Not long ago, I found myself in a beer-tasting room in upstate New York, looking out on a field of hops and sampling the craft brews of a company called Indian Ladder Farmstead. Among the list of beers chalked on a blackboard was one particularly hoppy creation named “Dr. Paul Matthews I.P.A.” Naturally I felt obliged to inquire about the eponymous doctor. The owner, Dietrich Gehring, told me that the name was an homage. He said his passion for wild hops had led him to Matthews, to whom he referred as the Lord of the Hops.

“I’m not an expert in beer,” Matthews cautioned when I reached him, by phone. “I’m a plant engineer and evolutionary biologist.” Matthews, a past president of the Hop Research Council, is the senior research scientist at Hopsteiner, a major hops trader and processor, founded in 1845, in Washington State’s Yakima Valley.

The hop flower has been used in beer-making at least since the eighth century. Traditionally it was a preservative, but it also imparts flavor. To some, the taste is bitter and unpalatable, and thus many brewers use only minimal amounts. But, depending on variety, growing conditions, and other factors, hops can impart a range of flavors that connoisseurs say rivals that of wine grapes. Starting in the nineteen-seventies, small brewers on the West Coast began dramatically upping the amount of hops in their brews. One of their most popular products was the India pale ale, or I.P.A., a brew that has been around since the late eighteenth century. The story goes that necessity drove the British to add large quantities of hops in order to preserve the beer they shipped to India, to quench the thirst of the Sahibs managing the Empire there.

The hop flower has been used in beer-making at least since the eighth century. Traditionally it was a preservative, but it also imparts flavor. Photograph by Berthold​ Steinhilber / laif / Redux Photograph by Berthold​ Steinhilber / laif / Redux

Over the past decade, varieties once thought of as boutique beers, such as I.P.A.s, have exploded in the United States, thanks to the locavore movement. Craft brewing is now doubling in sales, by volume, every five years; today, craft-beer sales make up twenty-one per cent of the beer market, and twelve per cent of the volume. The Brewers Association, a craft-brewing trade group, expects craft beers to have a fifty-per-cent market share in a decade. Since craft brewers use about ten times more hops than megabrewers, the trend has been a bonanza for Hopsteiner and the other big hops companies.

But while an emphasis on hops has likewise boosted the business of small-scale brewers, I.P.A. aficionados are known to be among the most fickle of beer consumers, flitting from one label to another in their endless search for new flavor elements. That puts pressure on brewers to come up with new beers, which, in turn, leads to a hunt for new hops varieties.

Enter Paul Matthews, who is to hops what John James Audubon was to birds. He has been involved in the search for wild hops strains from Colorado to the Caspian Sea; from these he teases out flavor components. Spicy, floral, grassy, citrus, herbal, evergreen: the horizon keeps expanding, and still the crowd wants more.

“We’re currently looking at the Sky Islands of Arizona,” Matthews told me. These mountaintops, surrounded by a hundred miles of desert, form unique ecosystems. “We expect that a variety of hops found on one of these mountains will not have mated with hops on another,” he said. “The hypothesis is they would be diverse from each other. If there’s a hop that’s been isolated for, say, a million years, we want to know about it.” After finding a new species, he is careful to engage in “germplasm banking”: conserving samples by storing them in a local repository.

Flavor is driving the hunt. But, as it turns out, Matthews himself is not only, or even mostly, interested in flavor. The scientific byways, and possible medical uses, are more intriguing to him: the hipster I.P.A. quaffers are, in effect, advancing the frontiers of pure science, enabling the sequencing of the hop genome, and funding ethnobotanical excursions. “I was just in Tbilisi, at the Georgian botanical garden,” Matthews said. “People in Georgia are still into agroforestry—they pick wild strawberries and things in the forest. It turns out rural Georgians have for a long time used wild hops to cure their breads. Hops makes a powerful broad-spectrum antibiotic. It stops bacteria from souring the bread.”

The Georgians have also used hops as a folk medicine for reproductive health, to treat uterine pain, for example. This makes sense to Matthews since hops contain the strongest known plant-derived estrogen. “We are seeking to engineer it,” he said. “We think it can be used for hormone-replacement therapy—for example, in postmenopausal women.”

But perhaps the most exciting frontier, he told me, concerns the relationship between hops and cannabis: “Hops and hemp are both members of the Cannabaceae family, and they have many similarities. Both are grown as spice plants—that is, grown for their chemical content. And both are used medicinally.” It’s thus intriguing for scientists like Matthews to study the two side by side. Medical implications seem likely, but, in addition, for some craft brewers a hemp-hop marriage is a possible Holy Grail of flavor. “There’s a big crossover in flavor combination of the two,” Matthews said. “The flavor profiles are both based on terpenes, which are essential oils, like mint. By studying the terpenes in both we can learn a lot more about flavor and diversity.”

While it is entirely possible to make psychoactive beer, Matthews seemed uninterested in the concept. And while Hopsteiner is studying hemp, Matthews stressed that the company does not have a hemp-breeding program. But, he said, somewhat mysteriously, “It is being explored elsewhere. Brave people are doing that work right now.”