Am I doing this hops substitution right?

About to make a pumpkin using some of a recipe I found on here. The original calls for bittering hops 2oz willamette, 1/2oz of cascade. The aroma hops are Mt. Hood - 1oz.

I want to substitute the two bittering hops for Magnum and the Aroma for Sterling (closer to ST pumking).

For aroma, I figure straight up substitution is cool - 1oz of sterling in place of 1oz of mt hood.

For bitteing:

Willamette AA is 4-6% @ 2oz
Cascade AA is 4-7% @ 1/2oz

I figured I'd take averages of 5 and 6 respectively, and running these through a calculator @ 60min and 19% utilization, I get 38 Bittering Units.

So I should figure out how much Magnum will give me 38 Bittering Units right?

Magnum AA is 12-17%. Figuring on 15% average, it would take just under an ounce - .9oz to get 39 Bittering Units.


Am I way off here? Never done this before - usually I follow recipes, not altering them much.

You don't need an IBU calculator and % utilization to do the conversion.
You need HBU (weight of the hops * AA %)
So you have 2 oz Willamette at 5% - 2 * 5 = 10 HBU
You have 1/2 oz Cascade at 6% - 0.5 * 6 = 3 HBU
Add the two together, and you need 13 HBU
Your Magnum is 15%, so you need 13 / 15 oz (0.9 oz) to get the same bittering contribution.

-a.

And you could use an ounce and never notice the difference.

ajf said:

You don't need an IBU calculator and % utilization to do the conversion.
You need HBU (weight of the hops * AA %)
So you have 2 oz Willamette at 5% - 2 * 5 = 10 HBU
You have 1/2 oz Cascade at 6% - 0.5 * 6 = 3 HBU
Add the two together, and you need 13 HBU
Your Magnum is 15%, so you need 13 / 15 oz (0.9 oz) to get the same bittering contribution.

-a.

Click to expand...

So I got the right answer, just with more work? I see. I was just unsure because swapping 2.5oz of hops for less than 1 oz seemed extreme.

Does this sound like a bad idea to you - the substitution in general I mean?

david_42 said:

And you could use an ounce and never notice the difference.

Click to expand...

This was definitely the plan. I'm a round it up kinda guy. Thanks.

I see nothing wrong with the substitution. I'd much rather use a small amount of high AA hops than a large amount of low AA hops for bittering as I cannot taste any difference, and it saves quite a bit of money over the year.

-a.

Good point. Thanks a lot!