Hop Series Volume 4: Understanding Hop Oils

One of the most complex parts of making a hoppy beer is trying to figure out what to expect from each hop, and how different hops interact with each other.  While this is made easier by using and understanding different hops, there’s some good science to go along with this magic to help us figure out what to expect from certain hop varieties that we haven’t used extensively or made a S.M.A.S.H. with yet.  This week it’s all about hop oils, what flavors to expect from each, and how they can affect your beer.

Reading Hop Oil Compositions

Have you ever looked at a hop description and thought, “Ok, 40% myrcene.  What does that mean to me?” Yeah, me too! The first part of understanding these oils is understanding what it is that you’re looking at when you look at hop oil compositions.

Let’s start at the top.  One of the first things you’ll see is Total Oils, usually measured in milliliters per 100 grams.  This is a standard for measurement, just like in a congress mash where you measure extraction potential of a grain in gravity points per gallon to calculate your potential gravity in a beer.  Let’s use Amarillo hop pellets as our example.  The average range of total hop oils in 100 grams of Amarillo hops are in the range of 1.0 to 2.3 milliliters.  The actual totals oils will differ from year to year and crop to crop, depending on where they’re grown, when they’re picked, how they’re kilned and processed after picking, etcetera, but more often than not, when they’re tested, they’re within 1 - 2.3 mL.

Once you know the Total Oils, the percentage of the different hop oils (also called terpenes) makes a little more sense.  In our Amarillo example, 40 - 50% of that 1 - 2.3 mL of hop oils will be composed of Myrcene. We’ll break down all of the more prominent hop essential oils in just a minute, just bear with me!  As you look at the composition of the oils, and what kind of ranges to expect for each, the potential for flavors gets a little bit clearer, and gives you an idea of what to expect from that variety.  While there are a lot more variables, like biotransformation and what temperatures you add your hops at, this at a glance look can help give you an overview of what you’re working with, as well as help you understand one of our favorite ingredients a bit better.

Hops are an incredible plant that produce tons of flavor and aroma compounds.  These compounds, the same compounds that the hop plants favorite cousin, cannabis, produces, are the driving forces behind hop flavor and aroma.  You can get a good idea of what type of flavors and aromas that you’ll get from late hop and dry hop additions by understanding some of the more prevalent oils in hops. 

While there are over 400 different oils and compounds in hops, as brewers we usually look at the 7 most prominent oils that, more often than not, make up the vast majority of the oil composition of a given variety.  That isn’t to say that all of the rest aren’t there and helping, but that we’re getting the most information from the oils that make up the lion’s share. These main 7 are:

• Myrcene - Resinous and herbaceous.  Myrcene is considered to deliver the smell of fresh hops. While it makes up the majority of the hop oils in many hop varieties, especially American hop varieties, it’s also very volatile and breaks down easily in the boil into other aromatic compounds.  Dry hop additions preserve the most of this pungent monoterpene.
  

• Humulene - Woody, piney and ‘noble’ earthy.  Not as volatile as Myrcene, and therefore more likely to come through when added in the boil.
  

• Caryophyllene - Woody and piney.  Shares the same chemical formula as Humulene, although it’s structured differently and is generally evaluated side by side with it.  When the H/C ratio is 3 to 1 or more, it’s an indication of a hop variety that will be spicy.

• Farnesene - Woody, citrusy and floral.  Farnesene is known for it’s high concentration in Saaz hops and their unique ‘noble’ flavor characteristics.

• Beta-Pinene - Piney and spicy, this terpene is also found in high concentrations in rosemary and pine and spruce trees.

• Linalool - Floral and orange-y, Linalool has an extremely low flavor threshold, meaning that it’s distinct, orange and almost lavender like floral characteristics are evident in very small concentrations.

• Geraniol - Sweet, floral and rose-y, Geraniol is also the precursor to other flavor and aroma compounds that you want in a hoppy beer, including Linalool and beta-citronellol, through biotransformation.

While these aren’t the only flavor and aroma compounds in hops, looking at these percentages and knowing how these compounds act in your beer can give you an idea of what to expect from a new hop variety, especially when comparing them to hops that you’re already familiar with.

The Contrast Theory in Hopping Beer

Ok, so this theory is a work in progress, but have you ever noticed that some hops, like Idaho 7 and Mosaic, perform wonderfully when they’re added as the sole hop in a beer and make a deliciously hop complex product, while other varieties like Cashmere make a beer that’s decidedly ‘flat’ or missing complexity?

If you look at how the hop oils are composed, you’ll notice a little bit more balance in between all of the oils with the first two, while the Ekuanot is blatantly less balanced between all of the acids, even though it has more hop oil per mL.  When I compare hop varieties by oils, what I’m looking for is to create that balance between them.

For example, Mosaic and Citra are a match made in heaven.  We’ve all had Fresh Squeezed and loved every minute of it.  My theory is that to pull out that big, citrus characteristic, you need some contrast with some of the woody, piney and dank oils, which Mosaic provides along with some more citrus characteristics to help push forward brighter flavors.

Again, keep in mind that looking at hop oil composition is like looking at a bird’s eye view of that hops individual potential, and how it plays together with other hop varieties.  Don’t forget to compare oil compositions to the flavor profile given by a variety when you make your choices, and most importantly, brew with as many hops as you can! This will give you the best idea of how they perform in the brewhouse, and the best ways to use them!

Thank you all for reading!  Tell us about your process when choosing hops for your beer in the comments below!  Don’t forget to connect with us on Facebook, Instagram, Twitter and Pinterest to keep up on all of the fun and exciting happenings, new blog articles and videos on BrewChatter TV on YouTube!  Brew On!

References

For the Love of Hops - Stan Hieronymus

Hop Aroma and Hoppy Beer Flavor:  Chemical Backgrounds and Analytical Tools - Nils Rettberg, Martin Biendl and Leif-Alexander Garbe