Sometimes I get asked, “What is the difference between alpha and beta acids for hops?”. Well I can tell you, but I must warn you – beer nerd talk is about to get put into full throttle.
When it comes to hops there are two types of enzymes that can be found: 1) Alpha Acids 2) Beta Acids. Now most people are familiar with alpha acids but beta, not so much. So here is the 101 on Alpha and Beta acid chemistry.
If you have been homebrewing for a bit you might have noticed that on packages of hops there is a percentage that is listed. This is normally the Alpha Acid content for the hop. This is composed of: humulone, adhumulone, and cohumulone. And right about now you can forget those…
The alpha acid on a package represents the amount of weight by hop that is composed of alpha acids. Each of those chemicals that are listed above have a different effect on the bitterness of the brew. Not really going to get into it though (in a nutshell: humulone is soft in flavor, adhumulone no one knows what it does, cohumulone is harsh).
When added into the wort while boiling, alpha acids go into solution almost immediately. The bitterness that hops give to beer happens slowly though. The alpha acids are isomerized in the boil and form isomerized alpha acids. That is exactly why bittering hops are added with 60 minutes in the boil or more.
But there is another type of bittering component to the beer. It is the beta acid. Beta acids are composed of: lupulone, colupulone and adlupulone. Beta enzymes really do not create too much bittering to the beer in the same way that alpha acids do.
During the fermentation and storage alpha acids break down slowly, the beta enzymes however create bitterness from oxidation. This affects the long-term storage of beer or lagering a beer.
I believe what I’ve heard is that noble hops are the closest in ratio with alpha and beta having a damn close 1:1 ratio but a lot of brewers prefer a 2:1 ratio which gives a more, “consistent” bitterness over time with age (that’s what I’m told at least).
So I hope that clarifies a bit on the difference between alpha and beta acids in hops!
Leave your comments or questions is the space provided below!
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March 20, 2012 at 2:00 pm
Scientist NERD alert:
The alpha and beta acids are chemical compounds NOT enzymes. Otherwise, nice summary!!
March 20, 2012 at 4:43 pm
Hahah,thanks!
February 17, 2013 at 2:03 pm
Great explanation. thnx
February 18, 2013 at 8:49 am
Sure thing! I’m glad it was helpful.
March 4, 2012 at 11:57 am
Thanks I’m glad it helped out!