Beer’s third-most-important ingredient, after water and barley, is almost as mystifying to most beer drinkers as Prohibition. But a new kind of beer has recently emerged that gives consumers an unprecedented ability to learn: the single-hop India pale ale.

It’s a style that demonstrates, as Boston Beer President Jim Koch once put it, that “hops are to beer what grapes are to wine.” Like grapes, the resinous flowers of Humulus lupulus are agricultural products that come in distinctive varieties, each with its own flavors and aromas. Instead of syrah and cabernet, the beer world has Simcoe and Cascade.

Most beers are brewed with a mixture of hop strains; brewers use some kinds primarily to produce a beer’s bitterness and others to add fruity, floral or herbal aromas. (Potent double and imperial India pale ales often pile them on: Founders Brewing’s Devil Dancer, for example, includes 10 varieties of hops.) Other beers, such as the 19 IPAs in the Single Hop Series from Denmark’s Mikkeller, use just one. That makes it possible for drinkers to understand the difference between, say, an earthy European hop such as East Kent Goldings (often featured in English bitters) and a fruity American hop such as Amarillo (a mainstay of West Coast IPAs), or to identify the nuances of similar varieties from one growing region.

Another cause of the single-hop trend is that hop research centers in the Pacific Northwest have churned out new hybrids with specific desirable traits, often by collaborating with commercial breweries. A good example is Citra, which has an unusual mix of citrus and tropical fruit flavors. The development of the strain was financed by Sierra Nevada, Deschutes Brewery and Widmer Brothers, and after Sierra Nevada introduced Citra in 2009 in its Torpedo IPA, it quickly became one of the beer world’s trendiest hops.

ChurchKey’s Engert underscores the contribution of Mikkel Borg Bjergso, the single employee of Mikkeller, whose Single Hop Series first appeared in the United States in 2009, around the start of the single-hop wave: “He’s been a big driving force.”

Bjergso’s full series was on tap at ChurchKey in June. The Palisade, named for an American hop variety that is related to the German Tettnanger, was dry and peppery, with a musty, honeyed aroma. The Amarillo, a fruit bomb emphasizing grapefruit and tropical fruit, had a bitter citrus-peel quality and a hint of spiciness.

The Centennial was similar but not so lush, with a purer, slightly grassy flavor, and the Citra was especially aromatic; it smelled like passion fruit. It was hard not to think about a Riesling, or maybe a sauvignon blanc.

Fromson is an associate editor at the Atlantic.