Confusing BYO hop calculations - Home Brew Forums

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10-15-2005, 12:52 AM   #1
Dude
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Jan 2005
Knob Noster, Missouri
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Anyone else confused in the recipes by the odd way they put AAU instead of ounces?

I was going through an old issue of BYO tonight and found the solution to that riddle:

"AAU (or alpha acid units) are equal to the weight of hops (in ounces) times the alpha acid rating of the hops--AAU = w(oz.) x alpha acids(%). If the recipe calls for X AAU of hops and your hops are rated at Y% alpha acids, you would need X divided by Y ounces of hops. For example, if the recipe specified 12 AAU of hallertau hops and your hops were rated at 4% alpha acids, you would need (12/4=)3 ounces of hops."

Clear as mud?

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10-15-2005, 01:13 AM   #2
david_42

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Oct 2005
Oak Grove, Oregon, USA
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I don't have any problem with the method. About the only time I've concerned myself with this type of calculation is when I want to use a hop that has an alpha number a lot different from the recommended hop. If they call for 12 units and my hop is 11.5%, I toss in an ounce. If my bittering hop is only 7%, I'd use 1 3/4 oz.

Some people want to know exactly what they put in and even go so far as to include the aroma and flavor hops in their bittering calculations. Considering they have no good value for their utilization, I find this compulsiveness amusing.

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10-15-2005, 02:15 AM   #3
Walker
I use secondaries. :p

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Sep 2005
Cary, NC
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Quote:
 Originally Posted by ORRELSE Anyone else confused in the recipes by the odd way they put AAU instead of ounces?
I actually LOVE that way of writing out recipes when it comes to clone recipes. It allows me to know exactly how much bitterness I am supposed to get from that hop no matter what year the crop is.

now, it does make it a PITA to measure things out when you end up needing 1.17 oz, but at least you know you're getting as close to the replication of the original beer as possible.

-walker
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10-15-2005, 03:02 AM   #4
Darth Konvel

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Sep 2005
Columbus, OH
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I prefer the AAU notation myself. I noticed in some recipes they use oz's instead of AAU, or use both notations with the recipe, which I think is rather screwy.
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10-15-2005, 07:13 AM   #5
Orfy
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Sep 2005
Cheshire, England
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You only need that if your formulating recipes.
The oz is fine if folloing a recipe.

I guess they do it to show youw how the worked out the amounts.
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10-17-2005, 04:51 PM   #6
cowain
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Aug 2005
Little Rock, AR
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I prefer the IBU notation. Allows for virtually exact IBU after a messload of calculations.