attenuation

Iliff Avenue Brewhouse

Iliff Avenue Brewhouse

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I get two different attenuation figures using the recipe builder and the abv calc tool. The recipe builder doesn't seem to be calculating attenuation correctly. When I enter a custom value of 83% it is actually calculating for 90%.

OG of 1.081 and FG of 1.008
recipe builder shows - 83% aa (not correct)
abv calc shows - 90% aa
 
We're checking into this. Do you happen to be able to show a screenshot of both, so we can see what you're looking at?
 
upload_2019-5-20_8-53-19.png
 
Great- thanks. First, can you check "late addition" with the sugar, as it's not mashed. It might not change it correctly, but it might.
 
Checking/unchecking that box only changes my IBU figures.

Only seems to be affecting this recipe...
 
Last edited:
Hmmmm- can you give me the link to the recipe and the calc page, and I'll take a look?
 
If I delete the sugar and re add it custom, it seems to correct it. Unfortunately, it won't save the changes now.
 
Yooper said:
It won't save the new custom attenuation?
Click to expand...

It won't save the recipe. If I go to edit it again, the custom sugar addition is gone with the default one back.

Just for reference the default entry for cane sugar gives me a FG of 1.007. When I delete it and put in a custom field with the same figures, the FG is 1.010 which is correct considering the entry for attenuation.
 
Iliff Avenue Brewhouse said:
It won't save the recipe. If I go to edit it again, the custom sugar addition is gone with the default one back.

Just for reference the default entry for cane sugar gives me a FG of 1.007. When I delete it and put in a custom field with the same figures, the FG is 1.010 which is correct considering the entry for attenuation.
Click to expand...

Can you show a couple of screenshots, so I can try to recreate the issue (so we can fix it!)?
 
When I view the recipe:
upload_2019-5-28_7-34-49.png


When I edit the recipe:
upload_2019-5-28_7-38-30.png


Attenuation is set to 85% for both scenarios.
 

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Hi, I have been reading these comments, and I didn't find an answer on my issue. I am wondering if the calculations of FG in the recipe builder are correct based on attenuation of the yeast. I have put 75% attenuation for a certain yeast. The OG is 1.080. According to my calculation, based on an attenuation of 75% , FG should 1.020 but the recipe builder calculated 1.016? Is there something I miss?
 
STRU said:
Hi, I have been reading these comments, and I didn't find an answer on my issue. I am wondering if the calculations of FG in the recipe builder are correct based on attenuation of the yeast. I have put 75% attenuation for a certain yeast. The OG is 1.080. According to my calculation, based on an attenuation of 75% , FG should 1.020 but the recipe builder calculated 1.016? Is there something I miss?
Click to expand...

Hmmm something else must be going on. Can you give me a link to the recipe?
 
Oh, it has sugar in it! I should have thought of that right away. Since simple sugars are 100% fermentable, the attenuation for added sugars aren’t calculated with the yeast attenuation. That means that the sugar will ferment out completely, while the grains will still give you the 75% average.
 
I've got a similar issue (no sugar, no DME, just standard base and kilned malts).
See here: https://www.brewersfriend.com/homebrew/recipe/edit/1124583

OG = 1.055
Attenuation = 76%

EXPECTED FG: 1.013
ACTUAL FG calculated by software: 1.016

it seems the software calculates here a 70-71% attenuation instead of the requested 76% atenuation.
changing the yeast strain or the pitch rate makes no difference

it should be simple math: what am I missing here?
 
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