I'm brewing Jamil's "Brew Like a Homebrewer" Belgian Dark Strong recipe from Brewing Classic Styles. It calls for enough Hallertauer Hops for 31 IBUS. To get this number on my system and for my batch size, I'll need almost 6oz of 4.0% AAU Hallertauer.
I'd rather not buy 6oz of hops if I don't have to. I'm wondering if this bittering hop can be substituted for something that will get me the alpha I need with a lot less hop. Maybe something like Warrior, CTZ, or something like that?