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Passion for Homebrewing

Now that brewers have literally hundreds of hop varieties from which to choose, crafting a hop-forward beer that tastes new and exotic without resorting to adjuncts has become an elusive target. The new frontier may just be finding the right hop combinations to emulate specific fruits or other culinary flavors not normally associated with beer. In my opinion there is no one better at that game than Dan Shaffer, head brewer at Land Grant Brewing Company. In April Dan joined us on the All Things Beer Podcast – Episode 35: The Columbus Six Pack (American IPAs) – for a fascinating and wide ranging discussion of IPAs and hops. During one segment of that episode, we played a game where I threw out the names of various fruits and Dan suggested a hop or combination of hops that would capture the flavor profile of the fruit in question. I highly recommend anyone with an interest in hops give that episode a listen, but a podcast is not necessarily the most efficient way to archive information, so I’ve decided to translate some of Dan’s wisdom into this blog post. Along the way I’ve sprinkled in some background information and a bit of flavor chemistry. I hope that it will come in handy the next time you want to brew a Mango-Habanero IPA sans fruit, add a hint of orange to your hefeweizen or a lime note to your lager.

Citrus Fruits
The notion that hops add fruity flavors to beer may seem obvious, but before the advent of American hops like Cascade and Centennial in the 1970s and 1980s that was not the case. The flavors of noble hops, like Hallertau, Tettnanger and Saaz, are described with adjectives like elegant, herbal, floral, and spicy. The classic English hops, East Kent Goldings and Fuggle, are said to be earthy, herbal, and woody. The difference between the classic European hops and the upstart American varieties is an increase in the levels of essential oils and a shift in the molecules that are present in those oils. As a general rule, European varieties have more humulene, a molecule that is most closely associated with old world hops (its name has the same Latin root as the hop plant, humulus lupulus). In contrast, New World hop varieties tend to have higher levels of myrcene, a molecule that plays an important role in the smell of thyme, coniferous trees, cannabis, and eucalyptus. Myrcene itself is a hydrocarbon that is highly volatile and therefore difficult to keep in the beer, but its oxidation products have aromas that are fruity, floral, and citrusy. These include linalool (floral, citrusy), nerol (citrus, floral, rose), geraniol (rose, geranium), citral (citrus, lemon, candy like), and limonene (citrus, orange, lemon). These latter compounds are considerably more water soluble than myrcene, which makes them much easier to extract into the finished beer. [1] If you want to dig into the numbers more deeply for specific hop varieties head over to my posts on wet hop ales, starting with Understanding Wet Hop Ales Part 2 – Growing Hops in the Midwest.

As you can see from the above chemistry snippet, the presence of high levels of myrcene most directly translates into the aromas and flavors of citrus fruits. So, let’s see what hop combinations Dan suggests for getting those flavors into your beer:

Orange Juice – Mosaic, Amarillo, Centennial
Orange Rind – Bravo
Grapefruit – Simcoe, Amarillo
Lemon – Lemondrop, Citra, Centennial, Loral Cryo
Lime – Motueka
Notice that two old school American hops, Amarillo and Centennial, make multiple appearances. Both hops are known for having particularly high levels of myrcene. In fact, myrcene makes up a higher fraction of the essential oils in Centennial hops (60-70%) than just about any hop variety, though Citra and Bravo are not too far behind. One might think that to get lemon flavors into your beer you just have to throw in some lemondrop hops, but as Dan notes in the podcast that name is a little misleading as lemondrop imparts flavors more akin to lemon grass than lemon candies. When asked about emulating lime, Dan didn’t hesitate to say that the Moteuka hop from New Zealand is unequivocally the best option. Let’s switch gears to the sensory analysis of various hops using data provided by YCH hops. They provide radar plots of the hop flavors broken down into 14 different aromas, exactly half of them associated with fruits in one way or another. Below I show the plots of just the fruit flavors for three classic old school Pacific Northwest hops – Cascade, Centennial, and Amarillo. All three have pronounced spikes on the citrusy spoke of the plot, while Cascade is citrus forward compared to European hops, Centennial goes even further in that direction. Amarillo doesn’t register as being quite as citrusy as Centennial, but it has less of all the other fruits. In fact, if you are going for citrus and want to minimize other fruit flavors it’s hard to beat Amarillo.

Tropical Fruits
Moving onto tropical fruits – mango, papaya, passionfruit, lychee, guava – the molecular makeup becomes more complex. Many of the same molecules (esters and alcohols) that give citrus fruits their characteristic aromas are still present, but some new molecules have joined the party, including sulfur containing molecules such as thiols and thioesters. The problem is that these sulfur-containing molecules are only present in small amounts in both tropical fruits and hops, where they make up less than 1% of the total oil content. Humans can perceive these molecules at concentrations as low as parts per trillion, which means that your nose is more sensitive to their presence than most laboratory instruments. Unlike alpha acids or myrcene levels you won’t generally find any analysis of thiols or thioester content in the chemical analyses published with each hop variety. For a more in-depth discussion of the challenges of quantifying thiol content in hops check out Stan Hieronymus’ article, “The Complex Case of Thiols” in Craft Beer and Brewing Magazine.

They may only be present in trace amounts, but these molecules can have an outsized impact on your perception of a beer. In minute quantities they add fruity aromas that are suggestive of passionfruit, mango, and sauvignon blanc grapes. Not surprisingly we are going to have to bring in some 21st century hop varieties to get tropical fruit flavors. Since there’s no substitute for brewing experience to find the best routes to tropical fruit forward beers let’s turn Dan’s suggestions for adding a tropical twist to your beer:

Mango – Simcoe, Citra
Passionfruit – Strata, Citra
Pineapple – Sultana, Azacca, Citra
Coconut – Sabro
Guava – Still searching for the right combination
Here we see that Citra is playing the role of tropical booster, much like Centennial and Amarillo did for citrus fruits. Sultana (formerly known as Denali) is notable for being rich in pineapple flavors and Sabro is unique in imparting coconut flavors. In fact, while visiting Idaho I recently picked up a six pack of a Sabro single hop IPA from Sockeye Brewing in Boise, and if you look for it there is undoubtedly a coconut note present. According to Dan paring it with Cashmere produces a mélange of coconut and tangerine flavors. Strata is a newish hop developed collaboratively by Indie Hops and Oregon State University. On the Indie Hops website its flavors are described as passionfruit, melon, strawberry, grapefruit, rock concert cannabis, and dried chilli peppers. That’s quite a combination! When Dan suggested Strata and Citra for passionfruit, he added a caveat, as long as you don’t mind your passionfruit bathed in cannabis.

Before leaving the tropical fruit section let’s take a look at the radar plots for what are arguably the most widely used second generation American hops – Citra, Mosaic, and Simcoe.

These are not wildly different than the plots we saw for the first generation hops (Cascade, Centennial, and Amarillo). Citrus is still the dominant flavor, but tropical and stone fruits play a more important role. The boost in tropical fruits likely signals enhanced levels of sulfur-containing molecules in these hops.

Berries and Stone Fruits
In the radar plots we’ve seen thus far auxiliary fruit flavors like berries, pomme fruits, and melons play second fiddle to the flavors of citrus and tropical fruits. This raises an interesting question, are there hops that can be used to increase the perception of these less intuitive fruits in your beer? To finish up let’s see what suggestions Dan offered up for these most challenging hop-fruit combinations:

Peaches – El Dorado, Azacca
Strawberries – Huell Melon, Strata or alternatively Belma
Blueberries – Mosaic
Black Currants – Brambling Cross
When Mosaic first came out, I thought I could detect blueberry notes in the background. After many years and countless pints of further research I’m inclined to say that was mostly the power of suggestion, at least with my aging olfactory system. In general, I think that berry flavors are going to present themselves as more of a background note than the feature flavor. Stone fruits are a bit easier to emulate, but it’s still challenging to present them in a way that is not overshadowed by citrus and/or tropical fruits.

Let’s finish with the radar plots of three third generation hops, including the two Dan suggests for imparting peach flavors. We do see a little more stone fruit and berry, coupled with a little less citrus, in Azacca and El Dorado, so it makes sense that the peach/apricot flavors would be more to the fore with this combination. Idaho 007 hops turn all the fruit flavors up to 11 (or at least 7) and in my opinion this is a great hop for boosting overall fruit flavor in a beer, especially when used on the hot side as a late addition/whirlpool hop. The fact that Dan didn’t bring up Idaho 007 for any fruit may well be because its flavors are not specific to a single type of fruit, more like a fruit salad (consumed at a rock concert).

Excerpts from: Hop Combinations that Emulate Fruit Flavors – Pat’s Pints (