Homebrewers Association | AHA Forum

General Category => Ingredients => Topic started by: Kirk on October 17, 2010, 08:07:59 PM

Title: measuring home grown hop acid content
Post by: Kirk on October 17, 2010, 08:07:59 PM
anybody know a good way to measure the alpha acid content of home grown hops?  I was thinking it would be making a tea with something like 1 oz hops in 1 qt of water, boiled for 30 minutes, take a ph reading, and voila!  Is it something like that?
Title: Re: measuring home grown hop acid content
Post by: tschmidlin on October 17, 2010, 08:43:49 PM
No.  The ASBC method for measuring alpha acids in hops involves several reagents and a spectrophotometer.

To do it at home your best bet is to make the tea like you mentioned, but compare it to a tea made from hops of known bitterness.  With careful measurements you can probably come pretty close to the actual alpha acid, but I haven't tried it.
Title: Re: measuring home grown hop acid content
Post by: bluesman on October 18, 2010, 12:29:39 AM
No.  The ASBC method for measuring alpha acids in hops involves several reagents and a spectrophotometer.

To do it at home your best bet is to make the tea like you mentioned, but compare it to a tea made from hops of known bitterness.  With careful measurements you can probably come pretty close to the actual alpha acid, but I haven't tried it.

+1

As a homebrewer it's really not worth the investment to have the capability.

I think the best way to measure the hop acids in said hops is to brew a batch of beer and drink it.  ;D
Title: Re: measuring home grown hop acid content
Post by: Kirk on October 19, 2010, 01:37:52 AM
Thanks you guys, you're the greatest.  Yesterday, I made a tea out of my home grown Fuggles, tasting it at 5 minutes, 20 minutes, and 40 minutes of low boil time.  It tasted bitter of course, and slightly earthy.  Not too grassy at all.  Then I did the same thing with Northern Brewer pellets I had in the freezer.  Quite grassy, and I don't think I'll be using them from now on.  It really helped me to "taste sample" the hops in a tea.  I had been using Norhern Brewer a lot for bittering.  But, when I sat back and analyzed the taste of what the hops were doing to my finished beer, I thought "too grassy", and that I had to make a change.  In my last batch, I used Cluster for bittering.  I liked the result much better.  Had I saved some, I would have yesterday also made a Cluster tea.  Next time I will.  Hops are spices, are they not?  It really helps to taste them, in solution, unsweetened, as opposed to relying on someone else's characterization.
Title: Re: measuring home grown hop acid content
Post by: denny on October 19, 2010, 03:47:11 PM
as opposed to relying on someone else's characterization.

This is a point I try to make to every brewer who asks for advice on ingredients.   Of course, it's always valuable to ask other people's opinions, but ultimately you'll have to decide for yourself.
Title: Re: measuring home grown hop acid content
Post by: Kirk on October 22, 2010, 05:15:53 PM
Thanks Denny.  I may start a new topic on this.
Title: Re: measuring home grown hop acid content
Post by: chinaski on October 22, 2010, 05:40:21 PM
My homebrew club, The Green Mountain Mashers, and I did an experimental test of the hop tea methods detailed here:
http://home.netcom.com/~dluzanp/backyard.htm

We tested the methods for three varieties and had 5 or 6 folks independently estimate the %AA of homegrown hops.  We significantly underestimated the true (laboratory measured) %AA in 2 of the 3 varieties.

  I'd like to post the results as a graph but can't figure out how the "insert image" button works.

I'd like to pursue this further sometime in the future as I grow a lot of my own hops.  My latest brews were formulated for the low end of typical commercial hops and adjusted by taste during my brew sessions.

Title: Re: measuring home grown hop acid content
Post by: denny on October 22, 2010, 06:08:03 PM
  I'd like to post the results as a graph but can't figure out how the "insert image" button works.

You can't insert an image directly.  You need to have it hosted somewhere and then you can insert a link.