I have the BYO Hop Lover`s Guide and have brewed up a couple of recipes. I noticed today that Ruination IPA recipe calls for a boil of 11 L diluted in the primary to 19 L. They claim IBUs of 100+ finished product, but obviously this is impossible. Even if a 100 were achieved at boil, it is then watered down to 50%, so the theoretical upper limit should be 50 IBUs, right?
This disturbed me out, so I started going through and running some of the math on all grain versions (to avoid the difficulty calculating changing gravity with late addition extract versions). Pretty much all of them came out way under the IBUs they are supposed to have. I am totally open to the fact that I may be doing something wrong, but I ran it through using the utilization formula in the guide, and then double checked with a calculator online (www. brew65.com).
Here's some examples:
Flying Dog Gonzo Clone:
9.7 g @ 16%AA x 90 min
30g @ 9%AA x 60 min
30g @ 9%AA x 30 min
By hand I got: 54.55 IBU for a full 19 l boil
The online calculator gave:
Tinseth: 53. 38
Rager: 49.05
This is a big difference!
The Yeti Clone is similar:
31g @ 13%AA x 60 min
16 g @ 13%AA x 30 min
14g @ 10.5%AA x 15 min
14g @10.5%AA x 5 min
This yields (by hand) 56.69 IBU
Online:
Tinseth: 56.55
Rager: 51.88
All are a far cry from the 75 IBUs the recipe claims.
I am really perplexed. Am I missing something? Help!
Jason
This disturbed me out, so I started going through and running some of the math on all grain versions (to avoid the difficulty calculating changing gravity with late addition extract versions). Pretty much all of them came out way under the IBUs they are supposed to have. I am totally open to the fact that I may be doing something wrong, but I ran it through using the utilization formula in the guide, and then double checked with a calculator online (www. brew65.com).
Here's some examples:
Flying Dog Gonzo Clone:
9.7 g @ 16%AA x 90 min
30g @ 9%AA x 60 min
30g @ 9%AA x 30 min
By hand I got: 54.55 IBU for a full 19 l boil
The online calculator gave:
Tinseth: 53. 38
Rager: 49.05
This is a big difference!
The Yeti Clone is similar:
31g @ 13%AA x 60 min
16 g @ 13%AA x 30 min
14g @ 10.5%AA x 15 min
14g @10.5%AA x 5 min
This yields (by hand) 56.69 IBU
Online:
Tinseth: 56.55
Rager: 51.88
All are a far cry from the 75 IBUs the recipe claims.
I am really perplexed. Am I missing something? Help!
Jason