How can you get 105 IBU from Stone Ruination IPA clone in Zymurgy July/August

Zymurgy
1

Hello,

How can  you get 105 IBU’s from Stone Ruination IPA clone in Zymurgy July/August 2012?

The recipe is:

12.5 lb two row
12 oz 15L
1.75 oz Columbus at -90
1.0 oz Centennial at 0
2.5 oz Centennial dry hop

Brewpal calculates it as: 47 IBU

2

Whose utilization correlation are you using? Tinseth, for example, comes out at ~85 IBU (22% utilization) and Rager at ~125 IBU (32% utilization). Off the top of my head, I don’t remember which Zymurgy uses, and they could just be reporting the value they got from Stone.

3

Also do they specify the %AA on those hops? that varies from farm to farm and year to year. alot of brewers, I beleive, adjust the recipe based on that from batch to batch.

4

I used ProMash at 75% efficiency. For 5 gallons:

12.5 lb two row
12 oz 15L
1.75 oz Columbus, FWH (15% aa)
1.0 oz Centennial at 0
2.5 oz Centennial dry hop

It gave me 105.1 IBUs total, 1.071 SG.

These are all estimates, as you know. Not sure who’s brewing software is the most accurate at calculating bitterness, but we’ve gotten a lot of questions similar to yours, so obviously there’s a lot of variation.

Cheers,

Amahl Turczyn Scheppach

5

Which formula do you use?