Hop Ratio between 3 gal & 5 gal boils

[slushy1975]

If a recipe assumes a 3 gal boil size, but you sparge a 5 gallon boil size, by what percentage should you cut your hop amounts to match bitterness?

Because 5 gallons is 40% more than 3 gallons, do you practically cut your hops, in full boils, by 1/2 to acheive the bittering of the more-dense 3 gallon boils?

 

[RiversC174]

Good question, I have oft wondered the same as I am a partial boil brewer... Looking forward to responses.

Joe

 

[RichBrewer]

If a recipe assumes a 3 gal boil size, but you sparge a 5 gallon boil size, by what percentage should you cut your hop amounts to match bitterness?

Because 5 gallons is 40% more than 3 gallons, do you practically cut your hops, in full boils, by 1/2 to acheive the bittering of the more-dense 3 gallon boils?

That is a good question and there has been a recent thread here discussing hop utilization/batch size and brewing programs.
https://www.homebrewtalk.com/showthread.php?t=8569&highlight=utilization
The books I've read say that the lower the boil volume the less utilization you get. The discussion here has been about the gravity of the wort effecting utilization. Higher SG=less utilization.

 

[ajf]

If you are going to drink the concentrated wort without fermenting, then you should scale back the hops roughly in proportion to the two wort sizes.
If, like most of us, you are going to dilute the concentrated wort and ferment it, then you should keep the hopping rate roughly the same as adding water will reduce the concentration of isohumulone (i.e. the bitterness).
I would guess that boiling a concentrated wort is going to result in less isohumulone extraction, and may therefore require an increase in hopping rates to compensate; but I admit this is just a guess, and I have no idea how much (if any) increase would be necessary.
You could always add a hop tea if the reulting beer is underhopped, but it gets difficult to remove excess hops.

-a.

 

[El Pistolero]

If you are going to drink the concentrated wort without fermenting, then you should scale back the hops roughly in proportion to the two wort sizes.
If, like most of us, you are going to dilute the concentrated wort and ferment it, then you should keep the hopping rate roughly the same as adding water will reduce the concentration of isohumulone (i.e. the bitterness).

Respectfully ajf, you're 100% wrong here.

If a recipe assumes a 3 gal boil size, but you sparge a 5 gallon boil size, by what percentage should you cut your hop amounts to match bitterness?

You need to know your OG to get a specific answer, but increasing your boil volume by 2/3 will raise your hop utilization by about that same amount, so you might want to cut your hops in half or so. Run your recipe thru ProMash or Beer Recipator to get accurate numbers.

 

[ajf]

Respectfully ajf, you're 100% wrong here.

Thank you El P, you're 100% right. Inadequate caffeine in the blood supply. I read that he was scaling down a full volume recipe, not scaling up.
My bad.

-a.