Do you care more about finding out how hop schedule affects hop bitterness or hop flavor? That will tell you whether to hold mass or IBU constant.

 

JC, your experimental design depends on what it is you want to test. So everyone gets to be right, depending on what they want. I'd like to know the difference in, say, 20 IBUs in a Blonde Ale (likely extract for consistency) added at 60 mins and at 15 mins. Or maybe even hop bursting by putting all my IBUs in at flameout. But that's the test I'd like to run. I just reread the initial post so what I'd do is use a "single wort", doable by using malt extract as the base. I'd do multiple schedules at the same IBU levels. I'd use a neutral yeast, dried. I'd keep my batch size small and do my best to make sure all the variables except the hop schedule the same.

 

Hence keeping IBUs constant: Then you're testing for hop flavor. If you keep quantities constant, you're testing for utilization and by extension bitterness. Dang, I just love experimental design!

 

My opinion would be if you change the quantity you would not be comparing the flavors at different times of addition but comparing different quantities at different times of addition. 2 different exbeeriments. 1 comparing flavor alone and 1 comparing flavor at a set bitterness. For example it would take 5.5 oz of cascade hops to bitter a 1.044 gravity beer to 30 IBU at 5 minutes. Not something you would normally do. But to compare what an oz of cascade added at different times would give you useful info.

 

If I were doing it, I'd keep mass the same. I'd want to analyze how the flavor of an individual hop changes at each point of addition. Loading up on late hops to match IBU is going to amplify hop flavor and aroma. But that might be what you're trying to do.

Last year I did a test to compare the flavors of several different hops. Since AA% varied so much, I split the hops into <7% and >7%. Standard recipe except I doubled the mass of the <7% group. That way the results wouldn't be too swayed by bitterness.

 

I'm pretty sure this has been done not by brulosophy but one of their counterparts I think the guys from (brewing radio)?
They added a set amount of hops to boil 60 min 30min and so on and did a blind taste test to see if people could tell the difference between beers. I don't know how to link it here but Jmac that'll be an interesting listen for you I know it's in one of brulosophy s podcasts.