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4 Reasons Not to Rely on the Craft Beer IBU Scale

by Bud Estey
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  In this article, I will prove that the IBU rating scale does not necessarily indicate the bitterness in the actual TASTE of your beer.  

   In my years of homebrewing, I have seen many variables that would make a brew’s bitterness less intense even though the IBU was still relatively high.  What are these variables?  Let’s dive right in and bring them to light.

 

What is IBU?

 

 

 

 

   I believe we should start by understanding what IBU means.  The abbreviation stands for  International Bitterness Units.  IBU is simply a gauge used to rate the bitterness of a beer.  IBUs measure the parts per million of isohumulone found in a beer.

   Isohumulone is an acid found in hops that gives beer that distinct bitter taste.  The IBU scale is used as a general guideline to measure the amount of isohumulone found in the beer. The lower the IBU rating is, the less bitter the beer will taste and vice versa.  But as I mentioned earlier, some variables can mask that bitter taste in your beer.  I will discuss 5 of those variables, but please understand that there are many others besides these. 

 

Brewing Variable #1: Malt

 

   First, we need to talk about malt or maltose.

   So, what is maltose?  According to homebrewadvice.com, “Maltose is of particular importance while brewing beer, as it constitutes most of the digestible sugar which is formed by the malting of the grain, and subsequent digestion of the starch content of the malt.”

 

   Malt is the sugar that the yeast feeds on to cause fermentation in a batch of wort, which becomes the beer.  The quote goes on to say, “When maltose is metabolized with yeast, it becomes fermented, and the result hereby is ethanol and carbon dioxide.”

 

   A Gravity/Hops Ratio chart shows that the more malt used in brewing, the higher the gravity, which means the amount of fermentable sugar will be present in the brew.  The higher the gravity, the more the hop’s bitterness will be masked.   So even though the  Isohumulone acid is still there, creating a higher IBU… the bitter taste isn’t as noticeable.

 

Brewing Variable #2:  Hops and Taste Perception

   I read that there are approximately 80 varieties of hops available on the market today, and new hybrids are being developed every day, so that number is not set in stone.  Each type of hop has its unique quality and uses for creating different beer styles.

 

 Varieties of Hops

There are many different types of hops:

  • Bittering Hops such as Admiral, Bitter Gold, and Chelan.   

  • Aroma Hops like Amethyst, Bianca, and Canterbury Whitebine.

  • Dual-Purpose Hops such as Amalia, Bobek, and Cashmere.

 

   Bittering hops tend to have a high amount of acid, imparting that recognizable bitter flavor into the beer. Therefore, the more acid present in the hops, the more bitter your beer will be.  

 

   American hops, such as Citra, produce a light sweetness, peach, lemon, and tropical fruit characteristics. Simcoe hops are loaded with dank pine, wood, and musky features.  

 

   These hops varieties will produce a different taste perception in each person’s mouth.  For instance, Dogfish Head 90 Minute Imperial IPA has a 90 IBU rating, and in my experience tasting it, I would have to say that it has a very bitter taste.  Not a bad thing; it's just how my tastebuds perceive the taste.  I have also tasted Treehouse Brewing Company’s Haze, also listing a 90 IBU rating. However, haze has nowhere near the same bitterness that Dogfish Head 90 minute has.

 

   Treehouse Brewing also makes another 90 IBU-rated beer called Green. There is a review on the Untappd app that I found interesting.  “Made with Australian and American hops, this heavy tropical tasting IPA opens up in the glass with hugely flavorful notes of lemon-lime, pineapple, orange sorbet, and tangerine. It has a soft but pointed bitterness and a rich, velvety mouthfeel. Intensely kettle and dry-hopped yet balanced and flavorful…”  

 

   The key phrase in that description is “dry-hopped yet balanced and flavorful.”  It doesn’t say, “pucker your lips, scrunch your face, and close your throat bitter,”… instead it says, “balanced.”  

 

   Brewers will use different varieties of hops, add other ingredients, different amounts of “this or that,” which will create a different taste perception across the tongue of bitter or not so bitter even though the IBUs are the same.

 

Brewing Variable #3  Boil Time and Dry Hopping

 

   We have to consider the length of time a batch of wort is boiled and how that will affect the acids in the hops.  This process may also change the flavor.  I believe that Joshua Bartlett of the Learning to Homebrew blog site says it best.  

 

“When the wort is hot and boiling, added hops will burn off their essential oils, and their chemical composition will change: Isomerization of the a-bitter acids in hops results in the transformation into iso-a-acids. This is where the bitterness comes from and is also why you add your bittering hops early into the boil. The longer your hops are boiled, the more bitter your beer will be because of this chemical reaction.”

 

  The longer you boil the wort, the more acid is released from the hops; therefore, the higher the IBU will be, thus resulting in a more bitter taste.  So far, we are all well and good.  Standardized tests are now run during the boil to calculate the level of acids found in the wort to determine the IBU outcome.  The industry does this during the “early boil.”  But what happens when dry-hopping occurs?  

 

   Ross Koenigs, the director for research and design at New Belgium Brewing, said, “Current IBU tests only measure one way of using hops — the early boil addition to get bitterness from isomerized alpha acids.

The chemistry doesn’t accurately take into account bitterness derived from late hop additions or dry-hopping.”

 

   An IBU test is performed during the early boil, and then more hops are added for dry-hopping later in the boil. Could that change the IBU?  There is also the length of time the hops are boiled during dry-hopping and the amount of acid released at that time. Something wrong with this picture.

 

Brewing Variable #4:  The IBU Scale is a Sham!

  1.  I know that the status of the IBU scale is not really a “Brewing Variable,” as stated in the above subheading, but I’m sure you get the point. 

  2. The idea that the IBU scale is a sham is not my contrived ideology.  So please don’t accuse me of such.  I am just reporting the information that is out there.

 

   I read a fascinating article by John Frank of the Denver Post titled, “The myth of the IBU scale and what some Colorado breweries are doing about it.”  One of the Colorado breweries mentioned in this article happens to be New Belgium Brewing, where Ross Koenigs (quoted above) works. This is not a happy coincidence.  I got the quote above from this article.  Let me show you a couple more excerpts from that same article.

 

“The newest research — including a recent experiment conducted by Colorado breweries — reveals that International Bittering Units (known more commonly as IBUs) is not a good measure of bitterness in IPAs.”

 

“The traditional way of measuring bitterness is not relevant, or accurate, or even useful,” said Neil Fisher, the head brewer and owner at WeldWerks Brewing in Greeley.

 

   The article contains quotes from people who are considered professionals in the industry.  They know what they are doing and what they are talking about. Therefore, we should pay attention to what they have to say.

 

   I am asking you to consider all of the information you have read and then make your own decision.  We need to use a little common sense.  If you purchase a double IPA, you should expect it to have a more pungent bitter taste than a standard IPA.  Many breweries do not put an IBU rating on their beers anymore, and I am good with that.  How about you?

 

Time to Hear From You

 

  • Do you agree or disagree with this article?

  • Do you depend on the IBU rating when considering a beer?

  • Or you don’t give a #%@& about any of this and just drink beer?

Leave me a comment below.  Please take a moment to visit my FacebookInstagramTwitter, and YouTube channel.  Subscribe, like, share, and all that brouhaha. 

 

Thank you for your time, and I look forward to hearing from you.

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What is IBU
Variable 1
Variable 2
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