I originally asked about this on a couple other boards, and didn't get many takers, so I'll throw it out again here:
Does anybody have any idea how Beersmith/Promash calculate %AA (apparent attenuation)?
For instance, my grain bill for JZ's Southern English Brown contains 6 lbs of 2 row, and 2.5 lbs of specialty malts (crystal, carafa, etc). Jam the numbers into Beersmith with my wYeast strain, and it gives me an O.G. and an F.G., with the F.G looking like it's calculated from the Average AA for that yeast strain in the Beersmith database. (I am using 1469VSS, and I copied the 1968 specs into the Beersmith database for it)
Now, if I use 8.5 lbs of 2 row in Beersmith, and compare with an equal O.G. of crystal 80l, I get almost the same AA (1.6% difference, the wrong way AFAIAC)).
For example:
8.5lbs UK 2 row and wYeast 1968 gives an OG/FG of 1.041/1.013
8.75lbs of crystal 80L and wYeast 1968 gives an of 1.041/1.012
Beersmith says a beer made of 80l crystal should attenuate better than a beer made of 2-row. Shouldn't there be a bigger difference than that in F.G.?
In JZ's original recipe, aren't 2.5 lbs of specialty malts pretty much non-fermentable (crystals, chocolate, etc). Shouldn't Beersmith calculate a significantly higher F.G. for the 2-row/specialty malt SEB recipe?
I look at the recipe I brewed (from JZ's book), with it's target AA, taste my sample, which I measured at 7% lower AA than the target and Beersmith calculation, find it's pretty good (that's the best I can do descriptively), and wonder, are the given AA numbers right?
Does anybody have any idea how Beersmith/Promash calculate %AA (apparent attenuation)?
For instance, my grain bill for JZ's Southern English Brown contains 6 lbs of 2 row, and 2.5 lbs of specialty malts (crystal, carafa, etc). Jam the numbers into Beersmith with my wYeast strain, and it gives me an O.G. and an F.G., with the F.G looking like it's calculated from the Average AA for that yeast strain in the Beersmith database. (I am using 1469VSS, and I copied the 1968 specs into the Beersmith database for it)
Now, if I use 8.5 lbs of 2 row in Beersmith, and compare with an equal O.G. of crystal 80l, I get almost the same AA (1.6% difference, the wrong way AFAIAC)).
For example:
8.5lbs UK 2 row and wYeast 1968 gives an OG/FG of 1.041/1.013
8.75lbs of crystal 80L and wYeast 1968 gives an of 1.041/1.012
Beersmith says a beer made of 80l crystal should attenuate better than a beer made of 2-row. Shouldn't there be a bigger difference than that in F.G.?
In JZ's original recipe, aren't 2.5 lbs of specialty malts pretty much non-fermentable (crystals, chocolate, etc). Shouldn't Beersmith calculate a significantly higher F.G. for the 2-row/specialty malt SEB recipe?
I look at the recipe I brewed (from JZ's book), with it's target AA, taste my sample, which I measured at 7% lower AA than the target and Beersmith calculation, find it's pretty good (that's the best I can do descriptively), and wonder, are the given AA numbers right?