranges By Beer Style

While individual beers may vary, here are some general IBU guidelines across popular beer styles to set expectations:

  • English Mild - 10-25 IBU

  • Hefeweizen - 10-15 IBU

  • Blonde Ale - 15-28 IBU

  • Bitter - 25-45 IBU

  • English IPA - 40-60 IBU

  • American Pale Ale - 30-50 IBU

  • Amber Ale - 25-40 IBU

  • Porter - 25-50 IBU

  • California Common - 30-45 IBU

  • American IPA - 50-70 IBU

  • Double IPA - 60-120 IBU

  • American Barleywine - 50-100 IBU

  • Imperial Stout - 50-90 IBU

See how styles group into low, moderate, or high bitterness ranges.

IBU List of Commercial Beer Examples

To further illustrate the styles, here's an IBU list with popular commercial beer examples ordered from low to high bitterness:

  • Budweiser (American Lager) - 8 IBU

  • Stella Artois (Pale Lager) - 18 IBU

  • Blue Moon (Belgian White) - 10 IBU

  • Fuller's London Pride (Best Bitter) - 20-25 IBU

  • Sierra Nevada Pale Ale - 37 IBU

  • Lagunitas IPA - 51 IBU

  • Founders All Day IPA - 42 IBU

  • Stone IPA - 77 IBU

  • Ballast Point Sculpin IPA - 70 IBU

  • BrewDog Punk IPA - 40-50 IBU

  • Fat Head's Head Hunter IPA - 113 IBU

  • Goose Island Bourbon County Stout - 60 IBU

  • Arrogant Consortia (Double IPA) - 100 IBU

  • De Molen Hemel & Aarde (Double IPA) - 100+ IBU

This demonstrates the style diversity at different bitterness levels.

Why Don't Higher IBUs Always Taste More Bitter?

Surprisingly, two beers with the same IBU count can taste very different in bitterness due to other factors like:

  • Malt sweetness - Rich malts balance out hop bitterness, perceiving less harshness.

  • ABV strength - The warming sensation of higher alcohol contents softens bitterness.

  • Residual sugars - More unfermented sugars mask bitter sensations on the palate.

  • Hop varieties - New World hops taste much more bitter than European noble hops.

  • Dryness - Thinner body and crisper finish accentuate bitterness than a thick mouthfeel.

  • Adjuncts - Oats, wheat, and rye soften the bitterness perception.

A balanced IPA and boozy barleywine can hit 70 IBUs but taste worlds apart. IBUs alone don't tell the whole story.

Should Drinkers Focus on IBU Count?

For brewers, carefully tracking IBUs during design and brewing helps achieve the intended bitterness targets. However, for beer drinkers, don't get too hung up on the IBU number. Instead:

  • Note the style - That sets the expected bitterness range.

  • Consider the brewery - Their philosophy gives clues to intensity.

  • Sample before judging - The taste ultimately matters most.

  • Discover your preferences - Try different styles to learn your ideal bitterness.

While IBUs provide bittering data, the knowledgeable beer drinker weighs that amongst the beer's overall balance and their personal flavour affinities.

Conclusion

As a key chemical compound derived from hops, isohumulone is the source of bitterness in beer. By measuring isohumulone parts per million, the International Bitterness Unit scale provides brewers and drinkers an objective measure of beer bitterness. IBUs help differentiate beer styles into low, moderate, and high bitterness ranges. However, don't overlook the importance of a beer's overall balance and your personal taste in judging bitterness. Consider IBUs just one metric on an informed beer journey.



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