Hmm. I wonder how true this is, not doubting the study but ive always been told otherwise. Im interested to see what some of the very experienced brewers think about it
A) IBU calculators are pretty much a crapshoot. At the homebrew scale they're just a tool to help get you in an initial ballpark and then dial in a recipe. None of them are super accurate over a wide range of conditions.
B) IBU's are just a lab value. There is a lot more going on with a beer's bitterness than just IBU's. I've brewed a beer that measured 98 IBU's, but tasted like a smooth 60 IBU beer to me. Then there are other beers in the 40-50 IBU range that taste harsh. IBU's are just one piece of the puzzle. You need to brew to your palate more than a somewhat arbitrary number.
I agree. Even water chemistry can change how you perceive IBUs.
YES. I just recently learned this thanks to Martin Brungard. pH has a powerful influence over perceived hop bitterness.