Phenotype, genotype, genetic crosses, controlled pollination. These might not be the first terms that come to mind when browsing through the beer store, but the genetic background of the hop varieties used in your favorite beers could be a useful tool when trying to pick up a six-pack for the weekend. Ever since hops were first used in beer making, brewers have been combining different varieties and exploring new ways to impart hop flavors and aromas into the finished product. To keep up with this voracious appetite for experimentation, hop farmers have put down their shovels and put on lab coats, using genetics to introduce new flavors and aromas to the brewer’s palette.
Much like the grapes used to make wine, hops come in a multitude of varieties, all of which impart their own unique aromas, flavors, and bitterness. Unlike wine grapes, however, most hop varieties are relative newcomers to the scene. The majority of hops you find in your average American pale ale are actually intentionally crossbred hybrids of older lineages. These ancestors of today’s hops are the source of the subtle bitterness and fragrant, floral aromas found in traditional German and English beer styles. Pilsners and bocks are hopped gently with “noble hops” named after the German regions where they are grown: Tettnang, Saaz, Spalt, and Hallertau. English bitters and ales display the subtle bitterness of hops like Fuggles and Goldings, varieties that were first cultivated in the English countryside in the 18th and 19th centuries.
Experimentation with crossbreeding, however, didn’t start with combining these traditional European cultivars. It began in the early 1900s when E.S. Salmon, a professor at Wye College in England, crossbred a wild seedling transplanted from a small town in Manitoba with an unknown variety that grew in England. This breeding gave rise to Bullion and Brewer’s Gold, the genetic foundations for a large percentage of the hop varieties used today.
Bringing a new hop variety to market isn’t quite as easy as swapping pollen from one plant to another, however. The first step is to identify which traits to aim for in the new variety. While the exciting things like aroma and flavor are a major consideration, the yield and resistance to disease and pests is even more important. Doug Donelan, head of the New Zealand hop grower cooperative NZ Hops, sums it up nicely: “Not much good creating the world’s best aroma hop if you can’t grow it.”
Once the desired traits are identified, the next step is finding out which hops will produce them. The genetic makeup of the farmers’ inventory of hop varieties are analyzed for DNA sequences that will code for the traits in question. These varieties are then crossbred through a controlled pollination process that produces new hybrid seedlings. Thanks to the random nature of reproduction, not all seedlings are created equal, and an intense screening process is undertaken by hop scientists to test for the best of the crop. These top hops can then be replanted and tested on a larger scale for both farming qualities and brewing characteristics.
It’s a painstaking, arduous process that takes years of trial and error to produce results. “Nelson Sauvin was 20 years in development which is fairly typical” says Donelan, referencing one of his home-grown New Zealand varieties, the latest darlings of the craft beer industry. Donelan has a distinct advantage over other hop growers in the Pacific Northwest and Europe: New Zealand is resistance to the diseases that plague hops elsewhere, meaning flavor and aroma can be prioritized in their research.
It certainly shows in the final product. Beer made with New Zealand hops display a uniquely intense floral aroma combined with juicy tropical fruit flavors. Apart from Nelson Sauvin, look for names like Motueka, Riwaka, and Pacific Jade on labels and tap lists to get a taste of these unique varieties. A readily available example is Anchor Brewing’s Humming Ale, a delicate pale ale hopped exclusively with Nelson Sauvin (Humming Ale, Anchor Brewing, San Francisco, CA. 5.9% ABV. $9 for a six-pack).
Even with this advantage, though, the epicenter of hop experimentation is an entire ocean away from New Zealand in the hills and valleys of the American Pacific Northwest. Growers stateside have made a name for themselves by introducing hop varieties that impart the big and bitter characteristics found in the quintessential American IPA and Double IPA.
The majority of these American hybrids are based off of Professor Salmon’s original Brewer’s Gold and Bullion varieties; the original “alpha” hops. The name references the alpha acid compounds in hops that are responsible for much of the bitterness in beer. Hops are ranked based on the content of these compounds, with the old lineage European varieties and newer “aroma” hops being on the low scale and “bittering” or “alpha” hops displaying higher concentrations. American farmers have embraced alpha acids so much that a new classification of hop varieties, “Super Alpha,” now exists.
This push towards big, bold hop flavors has become an identifying trademark of the American craft brewing. Hops certainly aren’t the only flavor contributor to the complex beverage that is beer, however. The malt bill, fermentation style, added ingredients, brew times, and even the water type play equally significant roles in the taste and aroma. Still, for many styles the hops define the beer. “Hops are arguably the most distinctive ingredient for affecting the ‘finish’ of the beer that leaves consumers with a defining flavor impression,” says Jim Solberg, CEO of Indie Hops, a craft-brewing focused group of farmers in Oregon’s Willamette Valley.
So the next time you fall in love with that lingering, bitter finish or intoxicating aroma from a hopped-up pale ale or tongue-buckling double IPA, take note of the hops used. With a little research you should be able to figure out what varieties produced those memorable flavors and aromas. Now you’ll have something extra to pull out of your back pocket when figuring out what new beers to try. And just think of how impressed the beer-guy behind the counter will be when you ask if he has anything brewed with Galaxy hops sitting on the shelves.
To get you started, here are a few examples of popular American-developed hop varieties and some beers that showcase their aromas and flavors.
This is the classic American hop. Descended from a cross between the wild English Fuggles and an obscure Russian-grown variety, it was the primary hop used in the early days of the American craft-brewing scene and is still a prominent player in many pale ales and IPAs.
Chico, CA. 5.6% ABV. $9 for a six-pack
The classic American hop is perhaps best showcased in the quintessential classic of the American craft brewing industry. A clean and straightforward beer that defines the American style, it displays the characteristic citrusy floral notes of the Cascade hop with a sweet caramel malt backbone.
Sometimes called Super Cascade thanks to its potent floral and citrus aromas, this hop variety is a mixed-blood stepchild of English and German varieties. It came about from crosses between the English Brewer’s Gold and Fuggles, East Kent Goldings, a German Bavarian variety, and an unknown variety.
Kalamazoo, MI. 7% ABV. $12 for a six-pack
Proving why Centennial got the nickname Super Cascade, this all-Centennial IPA displays aromas of pungent dogwood flowers, honeysuckle blossoms, and cooked pineapple. The taste follows suit with plenty of flowers and citrus topped off with bitter green tea and a toasty finish.
A cousin to Centennial, Nugget comes from crosses between Brewer’s Gold, Early Green, Canterbury Golding, a Bavarian variety, and an unknown variety. It displays many of the same aromas as its cousin but provides more bitterness and a sticky, resinous quality sought-after by many American craft brewers.
Hershey, PA. 7.5% ABV, $12 for a six-pack
This heavily hopped amber ale is brewed with several varieties but showcases Nugget. It displays unique aromas of classic cooking herbs like parsley and thyme above the usual citrus and pine notes. The herbs provide a nice bitter contrast to the sweet candied pineapple flavors that marry perfectly to its big and sticky mouthfeel.
This one has a little bit of everything. Descended from the noble German Hallertau, American Cascade, and English Brewer’s Gold and Early Green varieties, it has a delicate, peppery characteristic more reminiscent of the subtle European varieties than the intense American ones.
Portland, OR, 5.8% ABV, $7 for 22oz
Being located within the major hop-growing region of the Willamette Valley allows Rogue the ability to grow their own unique Revolution hop variety to use in this IPA, along with the Crystal hops that it showcases. Contrary to the name, the nose and flavor of this beer are distinctly organic, with grassy notes and layers of vegetal flavors.
This variety is a patented plant grown by Virgil Gamache Farms in Washington State. It’s actually a wild-type hop that was produced by spontaneous cross-pollination. Wild hops like Amarillo provide unique characteristics that intentionally cultivated varieties can’t produce, making them popular amongst more experimental brewers.
San Diego, CA
Green Flash uses what is known as “dry-hopping” to add additional Amarillo flavor to this brew. Dry-hopping means that hops are added to the beer during fermentation and allowed to steep in the liquid, kind of like tea. The process yields a beer with big floral aromas of pinecones and fruity pineapple with a well-balanced flavor profile of toasty caramel, bittersweet pine, and a squeeze of lemon.
The origins of the Simcoe hop are shrouded in mystery, thanks to a patent owned by the original growers of this variety. What is certain, however, is the role that it has played in the development of what was once called the “west-coast” style of IPAs. That name doesn’t really apply anymore, now that these big and juicy, tropical fruit-forward ales are brewed just about everywhere.
Easton, PA, 9% ABV, $10 for a four-pack
Weyerbacher’s double IPA is hopped exclusively with Simcoe but kept in check with a noticeable malty backbone. It’s a prime example of the amount of tropical fruit these hops can pack into a beer. There’s plenty of pineapple, mango, and watermelon all steeped in black tea and wrapped up in a burnt croissant. It’s sticky and sweet and a perfect summer sipper.