Originally Posted by jwalk4
Just a guess, but are you confusing 'AA' (Apparent Attenuation - yeast property) for 'AAU' (Alpha Acid Units - hop property)?
Could be it, but it seems like an annoying way when they could have just listed ABV. How many people know how to calculated the ABV when given the starting gravity (in Plato) and the attenuation? Maybe they are just giving the beer geeks something to feel superior over