by Dr. Carol Westbrook on May 23, 2014

imagesYou will recall from Part I that I decided to home-brew an ultra-hoppy double IPA, inspired by a Christmas gift of Cascade hops. In the previous article, Part I of the Hops project, I reviewed the varieties and chemistry of brewing hops. At that point I had enough background information to ask a few brewing experts for some direction before proceeding on my own.

I got in touch with Jaime Jurado, a good friend who is the Director of Brewing Operations at Abita Brewing Company. I asked him, “How hoppy can you make a beer? What about these beers that advertised IBU’s in the 500’s or higher–are these accurate? Is there a limit to the solubility of the hop oils? Can you even taste the hops at high IBU? Do you need to add more malt, and a higher alcohol level, to make a hoppy beer taste palatable?”

He replied,
“I do not know if 500 IBU is physically attainable…the higher the IBU the more unreliable is the analyses…what we do know is that there is a maximum hop intensity that our palates can detect and discern. My opinion is that balance is always important, so more malt backbone helps balance very hoppy beers, hence the double and triple IPAs out there. But if you ask 10 brewmasters, you’ll certainly receive 14 opinions…maybe more.”

Jaime referred me to a brewer friend of his, Karl Ockert, the technical director for the MBAA (Master Brewers Association of the Americas), who got back to me with:

” …the maximum solubility of the iso-alpha acids is about 120 ppm which means theoretically the maximum IBU possible is about 155.  Sensory wise you probably could not detect any real difference in IBUs above 80 anyway. 

“To make any beer palatable at the high end of the IBU range requires a significant alcohol and dextrin content, hence you see 100 IBU double and triple IPA’s at 6-10% ABV. Ironically the higher the gravity of the wort [e.g., the higher the malt and alcohol content], the less efficient is the isomerization and solubility of the alpha acid. In other words, the stronger the beer the less easy to make it super bitter.

“The analysis loses accuracy at higher BU levels and the breweries representing numbers above 100- 120 are probably using dodgy methods of analysis or relying upon calculated values that ignore the limiting solubility factors.”

In other words, there aren’t any rules, but it’s a matter of taste, and most tasters find that higher hops are balanced with more malt and higher alcohol.

It's Science

It’s Science

Armed with this information and encouragement, it was time to design my hoppy IPA. I decided to modify my standard 6.5% IPA recipe, using 3 additions of Cascade hops over 90 minutes, a fourth at the end of the boil, and a dry hop as well. I would balance the flavor by increasing the dried malt extract by 30%, and add some extra mouthfeel to the whole grain “mini-mash,” with biscuit malt, which has a bread-like flavor. Three additions of hops during the boil, and a fourth during the last 10 minutes, would give me an IBU of about 124. The alcohol level would be about 7.5%. This was my “90-minute Empire IPA,” a single-hop double IPA names for the Michigan hop farm.

I brewed the beer and it was ready by Super Bowl Sunday, which provided the perfect time to taste it and compare to a variety of commercially produced high-IBU beers. I wanted to see if alcohol and malt had an impact on the flavor, and how they compared to my brew.

I picked up seven hoppy craft beers, listed in order from lowest to highest (below), and threw in a Rye IPA to see if the grain type made a difference. (These estimates of IBUs may not be accurate, but I found them on a variety of web sites, so take them with a grain of caution.) I tasted all of the beers during the first quarter of the game with assistance from my husband Rick, accompanied by the requisite wings and chips. We started with the lower IBUs, and worked our way up to the highest. Here it the list:

Victory Hop Devil IBU 50 6.7%
Sierra Nevada Celebration IBU 65 6.8%
Sierra Nevada Torpedo IBU 70 7.2%
Anderson Hop Ottin IPA IBU 78 7.0%
Dogfish Head 90 minute IPA IBU 90 9.0%
Southern Tier 2X IPA IBU 90 8.2%
Six Point Resin Imperial IPA IBU 103 9.1%
Star Hill Double Platinum IBU 180 8.5%
Compared to:
Southern Tier 2X Rye IPA IBU 50-60 8.1%
Westbrook 90-minute Empire IPA IBU 124 7.8%

I do not have the column space to review these beers individually; suffice to say they were all world class; which you prefer is simply a matter of personal taste. The first two beers were typical, big-flavored American IPAs, with Celebration boasting the use of fresh hops. The fresh hops add an herbal or grassy flavor that is mellow and pleasant. As our tasting proceeded up the IBU ladder the increasing bitterness was apparent. Note that the next two, Torpedo and Hop Ottin had more hop bitterness than Celebration and Hop Devil, but about the same degree of malt and alcohol (low 70’s). I thought the hops were a bit harsh-tasting in Torpedo and Hop Ottin, confirming my suspicion that higher malt and alcohol levels were a necessary complement to the taste of hops. The next beers on the list, Southern Tier 2X IPA, and Dogfish Head 90-minute IPA had a much better balance between hops, malt and alcohol. In this middle range, Dogfish Head 90-minute IPA clearly stands out as a world-class beer. However, Southern Tier 2X IPA came in a close second; also well-balanced and very drinkable.

Interestingly, to my palate, the hops in Southern Tier 2X IPA tasted almost exactly the same as those in its less-hoppy cousin, Southern Tier’s 2X Rye IPA. I might conclude that barley malt moderates the hop taste better than rye malt. The hoppiest-tasting beer was Resin, from Six Point–it was quite an experience to drink this beer, which stands out head and shoulders above the others in extreme hoppy taste. The high alcohol gave it an extra kick. Interestingly, Double Platinum claims an IBU of 180, and it was certainly hoppy but not nearly as much (to my palate) as Resin. Was this a trick of good malt and alcohol balance that made Resin taste stronger, or were the measurements inaccurate? I liked both beers, but they were surprisingly different.

indexHow did my homebrew, Westbrook’s 90-minute Empire IPA shape up? It was a damn good beer. Surprisingly, though, it did not taste like it contained 124 IBUs, like Resin, but rather it landed in the middle. In malt taste and hop flavor, it seemed very close to the Southern Tier 2X IPA. I would guess it was about 90 IBU. So my hops and malt were perfectly balanced, but my IBU calculation was a bit off, or my hops extraction was not as efficient as I had hoped. Either way it was a very good beer indeed, and perfect for the Super Bowl game. It paired well with our hot wings and spicy chili.

imagesDr. Westbrook’s invaluable book, Ask an Oncologist is available through Amazon and Barnes and Noble.

{ 1 comment… read it below or add one }

Katharine May 27, 2014 at 6:38 pm

I am a fan of Westbrook Empire IPA, having had the chance to taste it. Nicely done, Dr. Beer! Love that it used Empire hops, which produce some of the best NW Michigan beers, in the area where I live.
I love a hoppy IPA so was paying attention to this article. I wondered about the IBUs question too over the past few years as I turned into a craft beer (IPA especially) lover. But I am a newbie to this, with a lot to learn. Thanks for all the education these articles have provided.


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