Alpha Acid content

Marnrfn · 07-25-2011, 10:33 AM

I have 4 different strains of hops growing and would like to figure out the Alpha Acid content of each. Is there a "tester kit" available or do I need to send them to a lab? Also, will the AA change or stay the same - on the same plant, year vs. year?
Thanks in advance!!

**tchuklobrau** · 07-25-2011, 11:55 AM

will change year to year. i suppose you could take to a lab. or just look at the aa range of each variety you have and guess that you are in the middle.

_JP_ · 07-25-2011, 12:15 PM

Yes, (as I understand it) the AA% will change year to year, but not by much. 5-10%?

There are labs you can send them to, but I remember right it's about $30-40, so just about wipes out the savings of growing them yourself.

Another way to check is with "ratiometric titration". Basically, take 1 oz of a known AA (from the store) and make a tea with it. Make a tea with 1oz of the unknown hops (using same amt of water as with the store hops). Taste them and compare. Water down the more bitter one until they equal out. Record how much water was used. Use that to figure out roughly what the AA% is.

SPR-GRN · 07-25-2011, 05:42 PM

I don't want to insult you, so please don't take this post as such (I some times come off sounding like a big ole bag of d0uch3). Even store bought hops will have a varying rang of AA, because of distance travelled, storage conditions etc. My concern with using homegrown hops is that my beer will come out more hoppy/bitter than when I use store bought hops simply because they are fresher and haven't travelled as far, however there is the potential that my hops may not be as potent as store bought because I don't have a farm and my soil conditions are umm far less controlled.
If you are worried about something similar to me (bitterness/hoppyness) then the tea solution is your cheapest bet. Even if you were to send your hops out, the only way for those numbers to be usefull would be if you sent out store bought hops at the same time so you have something to compare them to. However if you are just that much of a beer geek (not an insult, I'm that kind of geek when it comes to motorcycles and cars) and want the figure for you records or to check the progression of AA in your homegrown hops then well the lab option is your best bet. Hope that was somewhat helpful, and I didn't come off sounding like a big ole D-bag. :cheers:

**Randar** · 07-25-2011, 08:19 PM

Quote:

Originally Posted by SPR-GRN

I don't want to insult you, so please don't take this post as such (I some times come off sounding like a big ole bag of d0uch3). Even store bought hops will have a varying rang of AA, because of distance travelled, storage conditions etc. My concern with using homegrown hops is that my beer will come out more hoppy/bitter than when I use store bought hops simply because they are fresher and haven't travelled as far, however there is the potential that my hops may not be as potent as store bought because I don't have a farm and my soil conditions are umm far less controlled.
If you are worried about something similar to me (bitterness/hoppyness) then the tea solution is your cheapest bet. Even if you were to send your hops out, the only way for those numbers to be usefull would be if you sent out store bought hops at the same time so you have something to compare them to. However if you are just that much of a beer geek (not an insult, I'm that kind of geek when it comes to motorcycles and cars) and want the figure for you records or to check the progression of AA in your homegrown hops then well the lab option is your best bet. Hope that was somewhat helpful, and I didn't come off sounding like a big ole D-bag. :cheers:

It's unlikely you will be able to dry them to commercial moisture content levels without some sort of heat and high volumes of air. Even then, you may only get "in the vicinity" (unless you build a dedicated oast).

Until the 3rd or 4th year, aa% will typically be lower than on mature crowns at max potential.

And if you really want to be an EAC about it and use it for bittering and have repeatability, then lab testing is your best bet.

**Randar** · 07-25-2011, 08:21 PM

Oh, and ~$24/sample if you go for testing:

http://www.brewlaboratory.com/

note: I have never used this service, just seen it referenced.

**Retrofit** · 07-25-2011, 10:58 PM

I think your over estimating the variance in alpha and your ability to notice it. Just brew a beer, I guarantee you'll enjoy it.

Marnrfn · 07-26-2011, 11:48 AM

Thanks for the suggestions and advice. I will just guesstimate using a Hops Chart. They haven't failed me yet!

**Randar** · 07-26-2011, 03:49 PM

Quote:

Originally Posted by Marnrfn

Thanks for the suggestions and advice. I will just guesstimate using a Hops Chart. They haven't failed me yet!

If you can weigh them before and after picking you should be able to adjust the estimated aa% content even further. You want to get them to 1/6th of the wet weight, so if you only get to 1/4 or 1/5th, you can further lower your estimated per-weight bittering. And again, start out assuming they will be on the low end of the commercial range per the standard USDA or other published aa% ranges.