So here's the recipe that got me going on whirlpool hop utilization: https://www.brewersfriend.com/homebrew/recipe/view/656025/house-ipa-1 I wanted to check the finished beer against a known quantity and Sierra Nevada Torpedo IPA is in the same range so I picked up a bomber. Torpedo is a go-to for me so it's not a hardship to have one around to drink. After a very un-scientific comparison regimen I'm able to report that my 20 minute whirlpool at 180 probably did not deliver the 4% utilization that I guessed at. Even with flameout hops (in fact, all the hops) left in for whirlpoool and a substantial addition at 180 degrees, the projected 65 IBUs didn't seem quite as hoppy as the Torpedo. And this is a beer that's a full percentage point lower in ABV than the Torpedo. I estimate the IBUs for my batch at around 60 rather than 65, maybe a little lower. It's noticeably, but not substantially less bitter so it's not too far over the threshold of perceptible difference. Fun Fact: I have 2 kegs of a coincidentally nearly dead-on Torpedo clone. Even though the malt bill is different and the hops are different, the flavor, color and aroma of the 2 beers is astoundingly, confusingly similar. I'm not certain that it would pass a triangle test, but seriously, it would stand a chance.