FWH is supposed to offer a smoother, more rounded bitterness. No idea how or why or whether that's true. I haven't ever noticed a dif., although I haven't used the technique extensively.
Bitter is bitter to me I can't differentiate between "types" of bitterness yet.
I FWH because I think it is a smoother bitterness. Tons of people on the other side who say the same thing about 60 minute addition. Try it yourself and see which camp you fall in
I believe that a FWH does actually make the bitterness less harsh. When I plug the amount into my calculator it does show an increase in ibu's though. In my recent saison it went from 24 to 26.3 ibu's (1 oz of cascade) in a 90 min boil.
I FWH most of my beers, as I prefer the results. The idea of a 'smoother' bitterness appears to be true to me. The hops steep in the hot (168 degree) wort during the sparge and then are boiled for the entire time,and its supposedly the steeping that makes the bitterness seem smoother.
I did start batch sparging recently, so the results will change a bit since I won't be doing an hour sparge for the hops to steep, but I won't change my technique since it will still work for me.
I ended up putting .75oz of hops in my kettle dry, THEN started the collections, so they ran in on top of the hops sitting there, once I had about 2 gal in my kettle, I stirred the hell out of it for a solid 5 min, then started my burner as I collected the rest (using batch sparge)....so I suppose I will find out, since I usually do the 60 min addition once the boil has started which is when I usually start my timer.
When I first tried FWH it was when we made our first IPA. It not only made for a "seemingly" smoother bitterness but it gave it a hop flavor 20 seconds after you swallowed! Never had a beer do that! We called it Aftershock IPA since we did get a small earthquake during the boil. After getting this secondary hop burst the name was really accurate! We made it again using different hops but the combination really sucked! We ended up dumping it! We really need to try it again using the original type hops to see if we can replicate it.