Originally Posted by mikesalvo
nice, thanks! At what point should I worry about adjusting the amount? What AAU difference...
mainly bittering additions (early in the boil hop additions). AAUs are translated into IBUs by a function of AA%, time, and specific gravity.
As mentioned, AAUs are easy to caculate by hand; IBUs are not.
So, if you are targeting a specifc IBU #, you can use software to determine what you need based on the AA%/AAU.