Shove your IBUs
Definitely the craft beer movement is fascinated with hobs. Hand in hand with that is its obsession with hob derived bitterness. So you may have noticed on beer labels the measurement IBU and wondered why.
What is IBUs and Are They Useful?
International Bittering Units (IBUs) is a brewer’s tool to help achieve taste consistency across batches. Hop harvests (either fresh or otherwise) fluctuate in their chemical composition, as any natural product does. Pre-calculating individual hop addition IBUs, and adjusting dosage amounts of hops accordingly, is important for commercial quality control. IBUs isn’t a general measurement of beer bitterness. It is a measurement of just one bitterness source, isomerised alpha acids, and it is measured using a spectrometer that looks at the absorption of light at certain wavelengths. While the whole process is awfully scientific, there are a few simpler methods of estimating the amount of alpha acids that are extracted into the final beer. One being the below equation:
IBU = (W x U% x A% x 1000) / (V x C)
Where W = Weight in grams of hops
U% = Utilisation factor of gravity of the boil
A% = Alpha acid percentage of alpha acids in the hop
V = Volume in litres of the final wort
C = Gravity of the boil, a correction factor if the specific gravity is higher than 1.05. When the specific gravity is higher than 1.05 then
C = 1 + [((the gravity of the boil) – 1.05)/2]
Sorry. I did promise a simple equation but that’s about as simple as it gets.
Unfortunately the equation is limited in application. Its major flaws are it doesn’t take into consideration 1. Varying rates of isomerisation of alpha acids; 2. Extraction of alpha acids at any other point in the process; 3. The significant role dry hopping is having in craft brewing and its release of bittering beta acids; and 4. It ignores beer bitterness gained from other sources. The IBUs in entirety doesn’t correlate to human’s perception of bitterness.
The IBU was never intended to be used by marketers on labels and pushed into the consumer world. It is not an accurate indication of a beer drinker’s experience. The bitterness you actually taste, perceived bitterness, is greatly affected by how all the major flavours are balanced against each other: bitter hopping with malt sweetness/dryness against yeast flavours and hop aromatics. You can have two beers, of the same IBUs, and one will taste bitter and the other won’t, owing to the flavour balancing. The IBU measure is most useful for brewers to maintain hop bitterness consistency batch to batch with the same recipe when hop specifications of alpha acids fluctuate over time and between suppliers.
How Much is Too Much Hops?
Well… opinions certainly vary on this. For a hop head the answer would be ‘NEVER!’. There is technically no maximum but the level of bitterness does get to a point that it is too bitter to enjoy.
Source: Craft Beer Carl - Meme Generator.
While bittering hops can stick out like balls on a bull, they shouldn’t gore you like a minotaur. Individual thresholds of what is goring and what isn’t is subjective, but it’s safe to say you’re out on a limb if your hunting a beer with an IBU of 1000, when most agree a beer of 120 IBU is very bitter. The average beer has an IBU of 15 to 80.