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 Home Brew Forums > AA% conversion
01-04-2010, 04:05 PM   #1
Challenger440
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 AA% conversion

Hey guys
I'm trying to convert a simple hop schedule to hit the desired IBU mark. The hops my LHBS carries are 4.5% and the recipe I am going from used 5.0%.

The recipe adds 1.0 oz Kent Goldings (5.0%) at 60 minutes, for 17.2 IBU. How many ounces of Goldings do I need to add at 60 minutes to hit 17.2 IBU?

Recipe: 1.0oz (5.0%) 60 min = 17.2 IBU
Me: ???oz (4.5%) 60 min = 17.2 IBU

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01-04-2010, 04:11 PM   #2
humann_brewing
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Here is the equation.

IBU = [W(oz)*AA%*U*7489]/V(gal)

IBU = [1.02*0.045*0.25*7489]/5

You can see by this that it doesn't matter much as I have found in brewing, ballpark is close.

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01-04-2010, 04:15 PM   #3
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Quote:
 Originally Posted by humann_brewing Here is the equation. IBU = [W(oz)*AA%*U*7489]/V(gal) the answer would be 1.02 IBU = [1.02*0.045*0.25*7489]/5 You can see by this that it doesn't matter much as I have found in brewing, ballpark is close.
It's monday morning and maybe the answer is obvious, but what does U represent?
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01-04-2010, 04:20 PM   #4
humann_brewing
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Quote:
 Originally Posted by A4J It's monday morning and maybe the answer is obvious, but what does U represent?
U is the time, .25 is for 60 minutes. Here is the article.

http://www.byo.com/stories/recipes/a...lor-techniques
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01-04-2010, 04:27 PM   #5
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Quote:
 Originally Posted by humann_brewing U is the time, .25 is for 60 minutes. Here is the article.http://www.byo.com/stories/recipes/a...lor-techniques
utilization [time]. That's what I figured.

grassy-ass.
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01-04-2010, 04:36 PM   #6
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Divide 5 by 4.5 = 1.1 oz.

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01-04-2010, 05:03 PM   #7
Challenger440
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Thanks guys!

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Keg #1: Oatmeal Stout (WLP004)
Keg #2: Oatmeal Stout (WLP037)
Keg #3: Denny Conn's Bourbon Vanilla Porter
Keg #4: Empty
Bottled: Apfelwein, Scottish 60/-
On Deck: Simtennial Pale Ale