Author Topic: IBU Calculations  (Read 1123 times)

Offline Bel Air Brewing

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IBU Calculations
« on: May 16, 2022, 08:11:59 am »
An IBU calculator is used when formulating recipes.

Are these calculators accurate? No matter my target, 20 or 45 IBU’s, my beers trend towards the high side. Almost too bitter for the style.

Brewer’s Friend is the one used.
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Offline dmtaylor

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Re: IBU Calculations
« Reply #1 on: May 16, 2022, 08:20:08 am »
Are you chilling quickly after boil is ended?  How long does it take to chill down the beer to fermentation temperature?

How is your water?  Do you know your mineral content, pH, and alkalinity?

Can you provide an example recipe?
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Offline denny

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Re: IBU Calculations
« Reply #2 on: May 16, 2022, 08:24:56 am »
How do you know they're on the high side? Have you had them analyzed? How do you know what you're detecting is actually IBUs?  See what I'm getting at?

I have use the Grainfather recipe calculator, at least partly because it implements the mIBU formula. I have found that to more accurately reflect the actual bitterness. But until you have your beers analyzed to confirm your perceptions, you're shooting in the dark.
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Offline Bel Air Brewing

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Re: IBU Calculations
« Reply #3 on: May 16, 2022, 09:14:06 am »
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).
« Last Edit: May 16, 2022, 09:28:16 am by Bel Air Brewing »
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Offline denny

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Re: IBU Calculations
« Reply #4 on: May 16, 2022, 09:26:48 am »
You may think you know, but until you have it analyzed you really don't. Maybe it's humulinones rather than actual IBUs.
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Offline Bel Air Brewing

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Re: IBU Calculations
« Reply #5 on: May 16, 2022, 09:36:24 am »
You may think you know, but until you have it analyzed you really don't. Maybe it's humulinones rather than actual IBUs.

A bottle will be shipped to Oregon Brew Lab.

Does the beer need to flat, no CO2? My beer is carbonated now.
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Offline denny

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Re: IBU Calculations
« Reply #6 on: May 16, 2022, 09:59:02 am »
You may think you know, but until you have it analyzed you really don't. Maybe it's humulinones rather than actual IBUs.

A bottle will be shipped to Oregon Brew Lab.

Does the beer need to flat, no CO2? My beer is carbonated now.

That's here in town. Dana is a good friend.  Carbed is fine.
Life begins at 60.....1.060, that is!

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Offline Bel Air Brewing

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Re: IBU Calculations
« Reply #7 on: May 16, 2022, 10:00:22 am »
You may think you know, but until you have it analyzed you really don't. Maybe it's humulinones rather than actual IBUs.

A bottle will be shipped to Oregon Brew Lab.

Does the beer need to flat, no CO2? My beer is carbonated now.

That's here in town. Dana is a good friend.  Carbed is fine.

I'll let them know you sent me!
Winning Gold Medals isn't everything, but it sure is fun!

Offline BrewBama

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IBU Calculations
« Reply #8 on: May 16, 2022, 10:58:24 am »
I’ll just add that the IBU calculators are not correct. They were based on whole cone hops which doesn’t translate directly to pellets. …but it’s what we have so we use them. Several articles have been written describing this.

Also, like water profile calculators, I believe they’re meant to get you in the ballpark. Brew, adjust, rebrew, adjust, rebrew, adjust….  Rarely have I ever brewed a beer and didn’t want to make adjustments.

Offline denny

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Re: IBU Calculations
« Reply #9 on: May 16, 2022, 10:59:18 am »
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.
« Last Edit: May 16, 2022, 11:38:06 am by denny »
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Offline denny

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Re: IBU Calculations
« Reply #10 on: May 16, 2022, 10:59:52 am »
I’ll just add that the IBU calculators are not correct. They were based on whole cone hops which doesn’t translate directly to pellets. …but it’s what we have so we use them. Several articles have been written describing this.

Also, like water profile calculators, I believe they’re meant to get you in the ballpark. Brew, adjust, rebrew, adjust, rebrew, adjust….  Rarely have I ever brewed a beer and didn’t want to make adjustments.

Assuming they all use the same model.
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Offline neuse

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Re: IBU Calculations
« Reply #11 on: May 16, 2022, 11:18:18 am »
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.
For any who are interested, I think Denny is referring to Episode 32 - The IBU Is A Lie (https://www.experimentalbrew.com/podcast/episode-32-ibu-lie). It's worth a listen.

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.

Offline dmtaylor

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Re: IBU Calculations
« Reply #12 on: May 16, 2022, 11:21:14 am »
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).
« Last Edit: May 16, 2022, 11:22:57 am by dmtaylor »
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Offline tommymorris

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IBU Calculations
« Reply #13 on: May 16, 2022, 11:24:14 am »
Are the IBU numbers commercial breweries report accurate? Are they required to report a measured number or do they use the same equations we do and report an estimate (say from Tinseth)?

I compare my bitterness to packaged commercial beer. I am not sure if the numbers from Tinseth are exactly accurate but I think they are consistent and therefore useful.
« Last Edit: May 16, 2022, 12:58:36 pm by tommymorris »

Offline denny

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Re: IBU Calculations
« Reply #14 on: May 16, 2022, 11:39:43 am »
Are the IBU numbers commercial breweries report accurate? Are they required to report a measured number or do they use the same equations we do and report an estimate (say from Tinseth)?

I compare my bitterness to packaged commercial beer. I am not sure if the numbers from Tinseth are exactly accurate but I think they are consistent therefore useful.

In general, I think they're pretty accurate, although there is no requirement. And I agree with your point about consistency.
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The best, sharpest, funniest, weirdest and most knowledgable minds in home brewing contribute on the AHA forum. - Alewyfe

"The whole problem with the world is that fools and fanatics are always so certain of themselves, and wiser people so full of doubts." - Bertrand Russell