What Does IBU Mean For Beer?

Whether you love or hate bitter beer, or fall somewhere in the middle, IBU is helpful brewing terminology to understand when choosing your favorite brewski. IBU, which stands for International Bitterness Units, is, simply put, a scale used to measure how bitter a specific beer is. In general, the higher the amount of IBUs in a beer, the more bitterness it has. Some craft beers will have the IBUs listed on the label, however, you won't necessarily find it listed on every bottle or can of beer you drink and may have to do some digging on the manufacturer's website to find it. 

As most beer drinkers might guess, IPAs (India pale ales) typically have more IBUs and are known for their bitterness, a boon for cooking, as IPAs brings an earthier flavor than other beers. American India pale ales generally have a range of 55 to 70 IBUs (Dogfish Head's 60 Minute IPA, for instance, has 60 IBUs). Compare this to commercial lagers which have a typical range of 5 to 10 IBUs (Miller Lite is rated 10 IBUs). However, it's important to note that there are other nuances beyond IBUs that determine the bitterness of a beer. For instance, beers with high IBUs may have other components — like a higher malt content — that balance out the bitterness and make it taste sweeter than expected. 

Scientifically speaking, IBUs are a measurement of the parts per million of isohumulone in a beer. Isohumulones are chemical compounds found in hops that impart bitterness to beer. While opinions vary, the IBU beer scale generally ranges from 0 to 100, with 100 being a very hoppy, bitter-tasting beer. Some beers claim to have over 100 IBUs, however, according to Sierra Nevada's Senior Quality Advisor Charlie Bamforth, "The highest value you can get is 100, no matter what some people claim." This is because, according to some brewers, your taste buds can't actually discern any additional bitterness above 100 IBUs.

Brewers and scientists have been measuring the bitterness in beer since the mid-20th century and the process has been refined over time. The IBU scale isn't just a promotional tool; it's a highly scientific process that brewers use for quality control to ensure consistent results. The first step involves adding an acid and solvent to the beer sample in order to extract the isohumolones or iso-alpha acids. Then, the solvent is analyzed using spectrophotometry, a measurement of how compounds interact with light. As you can guess, this process requires high-tech, expensive equipment that commercial and large craft breweries have access to. You might not be able to measure IBUs at home but with the help of brewing kits like Mr. Beer's Craft Beer Making Kit or Craft-A-Brew Beer Making Kit it's super easy to make your own, tasty homebrew.