Hope I didn't miss a thread about this, but has anybody listened to the latest Basic Brewing Radio podcast? The topic is the result from the BYO partial boil experiment, comparing hops utilization and color differences between full boil, partial boil, and partial boil with late extract addition in extract and PM brewing.
The results--as tested by a lab--are really surprising. Despite boil gravities of 1.068, 1.127, and 1.077, respectively, the measured IBUs in the fermented beer were roughly the same (about 60, give or take; the BU:GU was the same in all three).
What does this do to our ideas about hops utilization, when you can get, essentially, similar bitterness in 1.100+ wort as in sub-1.070 wort? Tinseth's table, for example, shows 36% less utilization for a 60-minute charge in a 1.120 wort vs. a 1.070 wort.