SumnerH
Well-Known Member
A lower boil gravity increases utilization of your hops. So a smaller amount of hops in a low gravity boil can give you the same bittering as a larger amount of hops in a higher gravity boil.
*sigh*
Hop utilization is independent of wort gravity. This is something that John Palmer has said that he regrets getting wrong in even the most recent edition of How to Brew, but he's been trying to correct this misunderstanding lately. Listen, for instance, to the March 20 podcast "What is an IBU, Really?" here for his input:
Basic Brewing Radio - 2008
It's something that home brewers have gotten wrong for a long time (because of that, most IBU calculation algorithms get it wrong as well, so most brew software messes it up), but has been well known to commercial brewers for quite a while; the earliest publicly available link I've found is to an American Society of Brewing Chemists abstract from 1989 which reads, in part,
ASBC Journal 1989 - Hop Utilization in the Brewery-An Interbrewery Comparison.The variations are mainly due to differences in equipment but are also influenced by the hop product used. In the range 10.5-13.5° P, no relationship between hop utilization and original gravity was found
Though more recent journals have extended that gravity range significantly.