Testing Hop Alpha Acids

[darylM]

I know that when calculating IBU or AAU the alpha acid content is critical. My question is if you grow your own hops, how do you test the alpha acid content?

[Mad Scientist]

The best I could recommend is to contact freshops and ask them, and follow the method. I'll bet that it is determined by liquid chromatography.

BTW, welcome to the board. I used to live in Boerne, shame I still do not.

[corkybstewart]

It's probably difficult/expensive. For bittering use the "average" AA for the strain you're using, or use them for dryhopping or late additions so that they don't have much influence on bittering.

[darylM]

Originally posted by corkybstewart
It's probably difficult/expensive. For bittering use the "average" AA for the strain you're using, or use them for dryhopping or late additions so that they don't have much influence on bittering.

I was thinking of assuming the center of the range and figure it from there. I did email freshops to get thier opinion. I did some research on the Internet and it does sound expensive.

[Mad Scientist]

What is the analytical method? I can figure the $$$ out for you very quickly, I think.

[darylM]

Originally posted by Boerne Brew
What is the analytical method? I can figure the $$$ out for you very quickly, I think.

hplc

[Carl Spakler]

I went to a link on the BYO site and found a calculation for IBU, I tried to run the numbers for my DIPA. It came out WAAAAYYY high...like in the 400+ range? :confused:

[Mad Scientist]

Originally posted by darylM
hplc

NO HPLC is high performance liquid chromatography.

That is the instrument. Like the computer you are using.

The analytical method is the set of instructions that the HPLC will use to determine the alpha acid content of the hop sample you send in--much the way your computer will use a software package to do generate data or output as you desire.

[darylM]

Originally posted by Boerne Brew
NO HPLC is high performance liquid chromatography.

That is the instrument. Like the computer you are using.

The analytical method is the set of instructions that the HPLC will use to determine the alpha acid content of the hop sample you send in--much the way your computer will use a software package to do generate data or output as you desire.

Point taken, The short answer then is more looking is necessary

I could always go the engineer approach and use known values that can be off by 10% or so and not change the bittering too much.

[Mad Scientist]

I'l bet that using middle of the road values will be okay. though I might err on the low side since TX is considerably hotter than the pacific northwest. maybe another texas hop grower can comment. Corky may also have wisdom to lend on this subject, since he grows in Carlsbad NM.

[HogieWan]

I've heard most homegrown hops are lower in their AA% than commercial grown. I plan to use the lowest number in the range, and adjust the recipes from there.

[dparsons]

I would go with the "brew a batch and see how it turns out" method. 2nd time around you'll know whether to add more or less.

[kujo]

My brewing partner decided to grow his own hops this year, and he purposely picked varieties that would only be useful in the last ~10 minutes of the boil specifically because it's too expensive/hard to determine the alphas on hops. If anyone finds a way to do this at home, that'd be really cool!