IBU calculations inconsistent

Discussion in 'Recipe Editor' started by gozer, Jan 26, 2020.

  1. gozer

    gozer New Member

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    I had a recipe from last year with a magnum addition at FWH. IBUs seemed right at 17. I copied the recipe as a snapshot recently and the SAME hop addition shows as 6. Nothing is different in the two recipes but the IBU calculation. Should I just delete the recipe and start over? no changes seem to have an affect on the bad numbers.
     
  2. Pricelessbrewing

    Pricelessbrewing QA Software Tester
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    We've recently made changes, ie corrections, to how the preboil and postboil gravities are calculated. This directly affects hop utilization and is the likely cause, but if you're able to post a link to the old recipe and current snapshot I can take a look to confirm.
     
  3. gozer

    gozer New Member

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    I found the issue, which is still a bug but not the one I expected: When scaling a recipe (ex: 24L -> 44L), the post boil volume shoots up to 181.6. This is fixed by clicking "calc" after which it goes to 46.5.

    And naturally that incorrect volume was messing with the IBU calculations.
     
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  4. Pricelessbrewing

    Pricelessbrewing QA Software Tester
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    Glad you're able to find it, I've submitted a related ticket for a new approach to boil volumes and will make sure the feature includes consistency with the calc button.
     
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  5. deeJay

    deeJay New Member

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    Hi there, how recent were these changes as I have just copied a recipe from december 8th and IBU's differ from 76.29 to 72.23. Exactly the same recipe and hop additions 100% same recipe. how can that be ?
     
  6. Yooper

    Yooper Administrator
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    Because the new updated calculations change the boil SG slightly, which changes the IBU calculation slightly.
     
  7. Pricelessbrewing

    Pricelessbrewing QA Software Tester
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    The relevant update shipped within the last two weeks. If you compare the boil gravities of the two recipes you should see the difference that is driving the change in IBU.
     
  8. deeJay

    deeJay New Member

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    Got it, thank you.
     

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