2nd Round of IBU Testing Results (6 Beers...)

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2nd Round of IBU Testing Results (6 Beers...)

Post by Scott » 6 months ago

I posted results from my first round of IBU testing results several months ago, same "Hopping". Below are my most recent results. Testing date was last Monday, 3/20/3017.

When people have their beer tested, frequently / normally it winds up low in IBUs, and frequently the home brewer blames bitterness estimation formulas (Tinseth, Rager, Garetz, etc.), which of course are not perfect... Would the formula(s) be more accurate if they used "just tested" fresh hops, where they could trust the listed AA number more? I think so... :think:

I believe it is as much or more due to loss of AA in the hop because of age, storage conditions, and storage temperature. Different varieties are better than others in maintaining Alpha Acid. Most Brewers make no adjustment for this... I used my Alpha Acid (AA) estimation Excel formulas / spread sheet (most recent version) on all of these to try to get a "closer" estimate and believe it to be a help, better than taking the AA listed on the package. Goes back to my question on "Do Hops Lose AA Content"...from a year or so ago: http://www.biabrewer.info/viewtopic.php ... 9c820bcca2. The current spreadsheet is obviously not perfect, and never will be, but for me is better than taking the posted AA on the package.

Price tag for these laboratory AA tests went up to $15 each...and 6 samples means $90 US... May need to be more selective on beers I want to test. Still the testing results are interesting.

Past Testing Link: http://www.biabrewer.info/viewtopic.php ... 9c820bcca2

All hops were northern hemisphere US hops, and I estimated September 1st of the harvest year for the AA test date, and then had approximate storage temperatures and months in each storage condition that were input into my AA estimation spreadsheet. With making adjustments, Hop quantity was INCREASED to account for loss of AA over time. Without these adjustments, actual tested AA would have been lower.

Sample 1:
German Bock Lager
Brew Date: 16 September, 2016
OG: 1.067, FG: 1.018, ABV: 6.3%
2015 US Magnum Hops, 14.7% AA adjusted to 13.9% AA (75 min)
IBU (Tinseth Estimate): 36.0
Actual IBUs Tested: 28.0 (+/- 0.5)


Bock Notes: Turned out very well and definitely want to make this again! Tried to match up to the original, Einbecker Urbock Dunkel as well as possible, including its IBU level - which is higher than the Bock from Munich (perhaps because of Munich's harder water, which I understand will accentuate the bitterness in hops). Hops seem in balance...but will likely shoot for 36 again when I brew it again. That would be good too. Beer has tons of malt body and could handle more...although good "as is". With only 43 grams / 1.5 ounces in the hop bag, don't understand why IBU was so low.

Sample 2:
Sterling Bohemian Lager
Brew Date: 6 October, 2016
OG: 1.053, FG: 1.015, ABV: 4.9%
2015 Sterling Hops, 6.8% AA adjusted to 5.5% AA (75 min, 30 min, 10 min, & 0 min)
IBU (Tinseth Estimate): 40.6
Actual IBUs Tested: 33.0 (+/- 0.5)


Sterling Lager Notes: I got lazy on this... Several month old Urquel yeast "sloppy slurry", a nice size jar. Pitched it without making a fresh starter to get things going... Oops. Was really slow to take off, and FG finished a tad high... Not hoppy enough. I often blended this with a German Pilsner for a better balanced overall beer. (The German Pils turned out good but pretty hoppy).

Sample 3:
Dark Czech Lager
Brew Date: 29 October, 2016
OG: 1.055, FG: 1.014, ABV: 5.3%
2015 Sterling Hops, 6.8% AA adjusted to 5.5% AA (75 min & 5 min)
2015 Cz Saaz Hops, 3.2% AA adjusted to 2.3% AA (5 min)
IBU (Tinseth Estimate): 27.9
Actual IBUs Tested: 34.0 (+/- 0.5)


Dark Czech Lager Notes: Inspired by U Fleku, info I could find about it (a "Tmave Pivo"). Turned out nice. Used the freshly used Urquel yeast from the Sterling Bohemian Lager and it worked out well. Like a blend of a Munich Dunkel and a dry Irish Stout. Not super hoppy...

Sample 4:
German Pilsner
Brew Date: 20 November, 2016
OG: 1.055, FG: 1.014, ABV: 5.3%
2014 Santiam Hops, 6.9% AA adjusted to 3.9% AA (FWH @ 110 min, 10 min, 1 min)
2015 US Magnum Hops, 14.7% AA adjusted to 13.3% AA (5 min)
2015 Mt. Hood Hops, 6.1% AA adjusted to 5.9% AA (should have went 5.7%; 75 min & 15 min)
2015 Liberty Hops, 4.8% AA adjusted to 3.4% AA (5 min)
IBU (Tinseth Estimate): 39.0
Actual IBUs Tested: 40.0 (+/- 0.5)


German Pilsner Notes: Turned out well. Initially at times thought it was a little too hoppy, but now (in March, after 4 months) it is very nice. Lots of late hop additions... In future I will experiment with even more late hop additions, at flame out & hop stand... I discussed results on Sterling Lager vs. German Pils here, "Tale of Two Pilsners": http://www.biabrewer.info/viewtopic.php ... 0be1414739

With APA samples 5 & 6, all done the same except for yeast. One finished with Wyeast 1056 American Ale Yeast (very clean) and the other with Wyeast 1332 Northwest Ale Yeast (more of a British-ish style). I wanted to see if differences in fermentation made a difference in final IBUs, and one of the testing results I read recently (...Brulosophy???) indicated final bitterness can be affected by different yeast in fermentation.

Samples 5 & 6:
American Pale Ale - 2 each
Brew Date: 14 January, 2017
OG: 1.053, FG: 1.011, ABV: 5.4% - Wyeast 1056
OG: 1.053, FG: 1.012, ABV: 5.3% - Wyeast 1332
2014 Columbus (CTZ) Hops, 15.3% AA adjusted to 8.2% AA (75 min)
2016 Cascade Hops (home-grown), estimated @ 5.0% AA (10 min & 0 min)
2016 Cenntennial Hops (alternate source), estimated @ 9.0% AA (Dry-Hop)
IBU (Tinseth Estimate): 40.0
Wyeast 1056 American Ale - Actual IBUs Tested: 52.5 (+/- 0.5)
Wyeast 1332 Northwest Ale - Actual IBUs Tested: 54.0 (+/- 0.5)


American Pale Ale Notes: They are similar but slightly different... They seem pretty hoppy but not out of line. According to IBU test results, they are out of range of APA (30 to 45 according to notes in Brewing Classic Styles book)... Oops. Notes I have on CTZ show it losing 48% of its AA in 6 months @ 68 deg F / 20 deg C (standard hop industry test). Most likely it didn't lose as much AA as estimates showed. Either that or my Cascades were considerably higher than the 5% AA that I estimated...or both. Actual lab tested IBUs of the two APA samples were close - but just beyond the supposed margin of error. Unsure if that has to do with fermentation, chance, or whatever...

With Hop level adjustments, it feels like I am closer to target... But now was over as often as was under.

Pat has recommended the idea of using a Hop tea and actually tasting it...and making your adjustments and whatnot based on that. This is likely a tool that professional Brewers use. (???) Cool idea if you have a large batch of hops (pounds worth, not ounces). Not very practical if we buy hops in smaller quantities, I think. (Would use most of your hops making the tea unless you bought a large bag worth...and maybe buying larger quantities and tea is the best idea). :think:

Interesting... :smoke:
Last edited by Scott on 26 Mar 2017, 23:48, edited 6 times in total.


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Re: 2nd IBU Test on Beer (to Help Determine Hopping Levels...)

Post by Streamer » 6 months ago

Wow. Nice work Scott. Do you detect a pattern in the numbers?

I can't tell if you are going down a really deep rabbit hole or on the verge of mastering one of the dark arts, but this is really interesting stuff.

Thanks for all the effort you put in, and for sharing it.
Who controls the past controls the future. Who controls the present controls the past.

George Orwell


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Re: 2nd IBU Test on Beer (to Help Determine Hopping Levels...)

Post by Scott » 6 months ago

You know Streamer, I think it's a bit of both... (Going down a rabbit hole and gaining some greater level of understanding). :|

Have revised my initial post some for (hopefully) better clarity.

As far as patterns, after always adjusting hops now - I'm not underhopped on everything like the first time testing. That's good.

The "next step" probably needs to be buying large enough volumes of hops to be able to make Hop teas, and taste them that way too. Could likely add another "layer" of knowledge. I do smell them of course, but that doesn't help a ton...other than thinking "I like this Hop"... And smelling is tasting. So will tasting an actual Hop tea like Pat suggested help...? Worth a shot. I've got a couple varieties in large enough amounts to give this a try... ;)
Last edited by Scott on 26 Mar 2017, 01:15, edited 1 time in total.


Topic author
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Re: 2nd IBU Test on Beer (to Help Determine Hopping Levels...)

Post by Scott » 6 months ago

Streamer, got your PM. Sorry, I had not attached any of my recent "refinements"... Little things to make it easier to use. And I understand that it's possible some of the drop downs (etc.) may not work in all systems. Works in my Excel program.

I think it's better than not, when guessing AA drop, but by all means use any other methods at your disposal to make sure you dial in a proper AA. I've proven by the above testing that it isn't perfect either - just (to me) better than taking the AA off the hop packaging or guessing.

Example: How I use it.
111916-Santiam.xlsx
Clean File:
Alpha Acid Loss Over Time Estimate - 111416.xlsx
Hope it helps! Let me know.
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Topic author
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Re: 2nd Round of IBU Testing Results (6 Beers...)

Post by Scott » 1 month ago

I did a third round of IBU testing a couple months ago. Not going to bother listing results here... All of the beers were hop pellets, and all resulting beers had too high an IBU, after doing the adjustment using the formula I had. It has caused me to lose confidence in using the formula to a large extent, perhaps unless I'm using flower. Likely hops pellets keep good longer, even when both are stored properly. I've done a minor adjustment in times since with pellet hops, but not as large an adjustment. So really would need to tweak my formula and add a factor for pellet vs. flower.

**EDIT: Also have been using a hop spider for past several months to center hops in pot and possible that is helping for higher hop utilization / which means more IBUs... Possible this could be part of the higher IBUs too.

Talked with the brewer of a small brewery in the area, wondered what he did to adjust alpha content - if anything at all. He suggested me having all of my hops tested before brewing... :roll: Easy for him to say, as his partner in the business tests hops, beer, etc., so he could order in a mini-bale of hops and no problem to take a small sample of hops and have each batch tested by his partner. Of course this is not realistic when purchasing in homebrew hop batch sizes.

One thing I thought was more interesting, for really fresh hops - especially with late flavor additions, his preference is good quality flower. The fresher the better. For bittering - pellets because they tend to do a better job at retaining their Alpha content / bitterness.
Last edited by Scott on 18 Sep 2017, 08:04, edited 1 time in total.


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Re: 2nd Round of IBU Testing Results (6 Beers...)

Post by Streamer » 1 month ago

Well that's an interesting bit of information. Your adjustment spreadsheet seems soundly based, but after testing your results didn't match your expectations - such is the experimental process. Thank you for running this experiment and posting your results! It seems there are a lot of variables - pellet hops vs flower vs hop spider vs primary storage vs secondary storage - my head hurts. Are you writing it off for pellets entirely?
I recently brewed an APA and used the spreadsheet. My bittering hops (pellets) were listed as having 13.1% AA, and using the spreadsheet I adjusted downward to 12.3%. I'm not sure if a 6% mathematical reduction in AA% is significant. At pitching I did taste a big hop bitterness, which is exactly what I wanted. I'll be able to crack a bottle next week sometime, and I'll report back in. That said, I probably won't have the beer tested for actual IBUs, I'll just rely on my own tasting - totally subjective. The next batch of this APA I brew I'll go back to just using the Biabacus, but I've recently built a hop spider and will be using it. This isn't as reliable as your methodology, but it will still be interesting to discover any difference between the two as far as bitterness.
Thanks again
Who controls the past controls the future. Who controls the present controls the past.

George Orwell


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Re: 2nd Round of IBU Testing Results (6 Beers...)

Post by Scott » 1 month ago

Thanks Streamer.

I'm not totally writing it off, but may have to adjust it some and with pellets have it apply a lower percentage. Or perhaps the hop spider made a large impact too. Not certain... :scratch:

Seemed like it was working pretty well until my last batch of testing...beer from spring on, where I was way over on everything. Which is causing me to question everything.

For my last two brews I calculated to see what it said and then adjusted it some.

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