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Debunking “0 IBU” Beer Facts and Falsehoods: 3 Things You Should Know About Bitterness in Your Beer

Published On
January 14, 2020

We list Party Hat as a 0 IBU Hazy IPA. You might be thinking: “How can a beer be 0 IBU?” This is… well, it’s complicated. Many brewers are quick to point out that if you run any beer through a spectrophotometer (that’s spectro-photo-meter) —  the primary tool used to measure IBU —the reading will come back higher than zero, no matter how you’ve designed the recipe. At a minimum it would probably read at least around 7. We stand behind our zero IBU designation and here’s why:

Let’s start with a general discussion of bitterness. There are three important ways to talk about it—perceived bitterness, calculated bitterness, and measured bitterness.


Perceived is a relative scale that measures how bitter a beer tastes based on all the factors that weigh in on bitterness… meaning the sweetness present, plus the real bitterness, any harshness or astringency, etc. Simply put, it’s how bitter it tastes. This is subjective and varies based on how each individual taster perceives these attributes in the beer. A beer can be “0 IBU” and have some bitterness from various hop particulates that aren’t direct contributors to the IBU measure, as well as from the malts used.


Measured comes from that spectrophotomer we mentioned before. It’s a measurement of iso-alpha acids, which are the primary bittering component in hoppy beer, and doesn’t factor in the elements of balance that make things seem more and less bitter (and as we’ll discuss later on, is also flawed.) Technically speaking, if you omit all hopping during the boil, you won’t isomerize any alpha acids because they never hit temperatures high enough for the chemical reaction to take place. However, the spectrophotomer often registers IBUs from non-bittering particulates that don’t contribute to either perceived or calculated bitterness.


Calculated is a simple computation determination based on the written recipe of the potency of the hops and when they are added during the process. As noted above, if you don’t add any hops to the boil, the calculated bitterness contribution from IBUs will be zero because the hops never hit a temperature high enough to isomerize the alpha acids, which are where bitterness traditionally comes from in IPAs.

Get ready… it gets more complicated from here.

The essential thing to understanding why we list this beer as 0 IBU, and some others as very low IBU, is that IBUs are a standard that was designed to approximate, as closely as possible, the bitterness levels of beer—it’s flawed to think of it as an absolute. To make the measurement, the test attempts to measure isomerized alpha acids, the primary bittering component in many beers. While the spectrophotometer provides an absolute number, it’s important to realize that the device cannot differentiate between isomerized alpha acids and certain other particles that are not relevant to overall bitterness. This is why we use the calculated, rather than measured IBU for our beers. This is especially true with beers like Party Hat. Hopsteiner released research a few years ago that draws a straightforward conclusion:

“This test method was not designed for nor did it take into account beers that are heavily dry hopped. Craft brewers performing the IBU test on dry-hopped beers are finding that the IBU test results do not correlate with the bitterness they taste in their beers.”

Further, alpha acids are isomerized by heat, and Party Hat has no hops in the boil. Thus we can say with certainty that it contains no iso-alpha acids, which the IBU scale is designed to measure. Sounds like a 0 IBU beer to us!

The result is a beer that drinks insanely smoothly with a huge juicy, tropical nose, a soft mouthfeel, and an easy finish. Galaxy, Citra, and Mosaic hops without a touch of bitterness… now that’s a guaranteed good time.