Each year, in the lush fields of the Pacific Northwest, dozens of experimental hop breeds are planted, most only identified by a string of numbers like a shadowy government project. These fledgling varieties are often the result of crossing existing strains in hopes of, say, increasing mildew resistance, amping yields or devising unique flavors. Each year, large craft breweries examine these numbered hop breeds not yet in the marketplace, hoping to answer a single question: Can this hop make a great new beer?

Often, the answer is no, but every once in a while, a hop shows serious promise. In this case, the hop is named, it graduates from lab to brew kettle and the experimentation begins. Just in time for warm weather, a handful of new hop varieties have proven their mettle and made their way into a crop of refreshing beers. With notes of earthy citrus, tropical fruit, white wine or floral tea, they’re adding distinct complexity to everything from IPAs to ESBs, and they’re inspiring brewers to craft a whole new style of summertime brews.

Delta Force

Last summer, international agricultural company Hopsteiner rang the crew at Boston’s Harpoon Brewery and made an offer as mysterious as it was alluring. The hop merchant had created an experimental hop variety dubbed Delta. Would Harpoon be interested in buying some of the crop? Always eager to do some R&D, the brewery accepted, then set out to decode the Delta hop’s riddle. “There’s absolutely nothing online about this hop,” says Harpoon brewer Charlie Cummings. “Hopsteiner doesn’t even list Delta on its website.”

Cummings and his crew found out that Delta is a cross of two well-known varieties: the earthy English Fuggles and floral Cascade—the quintessential flavor of West Coast beers—which is itself a blend of Fuggles and the Russian hop Serebrianker. When the hops arrived at Harpoon, Cummings brewed a test batch of a British-style extra special bitter (ESB), liberally dosing it with the Delta for both aroma and bitterness. His first taste was a revelation. “Fuggles is usually a pretty subtle hop, but this had a stronger, more assertive character—an American punch,” he says. The flavor was similarly complex, with citrusy, melon-like notes and an herbal, grassy quality. “We made a very quick decision to brew that ESB as one of our 100 Barrel Series beers,” Cummings says, referring to Harpoon’s line of experimental beers.

The result was the Single Hop ESB, America’s first production beer to feature the Delta hop. It balances the beer’s nimble, malt-forward body with a fruity kick. It’s a familiar yet foreign flavor, one that’s as pleasing as it is perplexing. “People are always looking for the next new hop,” Cummings says, “and this is a pretty great one.”

The Full Nelson

While some hop applications are discovered in a lab, others are found by serendipity. A couple years back, Pat McIlhenney, brewmaster and owner of Southern California’s Alpine Beer Company, traveled to New Zealand where he grew smitten by the excellent growing conditions and botanical advancements of the country. Upon returning to California, the 56-year-old began researching New Zealand hops and discovered that because there are few natural pests and no known hop diseases, New Zealand hops require few, if any, pesticides. Add the fact that the growing season is the opposite of North America’s, and a favorable exchange rate makes them cheaper (even factoring in shipping), and McIlhenney was sold.

He chose, among others, a breed curiously named Nelson Sauvin. “It’s got an intense, grape-like quality,” McIlhenney says of the strain, which recalls Sauvignon Blanc and a touch of tropical flavors. (Nelson refers to a region in central New Zealand, while Sauvin is shorthand for Sauvignon.) “It shaped up to be an exceptional hop.” He quickly found a home for Nelson Sauvin in his rye-spiked IPA named, naturally, Nelson, and it became one of Alpine’s top sellers, giving McIlhenney an envious problem: “We sell it faster than we can make it,” he says.

Should you be unable to source Nelson, no fear: Other brewers are quickly cottoning to the quirky New Zealand hop. It’s incorporated in beers such as Stateside Saison from Stillwater Artisanal Ales in Baltimore; Big Barrel Double IPA from San Diego’s Karl Strauss; and Punk IPA from Scotland’s BrewDog. “It’s one of our favorite hops to use,” says co-founder James Watt, who rhapsodizes about Nelson Sauvin’s flavors of lychee and mango. And though McIlhenney is loath to sing his beer’s accolades too loudly (“That’s like naming your favorite child,” he says), he can’t help himself: “Nelson is one of my wife’s and my favorite beers. When a beer is that good and stands out that much, it’s hard not to be excited.”

Coming Up Ace

Over in Massachusetts, Jeremy Goldberg was having an issue with his IPA. Namely, it wasn’t selling well. So when the 34-year-old head brewer and co-owner at Cape Ann Brewing discovered that his supplier was discontinuing Brewer’s Gold—a piney, pungent British bittering hop that flavored his IPA—he took it as a sign to re-jigger the recipe. Some of his employees, who were avid homebrewers, told Goldberg about the unusual Sorachi Ace hop. Japan’s Sapporo Breweries originally developed the variety, but the brewery was unable to find a use for the uniquely lemony hop. Goldberg would. To temper Sorachi’s citric character, he paired it with the herbal Chinook hop, creating an earthy, piney IPA with a bright, citrusy aroma.

Whereas Cape Ann uses Sorachi Ace as a flavoring component, New York’s Brooklyn Brewery created a summery beer expressly as a platform for the singular hop. “When I smelled Sorachi Ace, the first thing that came to mind was, ‘That’d make a great saison,’ ” says brewmaster Garrett Oliver. For last summer’s Brewmaster Reserve series, he created the dry, austere, single-hopped Belgian-style saison called, fittingly, Sorachi Ace.

Though Oliver was confident that the beer would do well, the results outstripped his expectations. Sorachi Ace became the fastest-selling release in the series. While the inventive Brewmaster’s Reserve beers (like the Cookie Jar Porter) are mainly one-offs and rarely bottled, the love for Sorachi Ace led Oliver to revive it for this spring and summer. The beer rolled off the factory line in large-format bottles, but the production run might be a tad smaller than expected. “People working at the brewery said, ‘It’s a shame that some of these will accidentally be misplaced,’ ” Oliver jokes.

Tea Time

Some hops aren’t even developed with beer-making in mind. The Teamaker hop was developed several decades ago by researchers at Oregon State University’s USDA laboratory. The scientists’ goal was to harness the natural antimicrobial properties of hops while subtracting the trademark bitterness caused by the flower’s alpha acids. Teamaker was engineered with low alpha acids and high beta acids, which impart aroma but no bitterness—like the perfect cup of tea, hence the name.

One of Teamaker’s proposed applications is livestock production. In lieu of antibiotics, the hop could be incorporated into animal feed to lessen microbial and fungal illnesses. That’s great news for farmers, but brewers were nonplussed. “It was a homeless hop,” says Widmer Brothers co-owner Rob Widmer. He first heard of Teamaker from longtime Oregon hop grower Goschie Farms and was intrigued: “You can have too much bitterness, but you can’t have too much hop aroma.”

Widmer Brothers is one of America’s first brewers to experiment with the Teamaker hop, brewing its first batch of TEAser Pale Ale in 2008. If you were lucky enough to get a pint, you would’ve found a heady aroma of grassy, floral hops. But sipping the pale-golden TEAser would reveal that the piney aromatics and gentle, iced tea-like flavors didn’t correlate with the beer’s bitterness—or lack thereof. “You get a wonderful bouquet without the beer being a tongue-scraper,” says Widmer. The brewery has used Teamaker to make TEAser Pale Ale twice, though the brewers were unable to resist including a tiny amount of traditional hops. They’re planning to brew it again, but there’s no confirmed date. “Next time,” Widmer says, “I’d be tempted to skip the bittering agents completely.”

Secret Citra

Since most brewers have access to the same hops, having the means to create a proprietary variety with uncommon aromatic and bittering qualities can pay delicious dividends. A few years ago, the brewers at Sierra Nevada were aflutter over hop variety 394. In conjunction with Deschutes and Widmer Brothers, Sierra Nevada helped finance the research and development of this strain with a strange flavor profile—a hard-to-pin mix of citrus, mango and papaya. “There’s even something strangely Southeast Asian about the hop,” says Sierra Nevada’s Bill Manley. “This was one of the most promising hops we’d seen in some time.”

Sierra’s brewers played around with 394, polishing and tweaking recipes to serve as the novel hop’s coming-out party. By late 2008, Sierra Nevada had its eureka moment. The tropical 394, christened Citra, would drive the flavor of the Torpedo Extra IPA. When it was released in early 2009, it was Sierra’s first addition to its year-round lineup since 1992.

If that sounds like a lot of time and research to spend on developing a beer for a single hop strain, it is. But unlike small brewpubs or microbreweries, Sierra Nevada and other larger brewers are uniquely positioned to do the time-consuming legwork. “We have labs and a researcher with a background in hop compounds,” says Manley. “Smaller craft brewers would just have to buy a lot of hops and hope for the best.”

Since Sierra Nevada cracked the seal on Citra, other brewers have quickly adopted the hop. Widmer Brothers recently released its golden Sunburn Summer Brew, while Deschutes used Citra in its Hop in the Dark black IPA. In Madison, Wis., Ale Asylum’s Bedlam! mixes Trappist yeast with Citra, while Flying Fish’s Exit 16 Wild Rice Double IPA is generously dosed with Citra. With the word out, now amateur brewers are clamoring to experiment with the trademarked hop. “We get frequent requests from homebrewers asking where to find Citra,” Manley says. “It just takes somebody to break the ice.”

RELATED CONTENT

Check out the July/August 2010 issue for tasting notes of beers using the hops talked about this article, as well as a Q&A with hop farmer Jason Perrault, who helped develop the new Citra hop.