How to convert hops from a 3 gallon boil recipe to a 5?

Hello! I am going to be brewing an imperial IPA this weekend from a recipe that I found on these forums.

The recipe calls for the following:
36.0 AAU Magnum hops (bittering hop)
15.7 AAU Centennial hops (aroma/finishing hop)
21.0 AAU Centennial hops (Dry hopping)

The recipe calls for a 3 gallon boil, then top it off with water to get to 5.

I typically boil the entire 5 gallons (one reason is that I use tap water).

Through searching the forums I learned that one of the reason a 5 gallon boil is better is you get better hop utilization with a 5 than you do with a 3.

So.. My question is: Is there a formula or a way to scale down a recipe to make up for the higher hop utilization? Is the hop utilization that drastic that it would even need to be scaled down?

As always, thank you for your help!

If you can boil 5 go ahead and do it, you should get better flavor out of the hops and follow the recipe normally without the topoff.

Most brewing software will do that for you when you put in the boil size. Just try to match the IBU's correctly for each addition and you should be fine. I use http://www.brewersfriend.com/ for all my recipes.

It used to be thought that the gravity of the wort impacted hops utilization, but that's been found to be incorrect. I wouldn't adjust any late hops at all (that's about flavor, not hops utilization anyway) and would consider not adjusting the bittering hops unless you're afraid of the possibility of a little too much bittering. I don't think that's likely at all, but if you're worried about it you can decrease the bittering addition (the 60 minute hops) by 20%. Don't change the others.

If it was my beer, I wouldn't adjust it at all.

Thank you all for the info! As usual you have been helpful! I will check out brewers friend!

Divide everything by 3 and then multiply by 5.

I completely agree with Yooper for the reasons she stated.
I would agree with C-Rider if you were scaling up from a 3g batch to 5g, but you aren't.
There may be a very slight difference caused by a 3g boil vs 5g, but IMO that difference (if it exists) would be so small as to be undetectable.

-a.

ajf said:

I completely agree with Yooper for the reasons she stated.
I would agree with C-Rider if you were scaling up from a 3g batch to 5g, but you aren't.
There may be a very slight difference caused by a 3g boil vs 5g, but IMO that difference (if it exists) would be so small as to be undetectable.

-a.

Click to expand...

OOPS, just re-read the OP. My answer is wrong. Sorrry.