The Relative Bitterness of a Modern IPA

For some years now the International Bitterness Unit, or IBU, has been the undeniable and undisputed measurement of a beer’s bitterness — which, technically speaking, comes from the hops’ alpha acids. I won’t go into an explanation of the process — it’s easy to find several links that clearly detail the how and why of the thing. I’m somewhat more interested in one aspect of this scale of measurement: Its empirical character.

The scale extends from 0 to 120. Here are a few reference points: lambic (0-10 IBU); weissbier  (8-15); Munich Helles (16-22); Belgian tripel (20-40); strong bitter (30-50); American IPA (40-70); double IPA (60-120). The rating is the result, in parts per million, of the isohumulones in a given volume of beer.

But the fact remains that taste is mainly a matter of perception.

Consider, for example, this Modern IPA, from Eviltwin Brewing, which has two headquarters (Copenhagen and Brooklyn) and was founded in 2010 by Jeppe Jarnit-Bjergsø.

This IPA titrates 6% ABV and 65 IBUs, which puts it within the range of an American IPA, but already beyond that of an English IPA (40-60). And therefore, let’s move in that direction. You can taste an American pale ale rated 50 IBU which will barely give you the impression of being bitter. And you can taste this Modern IPA, which will immediately give the impression of radical bitterness. The difference between the two: 15 small points on a scale of 120…

What I want to underline here is this: The IBU scale is above all indicative. What the palate perceives does not always fit with the calculated rate of bitterness. Yet, fortunately, there is no scale unit for aromas and flavours. Because, in the end, tasting a beer remains eminently poetic.