8/11/2019 The Science Behind Hops Part 1 – Alpha and Beta Acids

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The Science Behind Hops Part 1  –  Alpha and

Beta Acids

March 12, 2013 by Brian 1 Comment

Hops are a science all their own. Balancing alpha acids, beta acids, and oils all along with aroma,

taste, and overall impression of a beer make choosing the right hop for your beer very tricky.

Doing this well involves knowing a few key terms. Becoming a hop master takes a lot moreinformation than I can give in one post, but this is a great place to start with understanding what

all the information you get with hops really mean. Here is the CBA Science Behind Hops, Part 1:

Alpha and Beta Acids.

Inside every hop a balancing act is going on between alpha and beta acids. These are what give

hops the majority of their bitter flavor, along with many other characteristics that come fromdifferent styles of hops. Both alpha and beta acids are measured by percent by weight of the hop

comprised of that acid.

Alpha Acids

Alpha acids are the most commonly referred to acids when it comes to hops, as these are where

the hops get most of their bittering effect from. There are five main alpha acids, and they are:

1. 

Humulone 

2.  Cohumulone 

3.  Adhumulone 

4. 

Posthumulone 

5.  Prehumulone 

Since each has a unique effect, here is the basics on each alpha acid.

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1. Humulone

This is the primary alpha acid found in the majority of hops. This is where much of the bitterflavor in “hoppy” beers comes from. The humulone alpha acid is also known for it’s anti-

 bacterial, anti-cancer, and antioxidant properties.

Humulone is known for a soft bitter flavor that is far from harsh. Citra hops are a great

example of a hop that has high alpha levels and high humulone levels. Beers with them are bitter,

 but not harsh.

While humulone’s cancer -fighting powers are still are still being studied, studies are also being

done on this alpha acid’s ability to fight pneumonia and bronchitis. This means that maybe that beer you’re drinking is doing you more good than just the enjoyment of a good beer! 

2. Cohumulone

The next alpha acid is cohumulone. The jury is out on whether this alpha acid is good or bad. In

the past this alpha acid was considered less desirable due to the harsh bitterness it helps to impart

in beer. Hop producers actually list this alpha acid out specifically due to this.

Recently, however, with new varieties of hops coming to market, the harshness of this alpha

acid has come into question. With these new varieties that are high in cohumulone, a good,even bitterness has been achieved. Studies are still being done on this to see why this is, but

overall this is generally found in lower percentages.

3. The Rest

 Not a lot is known about the remaining alpha acids, which

are adhumulone, posthumulone, prehumulone. These three add to the overall effect of hops but

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how this is done still is not 100% determined yet. There is a lot of science that goes into

understanding what these alpha acids do, so for a beginner’s guide we can leave it at that. There

are a few good books out there on hops, if this really interests you, I recommend you find oneand get some more information.

 Alpha Acid Wrap-UP

Basically, humulone is a soft bitterness, cohumulone is a harsh bitterness, and the rest are kind ofa mystery. When looking for a hop high in alpha acids, the general rule is high humulone and

low cohumulone.

Beta Acids

The second type of acid found in hops are beta acids. If hops were a band, alpha acids would be

the lead singer, and beta acids would be the 4th guitarist. Most people don’t really know what hedoes, but what he plays is still important to the song.

Beta acids are comprised of three main types. They are:

1.  Lupulone 

2. 

Colupulone 

3. 

Adlupulone 

While alpha acids dissolve into solution almost immediately after being added to the boil,

beta acids break down over time. This is best seen in beer storage and lagering. Beta acids are

generally not talked about on their own, so for this guide we won’t go into each one. Just know

that they break down over time and can change the profile of a beer when it’s aged or lagered. 

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