I’ve been thinking a lot about IBUs. It all started quite innocently. I was recently bellied up to the bar at my local pub, as I’m known to do, and I couldn’t help but overhear a group of young men perusing the admittedly impressive list of libations scrawled onto the chalkboard in front of them, discussing their options and the various characteristics of each beer. Style. ABV. Locality. Rarity — a litany of qualifiers and descriptors that would make a NASA scientist blush.
“Oh nice, that’s the new one from Vermont.”
“I had a great version of a doppelbock the other night. I want to try this one too.”
“I have to get back to the kids by 5 p.m. I need to keep the ABV down.”
I’m clearly paraphrasing here, but it’s a conversation that I have, with my friends or by myself, quite frequently. A healthy and vigorous discourse about your beer choices is encouraged, and this author won’t hear another word about it.
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But this would be a very boring article if I hadn’t skipped one major detail about their conversation that, honestly, irked me a bit.
They finished almost every one of those sentences I just mentioned with a withering and patronizing assessment of each beer’s “pitiful” number of IBUs. The red ale didn’t have enough IBUs. The stout didn’t have enough IBUs. The IPAs — THE IPAs for heaven’s sake — didn’t have enough IBUs.
I will tell you as someone who works as an educator and (amateur) writer in the beer industry, it wasn’t easy for me to listen to this conversation without butting in with a few well-chosen, and polite remarks. I kept my silence, and instead took the time to do a little more research into everyone’s favorite acronym. International Bitterness (or bittering) Units, or IBUs, are undeniably interesting, and as we’ll find out here, often misunderstood in the cacophony of conversation around the modern beer industry in 2017.
We’ve all seen it by now, but it pays to mention how often you see IBUs sitting on beer labels, bar menus, and across the various media we all absorb as self-obsessed beer fanatics. They are everywhere. In fact, most modern craft breweries describe the style, ABV, and IBUs on their label artwork and designs, along with a few select mouth-wateringly delicious adjectives to wet your whistle. Juicy. Hazy. Dank. Fresh. Thirsty yet? I am.
I’m picking on IPAs here, which I like quite a bit in all fairness. Their dominance in the craft category has been well documented at this point, but they really embody a lot of the misconceptions around how and why brewers invented the IBU in the first place, and its actual use in today’s brewing process.
Beer, in its modern form, is a beverage meant to satisfy almost all your senses. It’s visually stimulating. The aromas are fresh and evocative. The taste is often complex when you break it down. The carbonation, the temperature, the viscosity…all factors that contribute to a wonderful experience and perception around the product in your hand.
The key to that last paragraph was “perception” because that’s really all the matters to me as a beer drinker. Ostensibly, the heuristic assessment of a given experience is almost completely dominant when you think back on it one, two, or three days/weeks/months later. Did you enjoy it? Did you like it? Would you want to do it again? These are the questions that really matter. It’s sort of like a great wedding — you may not remember the color of the napkins or the way the asparagus was cooked, but you do know you had really great time, and that perception will stick with you forever.
I’m generalizing here, so let’s wind it back for a minute.
Origin Story of IBUs
I wrote a separate article on this very subject for my site a few years ago, which inspired me to get a few industry experts on the record to hear their take in 2017. But before we can go any further, I should quickly define what an IBU actually is.
Actually, let’s have Dr. Tom Shellhammer, one of the world’s leading hop researchers and the Professor of Fermentation Science at Oregon State University, define what an IBU actually is. I was able to catch up with him briefly to get the most accurate definition. Full disclosure — this gets really science-y.
“International Bitterness Units are a chemical/instrumental measurement of the number of bittering compounds, specifically isomerized and oxidized alpha acids, polyphenols, and a few other select bittering chemicals, that make your beer taste bitter. The IBU correlates well, in most cases, with the sensory bitterness of beer, and this is why brewers use it. Almost all the beer you’ll ever drink will have a measured IBU between five (which is a very low measured bitterness) up to 120 (which is a very high measured bitterness). Most beer falls in a narrower range within these parameters (between 15-80ish), but that’s the gist of it.”
The Craft Beer Industry
You can’t talk about IBUs without asking some of the American breweries that pioneered great quality control techniques in craft beer over the past 30 years, and their subsequent use of IBUs to determine consistency and bitterness batch over batch.
Meghan Peltz, sensory manager at Sierra Nevada, exploded my brain a little bit when I asked her about the calculation methods used to determine IBUs and Sierra’s use of them during their brewing process.
“There are a few ways to measure IBUs,” said Peltz, “But it’s not a strictly regulated statistic in brewing.”
Peltz continued, “You can make a fairly good educated guess on the number of IBUs based on the alpha acid content of the hops used in the brewing process. It’s a quick calculation based on the volume of hops and the conversion rate of the alpha acids in the kettle.”
So what does Sierra Nevada, with its robust quality lab and expert staff, use to measure IBU counts?
“We use the Spectrophotometric method,” said Peltz. “This measures all of the bittering compounds in the beer quite accurately.” This includes those oxidized acids and polyphenols we mentioned earlier. It was a method invented in 1950’s, and here’s how it works in a nutshell: You take a sample of beer, which is full of bittering compounds. The bittering compounds are “hydrophobic,” which means that they are not necessarily happy to integrate into the surrounding liquid, which is mainly water.
Peltz goes on: “You add some acid to the beer sample, which really makes them not want to stay in the beer. On top of that, when you add a non-polar solvent to the mix, it causes all of the bittering compounds to move from the water/beer phase into the non-polar solvent phase. You shake it for 15-30 minutes to ensure good mixing and make sure the bitter components are in the non-polar phase, take a sample of the nonpolar phase (which now has the bitter compounds in it) and then put it in the spectrophotometer. The spectrophotometer shines a specific wavelength of light through the sample, in this case, 275 nanometers (which is in the UV range), and measures how much light was absorbed. That absorbance value multiplied times the factor ’50’ is the IBU.”
Badabing, badaboom — you’ve got the measure of IBUs in your beer, using industrial grade acids, polar solvents, and a spectrophotometer.
Another West Coast brewing stalwart, Stone, has a similar take on their use of IBUs in the brewing process. I spoke with Steve Gonzalez, senior manager of Small Batch Brewing & Innovation at Stone Brewing Company.
“IBUs are really interesting, but for the most part, we try not to emphasize them too much in anything consumer-facing,” said Gonzalez. “It’s not really relevant to your enjoyment of the product, and we’re constantly hearing about IBUs across the industry being used an important stat when describing beer. Stone uses IBUs as an important quality control too, like most breweries, and while the consumer certainly wants to see it, we’re not making new beers to hit a certain IBU threshold.”
Perception vs. Reality
So why does this all matter anyway? IBUs, which started as a quality control tool, have evolved into a stalwart of consumer statistics over the past 10 years, and what would seem to be a vital marketing tool in the arsenal of numbers plastered on the outside of any new beer entering the market.
Remember when I mentioned perception? The actual enjoyment of the beer in your hand?
The jury’s still out on my opinion here, and I’ve heard a lot of valid arguments against this idea from very notable figures in the beer industry, but the main issue with touting IBUs as a marker of a “good beer” according to that group of guys I mentioned at the beginning of this article, is a very basic one: IBU counts do not a great beer make, and what’s more, your perception of these IBU counts are often completely at odds with the actual measurement of the beer.
Since I spoke with Sierra Nevada, I’ll use their style-defining American Pale Ale and their stout as a perfect illustration of my point. My perception of Sierra Nevada Stout is that of a rich, roasty liquid with bitter and sweet balanced out relatively well. My perception of Sierra Nevada Pale Ale is that of bold, bright pale ale, with a great balance of its own, but obviously hop-forward.
I wouldn’t personally describe Sierra Nevada Stout as “hoppier” or “more bitter” tasting than Sierra Nevada Pale Ale. And therein lies the rub:
- Sierra Nevada Pale Ale: 38 IBUs
- Sierra Nevada Stout: 50 IBUs
Their stout has more bittering compounds, and is empirically “more bitter,” but I don’t personally perceive it that way. Certainly, the stout has a notable bitterness, but I would say that the bitterness of Sierra Nevada Pale Ale, according to my palate, is more apparent, and the beer was obviously designed to be that way in the first place.
I can point to many, many examples of how IBUs would mislead your initial conception of how a beer should taste, at least according to the general population’s common misconception of what they mean and how they’re used. Meghan Peltz and the team at Sierra Nevada use them as a very important factor in checking consistency at the brewery.
“IBUs are important for us to check against the recipe that had been planned. Our brewers will target an IBU count and target a certain alcohol, malt bill, and flavor to really deliver on what the aim was when we started. It’s good for quality, and by checking multiple batches, we can check the deviation in the batch itself,” she explains.
For a brewery like Sierra Nevada or Stone, and their national distribution footprint, this makes perfect sense.
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Why it (doesn’t) Really Matter
Beer drinkers’ fascination with IBUs, in all their glory, seem like they’re here to stay, but that might miss the point.
The point of great beer, any great beer, is that you enjoy the liquid in your hand and understand the true vision of the brewer with every sip, along with the story behind the brewery and their motivations for making the product in the first place. Beer, in its science and its art, is the composition and combination of balance and intention. Water, malt, hops and yeast in perfect unity. Poetic stuff.
To that end, great beer is about your perception, and on the topic of bitterness and hoppiness (which are, by themselves, very different), perceived bitterness is very different from actual, measured IBU counts in a lot of cases. I don’t hate IBUs by any means, and I do think they can be generally indicative of how “hoppy” or “bitter” a beer will be in a lot of cases, but I think a more judicious use of them on our beer labels and in our conversations will help us truly appreciate what we’re consuming, and why it even matters in the first place. At the end of the day, IBUs do not indicate flavor, aroma, perceived bitterness, or really any other factor that allows you to actually enjoy the beer your drinking, but they are part of the industry, and it’s worth knowing a little more about them.
Hopefully, this piece helped you understand a little bit more about why they’re used, what they mean, and how they impact your enjoyment of all the great craft beer available right now.
And to the guys at the bar who wouldn’t drink anything under 70 IBUs: drop the pretense, ask the bartender for a quick sample, and call me in the morning.
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