BeerSmith vs. Ray Daniels

[cperac]

I have problem regarding IBUs calculation.
I'm using BeerSmith to design some brews. To do a double-check I've been doing an Excel worksheet with all the equations Ray Daniels wrote on his book (Designing Great Beers)
The problem is that the IBU calculation in BeerSmith is not coinciding with the equation that Ray Daniels points out (IBUs = (U% * ALPHA% * W_OZ * 7489) / (V_Gal))

I guess the question is: Why do I get different results from BeerSmith when I calculate IBU levels in comparison to Ray Daniels equation?

 

[Wynne-R]

Add ‘em up and divide by two. You realize these are models, right?

 

[MrHopScotch]

Short of sending your beers to a lab, there's no way to be positive what your IBUs will be. Even beersmith has 3 different options for whose equations you use for IBU calculations. They can have a remarkably wide range. I don't know the formulas myself, but one of the other options might line up better with your other calculations.


Sent from my iPhone using Home Brew

 

[TANSTAAFB]

Tinseth vs. Rager models. See http://www.beersmith.com/forum/index.php?topic=7512.0

Beersmith defaults to Tinseth which is the most recent (and empirically validated?) while many older sources are Rager or something else entirely. Not sure which Ray uses.

 

[ktblunden]

Have you tried all three formulas built into Beersmith? I'm sure one of them must come close.