In early 2007, bigness was in style. It was the height of the extreme beer revolution, and though pale ales, IPAs and other classics remained the backbone of the industry, nearly every craft brewery in America had introduced its own barleywine, brawny Belgian style, double IPA, or something “imperial.” Dogfish Head led the movement on the East Coast, while out West, Russian River, Avery, Port and others were brewing up huge beers that assumed near-mythical status while turning the men and women who brewed them into celebrities.

But Max Toste wasn’t impressed. Not only that, Toste had grown downright cynical of nearly every beer hyped for its hop and alcohol content, and he was among the few beer devotees to downright reject extreme beers. Toste was at the time assembling a 90-plus beer list for his newly opened Boston bar, Deep Ellum, and among the very first beers he put on tap that winter was Beer of the Gods, a dainty 4.5-percent alcohol ale from High and Mighty Beer Company first brewed in 2006.

“Frankly, I was sick of high-alcohol beers,” Toste says. “I didn’t want to serve people something in a thimble and charge $9 for it.”

Beer of the Gods was everything that extreme beers crushed and superseded—a light, mild, and subdued ale that would quench one’s thirst before delivering so much as a buzz. In fact, Beer of the Gods was something of a spoof at the time, when all the geeks were raving and reeling over the dizzying experiments of craft brewers. But Toste offered it to his patrons with a straight face—and they drank it, not just at his bar but elsewhere. Not only that, a growing number of craft beer drinkers nationwide seemed to be waking up and gravitating toward other low-alcohol beers. Brewers began to catch onto the trend—and so it began, a widespread shift away from bigness, hops and alcohol, and the return of the session beer.

Session beers are loosely defined as low-alcohol but flavorful beers conducive to long, multi-pint “sessions” of sipping. Less a style than a description, session beers were once mainstays in Britain, where an active pub-going lifestyle was built long ago on low-alcohol brews. In America, we’ve done a respectable job of keeping our composure through 10 years of high-octane hop-bombs—but now, perhaps as a direct reaction, session beers have bubbled back into style. Beer of the Gods may have been one of the first, but many others have appeared since, including 21st Amendment’s Bitter American, New Glarus’s Apple Ale, Samuel Adams’ Rustic Saison, Drake’s Brewing’s Alpha Session and Ballast Point’s Wahoo Wheat. Some brewers, meanwhile, have gotten creative; by combining progressive experimentation with conservative sessionability, they have introduced curiosities such as Vanberg & Dewulf’s Lambrucha beer-culture hybrid and the Lacto-sour Berliner Weisse from Southampton Publick House.

And Founders Brewing Company in Michigan, with its 4.7-percent All Day IPA, is simply being honest about the very point of session beers—that is, drinking through a low-alcohol six-pack between noon and 9.

In Boston, one beer brand has made the session concept its entire foundation of business—Notch American Session Beer. To date, The Notch consists of three year-round beers and a rotation of seasonals. Founder Chris Lohring, a veteran East Coast brewer who bottled and distributed his first Notch batch in March, 2011, says the personal frustration of being unable to find low-alcohol craft beers prompted him to homebrew his own. Then, Lohring went commercial after conducting a few pub-special test batches and concluding that others were also looking for downsized beers.

So just how low in alcohol must a session beer go? In Britain, 4 percent ABV is the traditionally regarded cap, though American session advocates have allowed an unofficial limit of 5 percent. Some brewers are even stretching the boundaries. Full Sail’s Session Black, a dark lager, runs 5.4 percent, which may seem plenty sessionable—but session proponents won’t budge that far: Any beer over 5 percent, they say, does not qualify. Lohring, for example, draws the line sharply at 4.5 percent.

For Lew Bryson, too, the numbers matter. A beer writer in Philadelphia, Bryson is perhaps the most outspoken session beer advocate in America and is firm about the upper limits of sessionability. He writes a blog called “The Session Beer Project,” basically a one-man campaign started in 2009 to bring low-alcohol beer aboard the craft wagon. Having assumed the role as a session beer proselytizer, he sticks to a cutoff point of 4.5 percent ABV though he doesn’t split hairs if a session beer measures as high as 5—but that’s the absolute limit.

But when William Bostwick, beer critic for the Wall Street Journal, reviewed several session beers last June, he included nothing but 5-percent-plus beers in his lineup, creating a small storm of objections on the comment thread below the article. Bostwick later explained to me that he wasn’t interested in percentage points and that he chose his session roster based on each beer’s uniqueness, intrigue and charisma. He did pay some mind to alcohol, too, reviewing no beers more than 5.4 percent. Among his choices were Full Sail’s Session Black Lager and Great Divide’s Samurai, which is brewed with a helping of rice in the kettle.

Whether “sessionable” beers really are increasing in number or volume and edging others out of style remains unclear. Journalist and regular contributor to All About Beer Magazine, Ken Weaver, has analyzed data from RateBeer.com’s archives and calculated that session beer production is actually decreasing and that average ABV of American beers is holding steady at 6 to 7 percent.

And there is no doubt: Festivals featuring Double IPAs, barleywines, sours, and other extreme styles have become hugely profitable events, and they seem to get larger every year as more people tune into the buzz about big, exciting beers—those charismatic beers that draw cult followings and turn brewers into stars. Session beers lack such power, no doubt—but that’s okay, because their job is simply to be quiet and be sipped.

Still, at Deep Ellum in Boston, session beers are doing the best thing of all for Max Toste: They’re making him money—more money, he believes, than extreme beers could generate. This was, Toste concedes with a splash of straight-faced honesty, exactly what he was hoping for.

“Professionally, I sell beer,” he explains. “And I want to sell people more beer but not get them [wasted].” And Toste isn’t just selling light beer: “I’m selling the [a lot] of it—and it makes sense, because you can drink four or five.”

Saturday April 7th is Session Beer Day.