Hops AAU equasion question - Home Brew Forums

 Home Brew Forums > Hops AAU equasion question

09-27-2007, 12:16 PM   #1
Recipes

Jan 2007
Posts: 86

I have a recipe that I will be brewing this morning. The recipe calls for Hallertau Pellets 4.5% alpha acids. When I went to the local home brew shop they only had Hallertau 4.2% Alpha acid.

My question is how do I do the math to figure out how to add more/less hops to my brew? Thanks for the help.
__________________
I would rather be tried by twelve than carried by six.

09-27-2007, 12:45 PM   #2
Khirsah17
Recipes

Jul 2006
Columbus, OH
Posts: 164
Liked 1 Times on 1 Posts

The equation for calculating AAU is:

AAU = AA (%) X Hops (oz)

So in your case, if the recipe calls for 3 oz of Hallertau at 4.5% AA,

AAU = 4.5 X 3 = 13.5 AAU

So you can use that to solve what the amount of hops you need at 4.2% to still get you the same AAUs.

Hope that helps!

09-27-2007, 02:33 PM   #3
TexLaw
Here's Lookin' Atcha!

Recipes

Sep 2007
Houston, Texas
Posts: 3,670
Liked 28 Times on 26 Posts

Just to finish that up:

Hops (oz) = AAU / AA (%)

So, Hops (oz) = 4.5/4.2= 1.07

So, you need 1.07 oz of 4.2% AA hops for every 1 oz of 4.5% hops in the recipe. In other words, you need a little more

TL

09-27-2007, 02:50 PM   #4
FSR402

Recipes

May 2007
Jenison, MI
Posts: 2,826
Liked 26 Times on 19 Posts

Quote:
 Originally Posted by TexLaw Just to finish that up: Hops (oz) = AAU / AA (%) So, Hops (oz) = 4.5/4.2= 1.07 So, you need 1.07 oz of 4.2% AA hops for every 1 oz of 4.5% hops in the recipe. In other words, you need a little more TL
In other words, not enough more to bother figuring it out.
__________________
TWO FISTED BREWING CO.

Quote:
 Originally Posted by mr_cad Its nice when you and your friends have comparable equipment.
Quote:
 Originally Posted by Walker-san some people will tap anything that has a hole.

09-27-2007, 02:51 PM   #5
TexLaw
Here's Lookin' Atcha!

Recipes

Sep 2007
Houston, Texas
Posts: 3,670
Liked 28 Times on 26 Posts

Quote:
 Originally Posted by FSR402 In other words, not enough more to bother figuring it out.
Yep. But, I miss doing arithmetic sometimes.

TL

09-27-2007, 03:03 PM   #6
Dude
Will work for beer

Recipes

Jan 2005
Knob Noster, Missouri
Posts: 8,770
Liked 89 Times on 70 Posts

I brought this up a LONG time ago....

...if nothing else, my first post has another explanation for the equation. The answers you've gotten so far suffice though. Just offering more.

__________________
On Tap: Lake Walk Pale Ale -- Eternity (Raspberry Stout) -- Nutrocker -- Donnybrook Dark
Primary: Lake Walk Pale Ale
Secondary: Summit IPA
Up Next: Smoked Porter -- Pub Ale -- Watermelon Wheat
Planning:
Gone But Not Forgotten:

www.IronOrrBrewery.com

09-27-2007, 04:36 PM   #7
malkore

Recipes

Jun 2007
Posts: 6,922
Liked 37 Times on 35 Posts

use two extra hop pellets
__________________
Malkore
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10

09-27-2007, 11:14 PM   #8
boo boo
Recipes

Jun 2005
Hearts's Delight, Newfoundland
Posts: 4,165
Liked 36 Times on 31 Posts

1 oz of any hop at a AA rating is the AAU of that hop.

For instance 1 oz of 7.1 AA cascade would be 7.1 AAU's
1 oz of 6.3 AA cascade would be 6.3 AAU's

If you needed 7.1% AAU's of cascade and had 6.3% then you divide 7.1 by 6.3 to get 1.13 oz.

And if you had 7.1 and needed 6.3 then divide 6.3 by 7.1 to get .89 oz.
__________________
How do you BBQ an elephant....first you get your elephant....

09-28-2007, 01:30 AM   #9
Recipes

Jan 2007
Posts: 86

Thanks for all of the help. I successfully hopped da brew.
__________________
I would rather be tried by twelve than carried by six.