Author Topic: IBU Calculations  (Read 1389 times)

Offline pete b

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Re: IBU Calculations
« Reply #15 on: May 16, 2022, 12:25:48 pm »
I use Brewer's Friend and find that it consistently gets me into a range that seems within style expectations but often not exactly what suits my taste. If I brew the same recipe or similar with the same hops and adjust either boil time or amount I can get pretty close to what I had hoped to acheive. I cannot recall the calculator ever seeming way off to my perception.
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Offline HighVoltageMan!

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Re: IBU Calculations
« Reply #16 on: May 16, 2022, 12:27:35 pm »
Hmm.  I see no acid addition.  With so much pilsner malt with very little specialty malt, and somewhat alkaline water source, your mash pH could be quite high about 5.8 or maybe even higher.  This could lead to additional extraction of tannins, phenols, etc.  So then your bitterness might not be so much from IBUs as from some other unwanted extracted thing.  I'd aim for mash pH closer to 5.5-5.6 (as measured at room temperature).
Exactly. Alkaline water will enhance bitterness, but not in a good way. High pH at pitch can lead to higher pH in the finish. Your lager should land at 4.2-4.3 in the finish beer. Higher finish pH will lead to a higher perceived bitterness. The lab report will give you some information and may or may not be useful, but in the end the human palate rules the roost.

Often homebrewers will get the pH right in the mash and never check it at pitch, it almost always rises after sparging even with RO water. Your pitching pH should be 5.1-5.2 ideally. A mash pH of 5.4 is great for mashing, but too high for the pitch.

Edit: The way to test if the pH is too high is to pour a half a glass or so and add 88% lactic or 85% phosphoric acid one drop at a time with a tooth pick. Taste it after each drop and note the bitterness. When you taste the acid you can stop. If the bitterness drops, it's likely your pH is too high in the finished beer.
« Last Edit: May 16, 2022, 12:49:56 pm by HighVoltageMan! »

Offline Richard

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Re: IBU Calculations
« Reply #17 on: May 16, 2022, 12:28:56 pm »
I’ll just add that the IBU calculators are not correct....

Even if they were correct, there is more to bitterness than IBUs, as Dave pointed out. The IBU measurement is nice because it is well-defined and quantitative, but there is a whole lot more to the story than meets the optical absorption device.
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Offline denny

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Re: IBU Calculations
« Reply #18 on: May 16, 2022, 01:38:00 pm »
I’ll just add that the IBU calculators are not correct....

Even if they were correct, there is more to bitterness than IBUs, as Dave pointed out. The IBU measurement is nice because it is well-defined and quantitative, but there is a whole lot more to the story than meets the optical absorption device.

Which is why I mentioned humulinones.  Definitely add the perception of bitterness, but not measureable as IBU even though they come from alpha acids
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Offline Bel Air Brewing

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Re: IBU Calculations
« Reply #19 on: May 16, 2022, 01:47:07 pm »
Hmm.  I see no acid addition.  With so much pilsner malt with very little specialty malt, and somewhat alkaline water source, your mash pH could be quite high about 5.8 or maybe even higher.  This could lead to additional extraction of tannins, phenols, etc.  So then your bitterness might not be so much from IBUs as from some other unwanted extracted thing.  I'd aim for mash pH closer to 5.5-5.6 (as measured at room temperature).
Exactly. Alkaline water will enhance bitterness, but not in a good way. High pH at pitch can lead to higher pH in the finish. Your lager should land at 4.2-4.3 in the finish beer. Higher finish pH will lead to a higher perceived bitterness. The lab report will give you some information and may or may not be useful, but in the end the human palate rules the roost.

Often homebrewers will get the pH right in the mash and never check it at pitch, it almost always rises after sparging even with RO water. Your pitching pH should be 5.1-5.2 ideally. A mash pH of 5.4 is great for mashing, but too high for the pitch.

Edit: The way to test if the pH is too high is to pour a half a glass or so and add 88% lactic or 85% phosphoric acid one drop at a time with a tooth pick. Taste it after each drop and note the bitterness. When you taste the acid you can stop. If the bitterness drops, it's likely your pH is too high in the finished beer.

To be honest, in over 30 years of brewing a pH reading has never been taken. So my beers might be way out in left field for all I know!

Thanks for the info.
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Offline chinaski

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Re: IBU Calculations
« Reply #20 on: May 16, 2022, 02:29:56 pm »
For me, I have calibrated my taste buds to my IBU calculations in my spreadsheet.  I don't care whether an analysis of IBU gets the same number that I calculated or not- I just want my beer to taste the way I prefer.  In addition to that, I use homegrown hops and assume some %aa numbers when I design my recipes so I've learned to trust my taste buds and intuition about my hops.

Offline neuse

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Re: IBU Calculations
« Reply #21 on: May 16, 2022, 02:44:02 pm »
Someone mentioned an experiment we did on the podcast. 15-20 brewers sent in beer theyd brewed for analysis. We found a range of around +/- 50%  on actual IBUs compared to predicted IBU. There are a range of variables that can account for that.  For instance, when we talked to Glenn Tinseth about how he came up with his formula, he said that things like kettle geometry, cooling time, and even the form of the hops could cause results to vary from what he found.

Many, if not most,commercial breweries calculate custom utilization curves based on their real world equipment and practices. Once you have an analysis for a few batches, you can make similar adjustments.
My post didn't go through last time - I'll try again:
For anyone interested, I think the episode Denny was referring to was Episode 32 - The IBU Is A Lie (https://www.experimentalbrew.com/podcast/episode-32-ibu-lie). It's worth a listen.

Offline denny

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Re: IBU Calculations
« Reply #22 on: May 16, 2022, 03:16:53 pm »
For me, I have calibrated my taste buds to my IBU calculations in my spreadsheet.  I don't care whether an analysis of IBU gets the same number that I calculated or not- I just want my beer to taste the way I prefer.  In addition to that, I use homegrown hops and assume some %aa numbers when I design my recipes so I've learned to trust my taste buds and intuition about my hops.

How it tastes and if you like it are all that really matter. Having some sort of IBU reference is helpful for future batches.
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Offline Bel Air Brewing

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Re: IBU Calculations
« Reply #23 on: May 16, 2022, 03:39:04 pm »
For me, I have calibrated my taste buds to my IBU calculations in my spreadsheet.  I don't care whether an analysis of IBU gets the same number that I calculated or not- I just want my beer to taste the way I prefer.  In addition to that, I use homegrown hops and assume some %aa numbers when I design my recipes so I've learned to trust my taste buds and intuition about my hops.

How it tastes and if you like it are all that really matter. Having some sort of IBU reference is helpful for future batches.

True. If you like it, that is all that matters. As this beer was brewed for a competition, I want the judges to like it!
Yes, having a reference is a good thing.
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Offline BrewnWKopperKat

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Re: IBU Calculations
« Reply #24 on: May 16, 2022, 04:01:00 pm »
[...]
For anyone interested, I think the episode Denny was referring to was Episode 32 - The IBU Is A Lie (https://www.experimentalbrew.com/podcast/episode-32-ibu-lie). It's worth a listen.

A couple of additional items from 2017-2018



Offline hopfenundmalz

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Re: IBU Calculations
« Reply #25 on: May 16, 2022, 07:18:47 pm »
Let me answer the above questions, as best I can:

No, never had any beers analyzed. But in a direct comparison of a commercial brewed Helles, mine was substantially higher IBU. My 5D is quite bitter too, certainly on the high end of the scale. More bitter than I recall any of the beers on draft in Mainz and Frankfurt.

Living in North Texas, the elevation is around 700 feet above sea level. We do factor that in.

The beer brewed with the following recipe is quite good. It hits the marks in the BJCP guidelines for a 5D. But the bitterness, while not off-putting, is a tad on the high side based on my personal taste.

Like the above article stated, I guess an adjustment will have to be made, based on my past experience.

Water:
Ca = 40
CaCO3 = 99
Mg = 4
SO4 = 56
Total Hardness = 117
Total Alkalinity = 92

German Pils 5D
10 gallons

10 lbs Weyermann Pilsner
10 lbs Weyermann Floor Malted Bohemian Pilsner
12 oz Weyermann Carafoam

Mash -
Double decoction
Mash in at 139 for 30 minutes
1st decoc 5 minute boil - now 152 for 15 minutes
2nd decoc 5 minute boil - now 162 for 20 minutes
Mash out @ 170

8 gallons mash water, filtered city tap.
9 gallons sparge water, filtered city tap.

Hops - IBU target 39
3.8 oz Tetnanger 5.9% AA (90 minutes)

90 minute boil

The wort is rapidly chilled, getting to 100 F in about 15 minutes, and to 70 in about 45 minutes. But the wort is not run off until a good well defined cold-break is apparent. This may take an hour total time. Sometimes a little longer, summertime. At the end of chilling, the wort is brilliant clear, and the cold-break and all proteins get filtered out in the hop bed (whole cone hops).

Im confussed. 5D is German Pilsner, correct? It should be much more bitter than a Munich Helles.
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Offline Bel Air Brewing

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Re: IBU Calculations
« Reply #26 on: May 16, 2022, 07:43:45 pm »
Let me answer the above questions, as best I can:

No, never had any beers analyzed. But in a direct comparison of a commercial brewed Helles, mine was substantially higher IBU. My 5D is quite bitter too, certainly on the high end of the scale. More bitter than I recall any of the beers on draft in Mainz and Frankfurt.

Living in North Texas, the elevation is around 700 feet above sea level. We do factor that in.

The beer brewed with the following recipe is quite good. It hits the marks in the BJCP guidelines for a 5D. But the bitterness, while not off-putting, is a tad on the high side based on my personal taste.

Like the above article stated, I guess an adjustment will have to be made, based on my past experience.

Water:
Ca = 40
CaCO3 = 99
Mg = 4
SO4 = 56
Total Hardness = 117
Total Alkalinity = 92

German Pils 5D
10 gallons

10 lbs Weyermann Pilsner
10 lbs Weyermann Floor Malted Bohemian Pilsner
12 oz Weyermann Carafoam

Mash -
Double decoction
Mash in at 139 for 30 minutes
1st decoc 5 minute boil - now 152 for 15 minutes
2nd decoc 5 minute boil - now 162 for 20 minutes
Mash out @ 170

8 gallons mash water, filtered city tap.
9 gallons sparge water, filtered city tap.

Hops - IBU target 39
3.8 oz Tetnanger 5.9% AA (90 minutes)

90 minute boil

The wort is rapidly chilled, getting to 100 F in about 15 minutes, and to 70 in about 45 minutes. But the wort is not run off until a good well defined cold-break is apparent. This may take an hour total time. Sometimes a little longer, summertime. At the end of chilling, the wort is brilliant clear, and the cold-break and all proteins get filtered out in the hop bed (whole cone hops).

Im confussed. 5D is German Pilsner, correct? It should be much more bitter than a Munich Helles.

Correct. My Helles is more bitter than the commercial examples, as is my German Pilsner (5D).

The bitterness is not harsh, but it has a long lasting aftertaste. A bit longer than what I care for. Need to address this in the next brew.
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Offline BrewBama

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IBU Calculations
« Reply #27 on: May 17, 2022, 06:04:23 am »
How it tastes and if you like it are all that really matter. Having some sort of IBU reference is helpful for future batches.

I agree. The code could be 1,2,3,…. or A,B,C,… or IBU… as long as there’s a reference so when I taste it I can say this was too/not enough. I’ll take a note so the next time I brew this I’ll use the next higher/lower index.

Though inaccurate, the IBU (which as pointed out above can include other bittering constituencies) is simply a reference number.

I calculate BU/GU and use that to get into the ballpark to begin with and then a data point to make adjustments.
« Last Edit: May 17, 2022, 06:06:16 am by BrewBama »

Offline jeffy

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Re: IBU Calculations
« Reply #28 on: May 17, 2022, 06:27:21 am »
I wonder if the measured IBU level from the test will include all contributors or just the bitterness from hop alpha acid compounds.
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Offline Kevin

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Re: IBU Calculations
« Reply #29 on: May 17, 2022, 06:38:34 am »
For me, I have calibrated my taste buds to my IBU calculations in my spreadsheet.  I don't care whether an analysis of IBU gets the same number that I calculated or not- I just want my beer to taste the way I prefer.  In addition to that, I use homegrown hops and assume some %aa numbers when I design my recipes so I've learned to trust my taste buds and intuition about my hops.

This is the practical answer. If you know your beers, brewed using the calculations available, are more bitter than you desire... reduce the hops and ignore the calculations. Brewing beer, especially at the homebrew level, is as much about art as it is science. Sometimes you have to push one aside in favor of the other to achieve the results you like.
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