A homebrew club member is designing an IIPA recipe with hops at 60, 30, 20, 10, 5, and 0 minutes. It made me wonder - what are 30 minute hops for? I never use them and I always figured that at 30 minutes you're blowing out all of the flavor/aroma and not getting the full bittering potential out of them either. Is the bitterness from 30min hops different, or are we better off sticking with 60 and finishing hops?