I am trying to understand how the IBU is calculated and this is my attempt to do so:
According to Palmer the IBU is AAU * U * 75/ Vrecipe
AAU (alpha acid unit) is the alpha acid (AA%) content multiplied by the weight of the hops. So, if I use 11% Mosaic hops and 0.19 oz of it, then the AAU is 2.09
The U is the utilization factor which is at 0.231 according to Palmer’s chart if I boil hops for 60 mins at 1.053 gravity (see the chart attached).
Vrecipe is the final volume that goes into the fermentor. In my case it is 2.37 gallons.
So, the IBU is (2.09 * 0.231 * 75/ 2.37) which is 15.22.
Now…I’d like to dilute the 2.37 gallons to 3.96 gallons so I need to multiply the IBU of 15.22 by 0.598 (2.37/3.96) which gives 9.1.
So, boiling 0.19 oz of mosaic (11%) hops for 60 mins at 1.053 preboil gravity will give me 9.1 IBU in a 3.96 diluted batch, right?
According to Palmer the IBU is AAU * U * 75/ Vrecipe
AAU (alpha acid unit) is the alpha acid (AA%) content multiplied by the weight of the hops. So, if I use 11% Mosaic hops and 0.19 oz of it, then the AAU is 2.09
The U is the utilization factor which is at 0.231 according to Palmer’s chart if I boil hops for 60 mins at 1.053 gravity (see the chart attached).
Vrecipe is the final volume that goes into the fermentor. In my case it is 2.37 gallons.
So, the IBU is (2.09 * 0.231 * 75/ 2.37) which is 15.22.
Now…I’d like to dilute the 2.37 gallons to 3.96 gallons so I need to multiply the IBU of 15.22 by 0.598 (2.37/3.96) which gives 9.1.
So, boiling 0.19 oz of mosaic (11%) hops for 60 mins at 1.053 preboil gravity will give me 9.1 IBU in a 3.96 diluted batch, right?