Explaining “Hoppiness” with…Chocolate?

by David Nilsen

“Hoppiness” is a bit of an overused word in craft beer. Hops impact multiple sensory characteristics of beer, and the descriptor hoppy could be referring to any or all of them. Let’s look more at what this means.

Taste & Aroma

Hops can provides two major sensory characteristics to beer: bitterness and aroma. Together, these create a third perception we call flavor. When we’re enjoying and describing the flavor of beer (or any other food or drink), we say we’re tasting it, but in reality, we’re both tasting and smelling our beer at the same time.

Here’s how that works:

The taste buds in our mouths only detect five basic tastes: sweet, salty, bitter, sour, and savory, which is sometimes called umami (a couple other possible tastes are being studied, but these are the ones we know for sure). Everything else we perceive as flavor is actually coming from our sense of smell. In contrast to taste, we can distinguish thousands of different aromas with our olfactory system, and we smell those aromas two different ways.

The first channel for smelling is called orthonasal olfaction; this is when we breathe in through our nose, and is what we typically think of when we think about the act of smelling. There is, however a second channel for smell, and it’s called retronasal olfaction. The passageway running from the back of your throat to your nostrils (allowing you to breathe through your nose) allows aroma compounds to reach your olfactory bulb (where smells are processed in the brain) from food and drink that is already in your mouth, and this plays a bigger role than you might think when it comes to enjoying food and drink.

When we have beer or another food or drink in our mouths, aroma compounds travel up that retronasal passage way and hit the olfactory bulb. Then our brain does something weird in order to save us some mental work—it sends a signal back to our mouths to make us believe we’re tasting those aromas. Most of what we perceive as flavor is actually coming from our sense of smell in this way. Taste + aroma = flavor.

So what does this have to do with hoppiness?

Hop Bitterness & Aroma

As I mentioned above, hops can provide bitterness and/or aroma to beer, depending on how they’re used. Let’s look at each.

Bitterness is derived from alpha acids in hops. In their natural state, these alpha acids aren’t very water soluble or very perceptibly bitter. During the boil, these alpha acids are isomerized. Isomerization is the process of a molecular compound being physically reconfigured without adding or removing molecular components. In their new configuration, these iso-alpha acids are notably more water soluble and more perceptibly bitter. Hops added during the boil can add a lot of bitterness to beer.

Aroma (and, by extention, flavor) is derived from essential oils in hops. These oils are quite volatile, so they tend to be lost during the boil. Hops are added at the end of the boil or later in the process to extract these delicate and nuanced aromatic compounds. There are a lot of them, so the range of possible aromas and flavors from hops is pretty amazing. Most of these aromas would fall under fruity, floral, herbal, or otherwise botanical descriptions.

Because bitterness and aroma are derived from completely different compounds in hops, a brewer can use hops to get one or the other or both, depending on how the hops are used in the beer. Add in the fact there are many, many dozens of hop varieties, and the options can get overwhelming. Because of all these variables, there is no one thing that is hoppy. Does hoppy mean bitter? Does it refer to a specific set of aromas, or is any flavor from the hops hoppiness?

Demonstrating Hoppiness in an Unlikely Way

Perhaps the best way to demonstrate the difference between hop bitterness and aroma is with…chocolate.

In a recent episode of Bean to Barstool, we spoke with Eric Parkes of Somerville Chocolate, who makes bean to bar chocolate bars inside Aeronaut Brewing in Somerville, Massachusetts. Eric makes two bars that perfectly demonstrate this different characteristics from hops.

Beer Fermented is a dark chocolate bar made with cacao that was used in Aeronaut Brewing’s Cocoa Sutra Milk Stout. The cacao nibs are added to the beer during primary fermentation, the brewing step that comes right after the boil. The nibs settle into the bottom of the fermenter, which is also where the yeast settles out after fermentation is complete. At the end of fermentation, the Aeronaut brewers, led by Mark Bowers and Filipe Garcia, remove the yeast-covered cacao nibs and return them to Eric, who dries them out and then makes the Beer Fermented bar from them.

These nibs pick up a lot of bitterness from the hops during their time in the beer, even though Cocoa Sutra is not an especially bitter beer. The yeast slurry that settles out also bring hop bitterness with it, amplifying this impact. When you taste Beer Fermented, you’ll notice the green tea-like bitterness from the hops.

By contrast, Hops Dark Milk is made by aging finished bars with hops. The cacao fats in the bar ready absorb aromas just from being in contact with the aromatic hops, and the bars are left with bright fruity and floral notes. But, because this is only aroma, there is no hop bitterness in the Hops Dark Milk bars at all.

By tasting these two chocolate bars side by side, we can see the difference in hop bitterness and hop aroma.