« on: March 31, 2014, 10:31:18 AM »
I think there is a lot more to hop bitterness than simply IBUs. Bitterness "quality"(rough vs smooth) is almost as important as "quantity" (IBUs), particularly in hoppy beers. I think there is a lot of variance in perception of these factors as well.
My current house IPA measured 98 IBU in a lab. It uses all flameout/whirlpool hops (no boil additions). When I drink it on its own, it tastes like 60 IBUs, with a smooth bitterness. When I drink it with food it tastes like 100 tongue-clinging IBUs and completely blows out my palate. Same beer, two different perceptions even to the same person.
By calculating FWH as a 20 minute addition, I see it as trying to approximate the bittering quality by adjusting the bittering quantity (IBU) calculation. And it also approximates the additional flavor contribution from the FWH.
The thing is, I'm starting to think that this approximation isn't really doing what I want it to do. Personally, I'm starting to look at each of my hop additions individually instead of my total IBUs for a beer. Since I've moved to adding all my late hops at flameout, that's a fairly simple approach for me.