AAU Calculations

[Alphaacid]

I"m having trouble figuring out the math for the AAU's into anything bigger then 5 gallons. The equation: AAU = W(oz) X AA%

If in the recipe I"m given the AAU, how do I rearrange this equation so I can figure out W(oz)?

[jebzter]

W(oz)=AAU/%AA

[Alphaacid]

So that formula only works in 5 gallon batches?


Eg:

7.5AAU of Magnum @ 10%a.a

W(oz) = 7.5/10

W(oz) = 10oz


Can this be scaled up for a 5bbl batch?

[jebzter]

So that formula only works in 5 gallon batches?


Eg:

7.5AAU of Magnum @ 10%a.a

W(oz) = 7.5/10

W(oz) = 10oz


Can this be scaled up for a 5bbl batch?

7.5AAU and you want to get it with a 10%aa hop:
7.5/10=0.75oz

As for scaling, you have to convert AAU to IBU, which factors in the volume of the beer. http://www.howtobrew.com/section1/chapter5-5.html
AAU is good for when you need to figure out how much hops to add to the boil, but you kneed to know your IBU target to get the total AAU you need.
There are many good books on this, the complete joy of homebrewing, the companion book to the complete joy, and designing great beers.

[gbrower]

I use a modified version of Tenseth and Rager equations. I find they work well for big batches. One thing to keep in mind is that your utilization on pilot batches will be a lot less. So that means that you will use about 60%-80% less hops on your big batches, depending on your system.

As far as books I suggest you pick up "Designing Great Beers" by ray daniels.

[BMan1113VR]

For what we use to calculate aau=

(Batch size (in gal) * (1+ Garetz combined adjustment) * Desired IBU) / (Utilization * 74.89)

For us (at least the way we have always done it), Garetz Combined adjustment is:

((SG -0.002) - 1.050))/0.2

hopefully that helps...