Author Topic: Measuring hops via Alpha acids  (Read 2875 times)

Offline Oshez

  • BeerSmith New Brewer
  • *
  • Posts: 2
  • BeerSmith 2 Rocks!
Measuring hops via Alpha acids
« on: September 07, 2018, 08:22:06 AM »
Hey guys, thanks in advance to all,
 I'm new to beer smith and I love it, but I have a q that I couldn't figure out and hoping you guys can share some tips.
my  recipe calls for Alpha acids instead of actual weight, I was wondering if there is and option or a
workaround on how to approach this in Beer smith, cheers to all in advance

link to the recipe below

https://imgur.com/a/z8rmbi5
« Last Edit: September 07, 2018, 08:27:40 AM by Oshez »

Offline Oginme

  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 3115
  • Goats, guitars, and a home brew; Life is good!
    • Longvu LaManchas
Re: Measuring hops via Alpha acids
« Reply #1 on: September 07, 2018, 08:39:14 AM »
The recipe is citing AAU (Alpha Acid Units) for each of the hop additions. The way I would handle this is to make sure that the hops you will be using reflect the %AA on the packaging or lot.  Then, for each hop addition you take the AAU given in the recipe and divide this by the % AA of the hop you have. 

So, for the first addition of Chinook hops the recipe calls for 24 AAU.  If your lot of Chinook contains 12% AA, you take the 24 AAU and divide this by 12 (%AA) and you will need to add 2 ounces of hops.   

Just work this down the line for each of the hop additions.
Recycle your grains, feed them to a goat!

Offline Oshez

  • BeerSmith New Brewer
  • *
  • Posts: 2
  • BeerSmith 2 Rocks!
Re: Measuring hops via Alpha acids
« Reply #2 on: September 07, 2018, 08:42:38 AM »
Hey @Oginme thanks for the quick reply, cheers got it il try it out Appreciate bro :)

Offline EchtBier

  • BeerSmith New Brewer
  • *
  • Posts: 2
  • BeerSmith 2 Rocks!
Re: Measuring hops via Alpha acids
« Reply #3 on: June 19, 2020, 05:25:57 PM »
The recipe is citing AAU (Alpha Acid Units) for each of the hop additions. The way I would handle this is to make sure that the hops you will be using reflect the %AA on the packaging or lot.  Then, for each hop addition you take the AAU given in the recipe and divide this by the % AA of the hop you have. 

So, for the first addition of Chinook hops the recipe calls for 24 AAU.  If your lot of Chinook contains 12% AA, you take the 24 AAU and divide this by 12 (%AA) and you will need to add 2 ounces of hops.   

Just work this down the line for each of the hop additions.

Here?s one for you - which alpha to use?

I noted that the alpha on the YCH pack was very different from their hop lookup tool. From YCH customer service: "I had a chance to touch base with our Smallpack Coordinator for the reasoning behind the AA% discrepancy.  Turns out both numbers are correct; the difference is a result of different testing methods.  The 4.2% was a Mebak test provided by the international originating lab whereas the 2.8% was tested by our lab using the UV method.  We typically state our AA% with the UV method, but the smallpack team initiated their repack from stock that was still tied to the originally provided Mebak alpha."

Hallertauer Mittelfruher.

Offline Oginme

  • BeerSmith Grandmaster Brewer
  • *****
  • Posts: 3115
  • Goats, guitars, and a home brew; Life is good!
    • Longvu LaManchas
Re: Measuring hops via Alpha acids
« Reply #4 on: June 19, 2020, 06:02:11 PM »
It is a good question.  I am not familiar with the specific test method the Mebak test methods list both the spectrographic test method (ASBC) and the HPLC method, so without a specific reference to the test method used, it is really meaningless to compare.  My guess is that you are looking at the comparison of the HPLC (High Pressure Liquid Chromatography) versus a spectrographic method (UV measured at 275 nm) which is most commonly used due to the lesser cost of the equipment and test process.  I think I got the same lot of Hallertauer Mittelfueh marked at 2.8% AA. Since they come from Germany, the testing originally may have been with the HPLC (EBC method), which explains the difference.

My take on it is to use the number you in which have the most confidence.  Since the spectrographic method is the most commonly used, most of the hops you buy will be measured using this test.  Additionally, the IBU models we currently use are based upon testing performed on a spectrophotometer (UV/Vis).

This may be changing as the brewing community and craft brewers in particular are more interested in the specific hop oil breakdown which you can only get via HPLC.  But that will not change the models unless someone bothers to spend the time to redo all the testing needed to produce a modern model based upon modern hopping methods and HPLC analysis of both the hops and the resultant beer.  I have access to both instruments, but actually prefer my taste buds since the UV method is, IMHO, misleading given modern hopping methods as a direct predictor of bitterness.  I have no real comparison to the HPLC method and my bitterness perception.
Recycle your grains, feed them to a goat!

Offline EchtBier

  • BeerSmith New Brewer
  • *
  • Posts: 2
  • BeerSmith 2 Rocks!
Re: Measuring hops via Alpha acids
« Reply #5 on: June 19, 2020, 06:32:07 PM »
Yes, I was leaning toward the lower number. If I relied on the packaging I may have been disappointed in the final product since it may be under hopped. My lesson is if buying hops that originate out of country, verify numbers on the  supplier?s website.

Thanks