Hop AA% Testing Theory - Home Brew Forums

Register Now!
Home Brew Forums > Home Brewing Beer > Hops Growing > Hop AA% Testing Theory

Reply
 
Thread Tools
Old 11-02-2012, 06:47 PM   #1
bellmtbbq
Recipes 
 
Aug 2012
Pennington, NJ
Posts: 564
Liked 31 Times on 28 Posts



I don't grow hops, but as an amatuer chemist that follows this board quite a bit, I see a lot of people asking for how to test homegrown hop's alpha acids. It hit me today that one could get a rough estimate from testing the pH of the hop and comparing it to a previously made chart.

If there are acids in the hops, and by nature acids are acidic, and below 7 on the pH scale, you could test the levels of acids. Granted, you couldn't tell the difference between alpha and beta acids.

I might work on this once I get power back in my basement lab if people think this may work. I'd need to compile a chart of different hop varities's pH based on their acid levels.

 
Reply With Quote
Old 11-02-2012, 07:29 PM   #2
45_70sharps
 
45_70sharps's Avatar
Recipes 
 
Sep 2012
Raymond, Washington
Posts: 1,807
Liked 172 Times on 141 Posts


If you find a cheap easy way with decent accuracy, you will have everyone's attention I'll bet.
One problem you might have is getting a baseline since I don't know how accurate the label on any test hops would be since they sample crops, not individual plants when they rate them.
__________________
Let's see if I keep this updated!

On tap
Black Butte clone

In secondary
Pumpkin ale

In primary
Honey wit

Up next.. Firestone Union Jack clone

 
Reply With Quote
Old 11-03-2012, 04:31 AM   #3
theredben
Recipes 
 
Dec 2010
Langley, BC
Posts: 934
Liked 24 Times on 23 Posts


Since the alpha and beta acids are not strong acids, pH of the aqueous solution will not give a simple representation of the acids present. If you want to play around with the pKa's of the alpha- and beta-acids in solution here is a link. I think you will agree that resulting pH will not be any kind of determinant of aa% of the hops used.

http://books.google.ca/books?id=zV9b...mulone&f=false

 
Reply With Quote
Old 11-03-2012, 03:21 PM   #4
bellmtbbq
Recipes 
 
Aug 2012
Pennington, NJ
Posts: 564
Liked 31 Times on 28 Posts


Thanks. What's most interesting about that section is on page 263, there's a very interesting chart on alpha and beta acids solubility. Perhaps that's the way to go about it.

I'd love to produce a really cheap kit or procedure for home hop growers to approximate their AA%.

 
Reply With Quote
Old 11-03-2012, 04:07 PM   #5
theredben
Recipes 
 
Dec 2010
Langley, BC
Posts: 934
Liked 24 Times on 23 Posts


The standard way for homebrewers to approximate the aa of homegrown hops is to make a tea with a known amount of commercial hops, and also one with the same amount of homegrown.
Comparing the strength of the two teas by drinking dilutions of each will let you appoximate the aa of your hops.

 
Reply With Quote
Old 11-03-2012, 11:01 PM   #6
bellmtbbq
Recipes 
 
Aug 2012
Pennington, NJ
Posts: 564
Liked 31 Times on 28 Posts


Quote:
Originally Posted by theredben
The standard way for homebrewers to approximate the aa of homegrown hops is to make a tea with a known amount of commercial hops, and also one with the same amount of homegrown.
Comparing the strength of the two teas by drinking dilutions of each will let you appoximate the aa of your hops.
:facepalm:

I know that's the popular way, I'm talking about something vaguely interesting.
__________________
Check out my blog! Lambic brewday!

Fathom Brewing

-TF

 
Reply With Quote
Old 11-04-2012, 04:33 AM   #7
huntingohio
Recipes 
 
Jan 2011
rural, ohio
Posts: 343
Liked 55 Times on 37 Posts


Excuxe my ignorance on the subject at hand but would the aa% not be the same as the mother plants? They should be genetically identical considering they are from the same plant. I was looking into buying a hop plant cutting from my local homebrew shop and they assured me that it was from the same plants the hops that i buy from them grew out of
__________________
P1 Strawberry bannna melomel
p2 mixed berry cyser
p3 lemon ginger melomel
2 gallon fermenting kit is OTW!!!

 
Reply With Quote
Old 11-04-2012, 04:39 AM   #8
BrewKnurd
 
BrewKnurd's Avatar
Recipes 
 
Mar 2011
Prairieville, LA
Posts: 2,765
Liked 245 Times on 203 Posts


Quote:
Originally Posted by huntingohio
Excuxe my ignorance on the subject at hand but would the aa% not be the same as the mother plants? They should be genetically identical considering they are from the same plant. I was looking into buying a hop plant cutting from my local homebrew shop and they assured me that it was from the same plants the hops that i buy from them grew out of
Growing conditions will impact aa%. I imagine age of hop plant will as well.
__________________
Fake it til you make it.

 
Reply With Quote
Old 11-05-2012, 04:22 AM   #9
GVH_Dan
HBT_LIFETIMESUPPORTER.png
 
GVH_Dan's Avatar
Recipes 
 
May 2009
McFarland (Madison), WI
Posts: 1,102
Liked 255 Times on 183 Posts


Assuming that they are picked at the peak, the aa% would be similar to the "standard" but the growing conditions throughout the year will also impact the final number.

In other words, you can't take a cascade and turn it into an alpha monster through special care but you can take a Magnum and abuse it sufficiently to drop its alpha way down.

 
Reply With Quote
Reply
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
HLT Theory benbradford Kettles, Mash Tuns & Hot Liquor Tanks 3 03-09-2011 10:55 PM
IBU Theory xxHelderxx Recipes/Ingredients 25 02-25-2011 07:08 PM
I've got a theory... blowmax10 General Beer Discussion 1 04-25-2010 02:13 PM
PH testing and Starch Testing. Orfy All Grain & Partial Mash Brewing 18 03-28-2009 05:28 PM
All I have is theory dudasaj Mead Forum 5 08-17-2008 03:07 AM


Forum Jump