IBU Test on Beer (to Help Determine Hopping Levels...)

Post #1 made 1 year ago
Decided to send in some samples to the Oregon BrewLab to get a "feel" for how far off my beers' IBUs might or might not be... Was $10 US per sample for the four samples, plus shipping...which seemed pretty reasonable, for R&D purposes. I'll list the 4 brews that I sent in, along with what adjustments were done (if any), estimated IBUs (Tins.) with the BIABacus, along with what IBUs were tested at.

As some of you know, I've been working a bunch over the past couple months to put together spreadsheet to help determine what the present AA value of hops are at, given AA at testing, time, storage temperature & conditions, etc. Remember that all hops' AA drops over time, some more than others. Have made a bunch of progress, and have learned a lot...but have some uncertainties yet. Here is a link to that conversation for those interested. http://biabrewer.info/viewtopic.php?f=150&t=3637" onclick="window.open(this.href);return false; Have expanded greatly above & beyond the spreadsheet at the above link. The updated file is not posted yet, and not sure if/when I will... Want to make sure it is something easy to understand and that it for sure is more help than hindrance. Even if I hit the IBU numbers on exactly, it doesn't mean the adjusted hop AA estimate was exact. (Perhaps the Tinseth formula could be "off" slightly as well...). :scratch:

Sample 1:
Dry Irish Stout
Brew Date: 22 April, 2016
US Goldlings Hop IBUs were NOT Adjusted.
IBU (Tinseth Estimate): 37.1
Actual IBUs Tested: 30 (+/- 1)

Sample 2:
German Inspiration American Pilsner - Santiam Hops
(Great Northwestern Pilsner Malt, Magnum & Santiam Hops)
Brew Date: 7 May, 2016
Hop IBUs on the Santiam's were "guesstimate" adjusted...knowing they seemed low, multiplied IBU by 2/3. Magnum bittering hops not adjusted.
IBU (Tinseth Estimate): 39.0
Actual IBUs Tested: 31 (+/- 1)

Sample 3:
Vienna Lager
Mt. Hood flower hops both for bittering and aroma...
Brew Date: 17 May, 2016
Hop IBUs WERE adjusted per the formula... Finished good but too bitter for the style... 18-30 IBUs are the goal per BCS book.
IBU (Tinseth Estimate): 23.7
Actual IBUs Tested: 31 (+/- 1)

Sample 4:
German Inspiration American Pilsner - Liberty Hops
(Great Northwestern Pilsner Malt, Magnum & Liberty Hops)
Brew Date: 4 July, 2016
Hop IBUs for Liberty & Magnum WERE adjusted per the formula.
IBU (Tinseth Estimate): 39.0
Actual IBUs Tested: 38 (+/- 1)

I brewed the two pilsners which are similar... Just racked the Liberty into keg on Saturday, and that's when I took the samples. Wanted to see if I could make good pilsner with our "local" pilsner malt, and wanted to be able to compare Santiam vs. Liberty hops. Also though...the Santiam I did with an infusion mash, and Liberty got to do a step mash along with mash out. Malt base seems to taste better with the Liberty... Liberty isn't carbonated fully yet but first post fermentation taste I liked the malt base taste better (maybe / probably because of step mash / temps).

The laboratory IBU testing was an interesting exercise. Will likely do it again, but certainly will not be an "all the time" thing...

Adjusting Hop AAs - Efforts & Thoughts:
At this point I think the file is of value and have spent a ton of time on it. BUT...you have to know when the hops were tested, along with storage conditions, etc. Or at least enough to make some "estimated guesses" - plural, and this is still better than just listed the AA on the package. Another thing related that would be interesting - purchase a large enough batch of hops to get them tested to help "prove" the formula (AA Loss Over Time). I'm sure it's not perfect and there will be a range. AA loss will likely vary year-to-year, and finished beer will likely drop IBUs too over time, depending on storage condition.

I was discouraged initially that the Vienna was noticeably a little too hoppy - my formula input data resulted in my overhopping my beer. Likely had some wrong input information... Lab results confirmed this, IBU level at the outer range of the style, but the beer still tastes good...

By the way, I'm not under any illusion that this Formula I've been working with and compiling will be a perfect science... We use IBU estimates in our BIABacus files along with other data, right? Why do we do this? Aren't we trying to be as scientific as possible to closer scale existing recipes and also to be as "Consistent" as possible with our brewing? (It's a good help to guide our brew day as well...). Yes, it's going to be hard to be perfect but we're trying to get it as good as possible. This hop AA loss spreadsheet is meant to get the same result - help provide a more accurate "AA loss over time" estimate, and help guide to a more accurate estimate.
Last edited by Scott on 28 Jul 2016, 12:02, edited 2 times in total.
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Post #2 made 1 year ago
An impressive work of gathering and analyzing data! Experiments like this are what this site is all about, thank you very much for taking the time and sharing your results.


(I'll bet your post brought a tear to Pat's eye)
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Post #3 made 1 year ago
This is an interesting question... I subscribed to this thread and am interested in any new info you find.

After a little searching I found the ASBC method for IBU analysis and it looks like I have the resources to do it so I might be doing a little experimenting myself on my samples!

It would be nice to find a method to determine the alpha acid (humulone, cohumulone and adhumulone) content in the hops themselves prior to addition and monitor that overtime (most closely related to your question) since you wouldn't have to go through the entire process of boiling the hops. Haven't found that yet...

Post #4 made 1 year ago
One quick note...EDITed for Clarity.

The Mt. Hood hops in the Vienna, using the formula I estimated they had dropped from 6.1% at harvest down to 4.5% AA after 10 months and two storage factors...

With adjusting using the BIABacus and it's Tinseth formula...with actual weight amounts used for the hops during my Vienna brew session...to get a beer a beer with IBU of 31 (the IBU measurement actually measured at the lab) I would have had to estimate 6.2% AA for the hops in the BIABacus to have the finished beer IBU wind up where it ended up...which is just higher than that listed on the package.

So if the Tinseth formula is correct within a couple IBU points...and hops were 2015 harvest with AA measured at harvest like the broker told me they were, the AA listed on the package was way too low. (Should've been around 7.6% AA or so at testing last September to have dropped to 6.2%). But then again, the 6.1% AA on the package was almost identical to what was actually in the package for the beer to be as bitter as it was. Broker mentioned that he may "adjust tested AA slightly because of age..." :scratch: That's "clear as mud"...

For sure, the only way to use "the formula" to be accurate, is to get accurate hop information, storage conditions, etc. at the start... Sometimes you can, and sometimes you can't.

Superiorbrew - if you have a lab background and/or have ability to do testing, for sure post what you learn. I feel we're on the cusp of learning some important additional things about hops that aren't commonly known to homebrewers (and many smaller microbreweries without their own labs, honestly).
Last edited by Scott on 29 Jul 2016, 02:18, edited 2 times in total.
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Post #5 made 1 year ago
Yes Scott, good information. Based on what you're saying it makes sense to check the aa value of hops before boil (if I can find a reliable standard procedure) at various hop ages and compare that to what is listed on the package.

Of course translating that to actually bittering (i.e. IBU) is dependent on how long you boil among other things. For instance if you dry hop using hops with even 15% aa you should get little to no contribution to IBUs. If we always assume a 60 minute boil for bittering hops then that makes it simpler. (I'd have to do more research to see what's known about boiling time vs. max bittering conversion).

This is stuff that I hadn't really thought of before so thanks for posting.

Post #6 made 1 year ago
Superiorbrew - the formula I used in my Excel file is a good "guide"... I believe the info / data to be the best information out there - at least for those without actual testing labs. When I have a bit more time can put something together and post it along with more "salient" hop information. But just remember it's only a good guide to help give a better indication for where hops AA% should be - likely not exact, even if our hop storage (and other info) is perfect...

If you are a chemist and have a lab to actually test these things, you could be a huge help!
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Post #7 made 1 year ago
Can't wait to read this thread properly Scott (and your last email!). Laboratory tests - cool :peace:.

Have you any ideas on the harvest date and storage conditions of the hops at various times? Hard info to get but am hoping maybe you got lucky!

Good on you :champ: :thumbs: :clap:
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Post #8 made 1 year ago
Hey PP,

I am making estimates based upon supposed harvest dates, storage conditions, and supposed packaging. This goes into a formula that has estimated AA loss for the different varieties and adjusts based on storage conditions. Also with the above, I am assuming the Tinseth formula used in the BIABacus file is accurate for IBU (within a few %), provided we use an accurate input hop AA%... I think that provided we have semi-accurate knowledge on hop storage conditions and AA test date, and adjust, it will be much more accurate than using the posted AA on the package. After thinking about it more, I plan to do some more tests like this in the future to prove or disprove that these adjustments are of help...

My Vienna Beer:
Hops' actual AA was about the same AA as that printed on the package. Only logical conclusion... In hindsight, I should not have adjusted. Hop Broker was vague when I talked to him again two days ago, but indicated hop AA is when tested after harvest BUT that he "sometimes" makes mental guesses to adjust the printed AA "a little" before he packages hops to sell through homebrew channels... Will be difficult to estimate using his "Fresh Hops" brand if he does this. (He did not mention this the first time I talked with him).

Exbeeriment on brulosophy.com recently where Ray Found brews 2 brews and tests, and they come up short on IBUs vs projected after testing, Ray seems to think its from Tinseth formula inaccuracies. I responded to his post bringing up issue of hops losing their AA over time. Honestly expect that 2/3 to 3/4 of the reason his final beer IBU was off had to do with hops AA being less than that printed on packaging. Ray believes that if hops are given perfect vacuum packed storage conditions, below freezing, that hops will not lose AA. That is incorrect, according to a bunch of info I've come across during research. (Wish he was right, it would make this whole exercise unnecessary).

http://brulosophy.com/2016/07/18/bitter" onclick="window.open(this.href);return false; ... t-results/
Last edited by Scott on 30 Jul 2016, 23:09, edited 1 time in total.
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Post #11 made 1 year ago
Hey MS,

How old? Do you know how long you've had them, and temp you stored them at? My beer fridge's freezer is at -5 deg F. How about before you - who had them and for how long, and at what temp do you think (a guess works)? And what hop variety? What hop crop year, and is the AA test date likely right after harvest? (Do you know where they came from? Could you connect the dots, to a degree?

Give me additional and I can tell you what the "formula" says they have left in AA. (Approximately). Best guess is there should be some value, and just depends on what kind of beer you are trying to make, how much bitterness you need... No idea what else to use them for other than beer... Well actually read that some people make hop tea.

EDIT: Just saw Joshua just made the same hop tea reference... ;)
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Post #13 made 1 year ago
So harvest date and AA tested - approximately 9/1/2011?

Frozen since harvest at -5 deg F - like mine (home freezer)? If they spent time at a hop producer, LHBS, etc., could have been at a higher temp. YVHhops stores at 32 deg F. Others like IndieHops are about 28 deg F. Coolers like a LHBS would have would range between 36 and 44 degrees, approximately. It makes a difference. If I don't know I make an educated guess. Stored since harvest or did you purchase a few months after the fact?
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Post #14 made 1 year ago

I just ran the numbers with your Palisades and think you are okay using them, but would recommend using them sooner rather than later.

Good News: Palisade actually is pretty good for retaining its Alpha Acid. With the standard hop storability test - 6 months @ 20 degrees C / 68 degrees F, it only loses 35% AA in 6 months (retains 65%). That's better than most.

Ran four different scenarios for storage, so you could see the difference. And my questions from above, where I'm asking for details...you can see by examining the below files why details are so important with this.

Files Ending in...:

1 - You got hops immediately after processing and testing, September 1, 2011. They were immediately vacuum packed and stored this entire time at -20 deg C / -4 deg C.

2 - MOST REALISTIC - for most of us, most of the time... Has time at the hop producer, time at a hop broker, time at a local home brew shop, and time in your freezer... So certainly they can have less storage conditions than this, could even have more... Set the file up to have up to four... That's why the effort of doing the separate and additional "storage locations". Frequently temperatures (etc.) are different at the different locations.

3 - Just like #1 from above, but instead of 4 years 11 months, it's actually 5 years 11 months... Resulting loss in AA.

4 - Same as #1, but when you say "freezing"...you mean just 32 degrees Fahrenheit / 0 degrees Celcius. Not my beer freezer temperature...just barely "freezing". Compare this to #1 above, which is the same thing but not as cold. Take a look at the attached files... Big difference in AA remaining. Is this still usable? Yes...probably, but just barely. Use it right away. Almost time for "hop tea", as mentioned by Joshua.

So this is worth what you've paid for it... At least. Hopefully better.

Anyhow, let me know what you think. And please do OPEN the attached files and review how it's laid out. (I'd print them out and put them side-by-side...). Honestly think doing this can be of value, but we have to be able to track the different storage conditions...at least be able to make a reasonable estimate. The way it's in there seems "logical", at least to me...at this point. If we can only track an estimate from the moment we got the hops, and we have no clue on anything before - not when the AA was tested, age of hops, storage temp, etc....we are completely and totally screwed!!! Big Problem!!!!! :shoot: Anyhow, let me know what you think.
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Last edited by Scott on 31 Jul 2016, 12:30, edited 1 time in total.
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IBU Test on Beer (to Help Determine Hopping Levels...)

Post #15 made 1 year ago
From what I have read there are significant challenges in accurately estimating IBUs with any of the formulas and that is highly problematic for late additions.

For example using the biabacus any 0minute additions are said to attribute 0 IBUs but depending on what happens with the wort after flameout will greatly impact this.

For example cube hopped beers, no chill, by this formula should be massively under bittered and out of balance according to tinseth and yet they aren't.

I guess my point is that depending on recipe I wouldn't base the accuracy of measurement of reduction of aa% over time on whether or not it agrees with tinseth and/or lab measurement.

Post #17 made 1 year ago
Thanks for all the work you are doing on BIABrewer, Scott :clap:

Additional information is, I purchased 8 ozs. of Palisade initially from Morebeer on 7/1/2011 (five years ago). Later that year I found those hops as a clearance item and bought 8 pounds.

You are welcome to the hops, if interested.
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Post #18 made 1 year ago
Thanks Mad_Scientist. Very nice of you to say that! :champ:

Contrarian - I've never cubed beer before, so of course haven't cube hopped. Use an immersion chiller because I wanted to have better control on what the hop additions do, different flavors and levels of bitterness imparted at different times into the beer. (Not that no chill and cube wouldn't work perfectly fine...and make good beer, but I feel less in control of what the hops will do for the beer).

No argument that none of of the IBU estimation formulas will be 100% accurate. Supposedly the Tinseth formula is the "most accurate" for those using whole grain... I can work with that until something better is developed.

On the AA Loss Over Time estimate. I didn't come up with the formula. Couldn't find a calculator that put together the different Storage Locations that beer would normally go through so tried to develop something superior. And couldn't find a format that I loved, so spent the time to come up with my own. It's not quite done... But even the % loss estimate is an "estimate" that the hop industry came up with...and likely ranges a little each year, +\-. "If" I have perfect knowledge of the storage conditions of the hops, hopefully it would be fairly accurate...but likely not exact. Had one of my estimates that ended up very close...

Seems like there is a lot of information and knowledge on hops yet to be discovered. Example: "Fresh Hop" (aka "Wet Hop") ales and beers seem to have a huge IBU number, BUT when you drink a Fresh Hop Pale it tastes very smooth - not bitter. So there is a discrepancy there... And I think we get the same with FWH (First Wort Hopping; something Joshua has talked a lot about). I've been doing FWH with most of my Pilsners... So yeah, I think there is probably lots of knowledge about this topic not yet known...we can only do the best we can.

Pat had mentioned the idea of making Hop Tea and using that as a guide for your additions. This may be another good angle to pursue...at least as an "additional step" if you have a lot of a particular hop variety. :scratch: But I do like having laboratory measured scientific numbers, so it's not just a subjective exercise where things are not at all repeatable, etc.
Last edited by Scott on 02 Aug 2016, 08:54, edited 3 times in total.
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Post #19 made 1 year ago
Speaking of Fresh Hop Pale Ale... The Cascade hops on the back of the house are getting close! Probably 2-3 weeks away from harvest. Two bines. Close to half will go in a double batch of Fresh Hop Pale Ale (split into two batches, ferment with different yeast, same besides that). Did this last year and was very lovely! Remainder will be dried and packaged, then used throughout the year for other beer, mostly American Pale Ales. (Sorry, this is a little off topic, but the thought of fresh hop pale is making me thirsty. :drink: )
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IBU Test on Beer (to Help Determine Hopping Levels...)

Post #20 made 1 year ago
Chiller would help with accuracy overboard chill but depends a bit on process as well. Mainly how long after flame out the chiller goes on and then time until it drops below 80C.

Would another approach be to have the hips lab tested after storage to measure aa%? They must do it somehow and you could also run a few side by side experiments with the same starting hops.

Very interesting stuff. Am very interested in the results.

Post #21 made 1 year ago
Hey Contrarian, 80 deg Celcius...that's 176 deg F. For sure within 1 minute I can drop to that temp, using my equipment.

With my chiller and large spoon to stir:
- In 5 Minutes, I can take it from about 216 deg F (102 deg C) to Under 100 deg F (38 deg C).
- With another 5 minutes (10 total), temp is under 70 deg F...maybe closer to 68 deg F (20 deg C). Probably colder than that in the winter...low 60s, and maybe just under 70 in the summer...

Totally agree with the lab testing hops AA idea... Stay Tuned... ;)
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IBU Test on Beer (to Help Determine Hopping Levels...)

Post #22 made 1 year ago
Wow, that's a quick temp drop! I have never bothered with a chiller but that should minimize the conversion of alpha acids from late additions.

From my perspective hops are the real art of brewing as there are so many variables that come into play. Many of which are difficult if not impossible to control or measure but all of the tools available can be helpful and certainly a decent idea of hop degradation over time is another piece of the puzzle.

As an aside I mentioned 80C as in my reading that seems to be the tipping point for conversion of alpha acids into bittering compounds.

Post #23 made 1 year ago
Yeah I thought the 80 C thing had to do with hops stabilizing... I should probably go back and re-research that as well.

My brew kettle has a temperature probe and that first minute it drops incredibly quick! First five minutes are very impressive actually.

If you ever decide to build an immersion chiller I would recommend Max surface area. So either larger diameter tubing than most or longer. I went longer than most of them being advertised...so if basic ones had 25' of tubing, think mine had 50' or maybe even 75'... :scratch: This is obviously a guess but I know I went longer.
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Post #24 made 1 year ago
Scott and Contrarian, to drag up an old link about the essential hop oils and the Temperatures, they Dissolve/Melt,

Check viewtopic.php?f=150&t=2215#p32244

There are many "Melting" Temperatures and "Boil-off" Temperatures.

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