If you’re a craft enthusiast, you’ll likely want to know everything there is to know about grading different types of beer. Knowing at a glance what a beer will taste like based on numbers alone would greatly benefit any hobbyist. One of the most perplexing, yet accurate, ways to measure a beer is by its IBU.
In this article, we’ll explain what IBU is, how it’s measured, and what you can expect from a beer with a specific IBU score.
What Is IBU?
First of all, let’s tackle the scientific part of IBU. While this may seem tedious, it’s essential to understand why the scale exists and why we use it.
IBU stands for International Bitterness (or Bittering) Units. The IBU scale is used to approximate a beer’s bitterness, but we’ll get to the “approximate” part later. The scale measures the amount of bittering compound named isohumulone, otherwise known as iso-alpha-acids. Hops contain isohumulone, so there will be a direct correlation between adding more hops to a beer and its IBU score.
Another bittering compound that the scale can allude to, but doesn’t focus on, is beta-acids, or lupulone. While hops contain these acids as well, they don’t add to the bitterness during the brewing process. However, lupulones can oxidize over time, adding a harsher bitterness to the beer’s taste. Due to its unpleasant taste, brewers need to correctly add the best variety of hops to their beer, so that it contains a lot of alpha-acids but a low concentration of beta-acids.
The IBU score will accurately reflect the concentration of humulones in beer after brewing. Still, storage and age will affect the perceived taste due to alpha and beta-acids reacting over time.
How Is IBU Measured?
IBU is typically measured by a process known as spectrophotometry. In this process, hops are boiled to promote alpha acids to isomerize (becoming “active”). The isomerized alpha acids are slightly hydrophobic, allowing them to shift into a specific layer in the boiled wort. The wort will have solutions added to it to promote this process more. After the acids have settled, the wort is brought into a spectrophotometer, which reads the alpha acids’ light absorbance at 275nm. This allows it to determine the concentration of these acids in the wort accurately and, likewise, the brewed beer.
Other methods of measuring IBU are based on a similar principle. These include mass spectrometry, fluorescence spectrometry, and high-pressure liquid chromatography. All of these will yield similar results to scale the IBU score of a beer accurately.
Breweries will have this equipment at their disposal. An IBU score is a good indicator of taste but is also an excellent quality control tool. A brewery with a consistent IBU score for their beers can boast of a high-quality product.
Is IBU Accurate?
Scientifically speaking, IBU is the most accurate way of calculating the bitterness of the beer. However, what IBU doesn’t score is the perceived bitterness. Beers with intense flavors, or those with roasted malts, will have lower perceived bitterness but a higher IBU score. A higher concentration of hops than usual will be required to make them taste more bitter.
Most beers will have an IBU score between 5 and 120, and some unique beers can exceed that. However, the vast majority will sit between 15 and 80on the scale. Higher IBU scores reflect poorly on the perceived taste.
While other factors do come into play, IBU is generally indicative of the beer’s taste. The higher the IBU, the more bitter the beer will be.
High IBU beers
The IBU scale generally goes up to 120. This number is still a reliable indicator of the beer’s bitterness, but anything after is usually left to the beer’s actual taste. The palate has a hard time processing the higher IBU counts, so most beers with high IBUs concentrate on getting the flavor to balance it.
Here are some of the highest IBU scores in existence.
Hoo Lawd by Dogfish Head
This high-IBU beer has been independently tested to have a score of 658. While this may seem astronomical, the brewery has made sure that it remains drinkable. This beer uses experimental hops to allow for a higher concentration of bitterness than normal.
While the beer is no longer available for purchase, you can evaluate just how an IBU score of 658 tastes like by watching this video here.
DCLXVI by Arbor Ales
DCLXVI, which is Roman numerals for 666, is the IBU score of this unique brew. This UK brewery collaborated with Steel City Beers to make this devilish beer at 6.66% ABV.
Although no longer produced, it’s said to taste of citrus, with hints of chocolate and pine.
1000 IBU by Cerverjaria Invicta
This beer has an IBU score of 1000, although it is yet to be verified by an independent source. Still, the taste of it is quite strong, and the brewery suggests pairing this ale with blue cheese like gorgonzola, or salmon. The aggressive bitterness definitely won’t disappoint.
You can purchase this beer on the brewery’s sales page.
Mikkeller 1000 IBU
This European brewery also delivered the self-reported 1000 IBU beer. The surprisingly red color doesn’t mask the lingering bitterness, and it’s reported that you can feel the hops going through your throat.
If you want to try this high IBU beer out for yourself, you can purchase it here.
The Kraken by Triggerfish Brewing
This South African brewery delivered the (self) reported IBU score of 1100. Immediately following their fan reaction, they decided to be more courageous and brew a beer with 1254 IBU.
Taste-wise, the Kraken is a reportedly great experience, with a very fruity aroma and bitter undertone. The fruit and malt do an excellent job of balancing the bitterness, although it does linger for far longer.
This beer is currently unavailable for purchase, but keep your eyes out when they decide to brew another batch, as the Kraken is an experience you don’t want to miss.
Alpha Fornication by Flying Monkeys Brewery
This Ontario-based brewery blew the competition out of the water with their 13.3% ABV, 2500 IBU design. The Alpha Fornication received a minimal, but critically acclaimed run, and it’s uncertain if it will ever make a comeback.
As for the taste, we’re sure it was very bitter.
Our list isn’t expansive but there are great resources to check out if you want to learn more.
IBU is a great way to determine how bitter a beer is, but the method has its limitations. By learning more about the crafting techniques and IBU, you can find the IBU zone you prefer and accurately decide which beers to enjoy. High IBU beers are an experience in themselves, so we hope you have fun trying them out.