FWH: IBU calculation question

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Pale Ales and Such

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Hello all,
I’m currently in the process of developing a batch of beer to test out first wort hopping. The problem is: im getting different calculations of the IBU depending on which software I use. From what I can gather, BrewersFriend calculates FWH equivalent to a 20 minute hop boil.

what im trying to do is make a clone of deschutes mirror pond pale ale, and a recipe I found calls for First Wort hopping. This is something I’m intrigued by and would like to try but I’m getting low IBU numbers in Brewersfriend where as other software, im getting much higher numbers. I sort of understand why Brewers Friend calculates FWH the way they do (perceived bitterness vs actual IBU) but to be sure: which app do I use to develop the clone recipe so I can get the expected IBU of what mirror pond is rated at?
If I go with brewersfriend, not only would I have to use a lot more hops (which cost more), im not sure how bitter the ending brew will be, and how close I will get to the deschutes mirror pale ale clone. Any advice on this would be great as FWH is something I really want to try.
Thanks and Cheers
 
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dmtaylor

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The 20-minute thing with FWH is an old homebrewers tale that is blatantly false and misleading. FWH is basically almost identical to full-boil, with a couple 3 or 4 extra IBUs added from the extra soak time. Experiment for yourself but I recommend treating as a full-length boil hop addition maybe with an extra 5 or 10 minutes added on top. Others will disagree which is their right to be wrong.
 

Joshua Hughes

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Hello all,
I’m currently in the process of developing a batch of beer to test out first wort hopping. The problem is: im getting different calculations of the IBU depending on which software I use. From what I can gather, BrewersFriend calculates FWH equivalent to a 20 minute hop boil.

what im trying to do is make a clone of deschutes mirror pond pale ale, and a recipe I found calls for First Wort hopping. This is something I’m intrigued by and would like to try but I’m getting low IBU numbers in Brewersfriend where as other software, im getting much higher numbers. I sort of understand why Brewers Friend calculates FWH the way they do (perceived bitterness vs actual IBU) but to be sure: which app do I use to develop the clone recipe so I can get the expected IBU of what mirror pond is rated at?
If I go with brewersfriend, not only would I have to use a lot more hops (which cost more), im not sure how bitter the ending brew will be, and how close I will get to the deschutes mirror pale ale clone. Any advice on this would be great as FWH is something I really want to try.
Thanks and Cheers
I FWH and Brewers friends does what @dmtaylor says for me, adds 3-4 ibu for 60 minutes In the calculator
 

Miraculix

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The 20-minute thing with FWH is an old homebrewers tale that is blatantly false and misleading. FWH is basically almost identical to full-boil, with a couple 3 or 4 extra IBUs added from the extra soak time. Experiment for yourself but I recommend treating as a full-length boil hop addition maybe with an extra 5 or 10 minutes added on top. Others will disagree which is their right to be wrong.
Brilliant :D

That should be my signature :D
 
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Pale Ales and Such

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The 20-minute thing with FWH is an old homebrewers tale that is blatantly false and misleading. FWH is basically almost identical to full-boil, with a couple 3 or 4 extra IBUs added from the extra soak time. Experiment for yourself but I recommend treating as a full-length boil hop addition maybe with an extra 5 or 10 minutes added on top. Others will disagree which is their right to be wrong.
I originally came to the same conclusion because it makes sense, but what’s concerning is brewersfriend doesn’t calculate FWH like that it seems. And if brewersfriend is using an invalid calculation for that, not sure what else could be wrong with the software…thoughts?
 
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Pale Ales and Such

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And from what I seeing, it appears that if I update brewers friend so it’s the entire boil rather than FWH, it’s about the same. But the other software keeps it around 40 when I change things up…I just don’t know which software to believe for IBUs
 

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Pale Ales and Such

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Just figured it out: brewersfriend has the IBU lower because of the whirlpool step. Whirlpool hop utilization was at 0%. Once I raised that to 10% the softwares basically march at that point. All good now, thank you all for you responses!
 
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DBhomebrew

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FWIW, I calculate my FWH to be equivalent to a 20m addition. I'm no hophead, I don't like bitter bitter bitter. My beers seem balanced to me. When I first tried FWH, calculated as boil length + 10%, I felt the beer was under hopped.

YMMV, of course.
 

Holden Caulfield

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Use a calculator based on the Tinseth model, which many consider the most accurate, model and just use the boil time plus the estimated extra FWH time. My thoughts on why...

Per this great Tinseth model analysis, Impress your Friends - Analyzing the Tinseth Formula, after 60 mins of boil the marginal IBU gain per additional minute begins to drop off considerably. Per the chart below it looks like about 5% more utilization for an additional 20 minutes of boil. In other words, if you have 30 IBUs of bittering hops and boiled them for 80 minutes rather than 60 minutes you would end up with just a couple additional IBUs which is a nit given the accuracy of any of the models. Also, per the Alchemyoverload site, A Modified IBU Calculation (Especially for Late Hopping and Whirlpool Hops), the author determined the Tinseth model tends to overestimate late hop addition IBUs and underestimate early. So the additional IBUs for FWH is between 0 and not very much. Note these are just quick back of the envelope estimates.

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For some more recent data (using pellet hops), this may be of interest:

Nov 1, 2018 - IBUs vs Wort Gravity and Hop Stand Temps (link)
Dr. Chris Hamilton of Hillsdale College in Michigan shares results of his experiments testing the effects of increased wort gravity and different hop stand temperatures on IBU measurements. He also updates us on his research with Clarity Ferm on gluten in beer.​

For example, consider this chart from p 19 of the PDF:

E2: IBU formation at reduced temperature
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Coastalbrew

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There is also a new hop utilization method called the mIBU model. It is used in the Grainfather app and is supposed to be much more accurate for late addition modeling. Might be worth looking into. You can read a blog post about the model here: Maximum IBU (mIBU) in Beer
 
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