How to adjust ammount of hops according to Alpha Acids

I just recently bought brewing classic styles and the recipes give you the alpha acid of the hops and the ibu's from each hop addition. In the book it says to adjust the amount of hops according to their actual alpha acids, but doesn't tell you the equation. How do you do this? and are there any calculators available?

I've been using the beer recipator The Beer Recipator - Home.

There is a section in the spreadsheet to help you figure out how much you should add and when to get the desired IBU.

hmm, OK but an equation would be idea that way I can figure out how much I need to buy at my LHBS

My method is straight ratio method... I think it is similar to the BU method...

If the recipe calls for 1 oz of hops @ 8% (1 x 8 = 8 BUs) I would substitute 1/2 oz of 16% or 2 oz of 4% (.5 x 16 or 2 x 4 = the same 8 BUs).

Generally, if the AA% of the hops I have is within 10% of the % called for in the recipe, I ignore the difference, as long as my recipe still falls within category guidelines.

NOTE: This only refers to bittering amounts that I use as the 60 min addition. Changing the amount of hops by large amounts will likely change the flavor profile of the finished beer.

(Adding this, because you got a post in while I was typing)

Most likely, your LHBS is only going to sell by the oz. so that won't matter to your buy, unless it forces you up to the next oz.

AA% x (oz. of hops)=AAU(alpha acid units)

10%AA x 2 oz=20 AAU
8%AA x 2.5 oz=20 AAU
5%AA x 4 oz=20 AAU

See where I'm going with this?
This is a good way to adjust hops compared to your recipe.

annasdadhockey said:

AA% x (oz. of hops)=AAU(alpha acid units)

10%AA x 2 oz=20 AAU
8%AA x 2.5 oz=20 AAU
5%AA x 4 oz=20 AAU

See where I'm going with this?
This is a good way to adjust hops compared to your recipe.

Click to expand...

ah sweet thats what I was looking for. Thanks!

No problem.

Here's what I do:

If the recipe tells you to use 8.4% and all you have is 5.7 just divide 5.7 into 8.4 to see how many of the 5.7 you have to use...in this case 1.47 oz.

Same goes the other way...recipe says 5.7 and you have 8.4...8.4 into 5.7 = .67 oz (of the 8.4).

Simple math, really. I think this is more like what you're looking for.

Thanks for the suggestion, I wish it had worked.


calcul financement courtier | simulation pret immobilier | taux credit de france simulation crédit immobilier sera le total du prêt calcul financement courtier | simulation pret immobilier | taux credit de france

bluestarlee said:

Thanks for the suggestion, I wish it had worked.

Click to expand...

You wish what had worked?

Welcome to the forum!!

As mentioned above, adjust the 60 minute addition, and perhaps the 30/15 minute additions. I wouldn't change anything on the 10 minute or lower additions, you are going with aroma/flavor with those and not getting a ton of bitterness. If the recipe wants 1 oz of cascade at flame out it doesn't particularly matter what the AA% of those cascades are.

conpewter said:

As mentioned above, adjust the 60 minute addition, and perhaps the 30/15 minute additions. I wouldn't change anything on the 10 minute or lower additions, you are going with aroma/flavor with those and not getting a ton of bitterness. If the recipe wants 1 oz of cascade at flame out it doesn't particularly matter what the AA% of those cascades are.

Click to expand...

the only hop addition that had a different alpha acid value was the 60 minute addition. It only had 1 alpha acid unit more in the recipe. I am going to just stick with the 1 oz, that way I don't have to buy another ounce for 2.8 grams

Google "rooftop brewing IBU calculator"

chemman14 said:

the only hop addition that had a different alpha acid value was the 60 minute addition. It only had 1 alpha acid unit more in the recipe. I am going to just stick with the 1 oz, that way I don't have to buy another ounce for 2.8 grams

Click to expand...

Sounds like a good plan, I would do the same thing in that situation.