By the fourth season of The Simpsons, Duff Beer had stepped clearly beyond the background to begin to power entire episodes.

On Sunday, Jan. 21, 1990, about 8:15 p.m. Eastern Standard Time, Homer Simpson saw a commercial for Duff Beer. His thirst piqued, the 38-year-old married father of three got off the couch and went to the fridge to grab a can of the brew. He found none—perhaps having already drunk his usually steady supply, it’s never clear—but one of the most famous beers ever had loosed itself upon popular culture.

A quarter-century later and the world still cannot get enough of that wonderful Duff. A late May Google search for “Duff Beer” turned up 963,000 results in under a half-second. A pub within Universal Studios Florida’s fantastical boundaries serves Duff beers. Other iterations—unsanctioned by Fox Broadcasting, the production juggernaut that took a chance on The Simpsons 25-plus years back and has been handsomely rewarded—continue to pop up on at least six continents (I bought a can of German-produced Duff years ago at a souvenir stand just outside the Vatican while shopping for Rosaries).

There is Duff merchandise, including pub mirrors, glassware and T-shirts; Duff trivia; Duff fan testimonials online; even tasting notes on the stuff that I am not sure are entirely in jest.

There is, of course, too, an entire backstory to Duff, born along by the show itself, which is now going into its 27th season, the longest-running scripted show in American television. Some of it is folklore, other parts of it hard fact. Let’s try to sort things out, starting with the name.

Guns ‘n Roses ‘n Beer…

Various theories about how Duff got its name have emerged in the last quarter-century. One has it that the beer was named for Duff McKagan, rhythm guitarist for Guns ‘n Roses (remember them?). Another is that Simpsons creator Matt Groening had come up with most of the tagline, “Can’t get enough of that wonderful…,” and needed something that rhymed to finish it. Another theory hypothesizes that Duff was simply a spin on Bud, the ubiquitous red-and-white flagship brand of Anheuser-Busch InBev.

So which is it? A little from column A, a little from column B.

Jay Kogen co-wrote that Jan. 21, 1990 episode, “Homer’s Odyssey,” in which Duff debuted. “Wally Wolodarsky and I came up with the name when we were writing the episode it first appeared in,” Kogen said in an email. “We thought Homer would drink an American beer like Budweiser, which everyone calls Bud. So we wanted a one-syllable name. We came up with Duff because it sounded funny and it’s a synonym for butt.”

That Homer was literally sitting on his butt/duff when the beer commercial aired during that inaugural episode only helped matters along, Kogen said. As for that tagline, he added, it edged out the less cadence-friendly, “Relax with a cold Duff in your hands.” (There have been shorter-lived and lesser well-known taglines, too, including in that “Homer’s Odyssey” episode: “Duff, the beer that makes the days fly by!”)

Wes Archer directed “Homer’s Odyssey.” He seconded Kogen’s Duff-butt correlation. The episode, after all, hinged on a demoralized, recently laid-off Homer psyching himself up again—a.k.a. getting off his duff and into the wider world of Springfield, U.S.A.

Archer also directed All About Beer Magazine to a November 2012 tweet from David Silverman, an animator and a director for The Simpsons since it was sketch filler in the late 1980s for the Tracey Ullman Show, another Fox vehicle (Silverman directed The Simpsons Movie, too). Silverman tweeted that Groening did, indeed, come up with Duff to rhythmically complete the tagline, “Can’t get enough of that wonderful…”

“This I trust to be gospel,” Archer said, “because I know David well.”

The genesis of the world-famous name might have in the end been a need for both rhyme and synonym. Kogen did credit Duff’s development to the wider creative forces amassed in service of The Simpsons, which, though it seems inconceivable now, had no assurance of long-term success—the last primetime cartoon to catch on was the decidedly more subdued Flintstones. “Nothing we wrote,” Kogen said, “didn’t also go through the minds of executive producers Sam Simon [and] Matt Groening, and writers Al Jean, Mike Reiss, George Meyer, and Jon Vitti, who were all part of the early staff.”

Tartar Control Duff

If the name sprung merely from a need to embody part of the plot of “Homer’s Odyssey,” then that suggests Duff’s creators never intended the beer to play that big a role (remember: no one yet knew if the show itself would last that long). By the fourth season in late 1992, however, Duff had stepped clearly beyond the background to begin to power entire episodes. (Please excuse the summaries below—watching Simpsons episodes is a lot more entertaining than reading synopses, I know.)

In episode 13 of the fourth season, we discover Duff Gardens, a thinly veiled spin on Anheuser-Busch’s Busch Gardens. Duff Gardens is basically an over-the-top homage to its namesake beer, a brewery-run amusement park packed with thinly hidden dangers, including the hallucination-inducing water for “The Little Land of Duff” ride and a beer-bottle mascot aptly named “Surly.” Duff Gardens also includes the “Beerquarium, home of the world’s happiest fish”—a danger less to humans than to aquatic life. Confrontations with these dangers power the episode’s plot. (Click here to watch a clip.)

The “Duffless” episode a few weeks later started with Homer and his best pal Barney, who cracked his first Duff as a teenager and kissed any future quickly good-bye, visiting the Duff Brewery. Through their tour, we learn of other Duff beers beyond the flagship brand: Lady Duff, Raspberry Duff, Tartar Control Duff and Duff Dark, to start, as well as a line of Duff Gummy Beers candy. We also discover during the tour that John Kennedy was a Duff drinker, while his 1960 opponent, Richard Nixon, only said he was. (“That man never drank a Duff in his life,” Homer declares.)

Toward the end of Homer and Barney’s time at the brewery, Duff Dry and Duff Lite are introduced—they come from the same giant pipe pouring forth regular Duff, suggesting all three are the same beer. Post-tour, the normally hapless Springfield police chief, Clancy Wiggum, incognito as a giant beer stein, pinches Homer for a DUI, setting in motion the episode’s plot: Homer giving up Duff for a month, his longest stretch ever; he loses a lot of weight and gains a lot more spending money.

From these fourth-season episodes onward, it wasn’t unusual to see Duff at crucial plot points—or at least as fodder for ready punchlines and gags, which for one thing revealed a broad universe of Duff. These included foreign iterations such as Canadian Duff (labeled as Le Duff avec Codeine for that nation’s French-speakers) and the Duffo, a Cuban version advertised with images of Che Guevara. And we mustn’t forget Duff Stout—according to the brewery, “the beer that made Ireland famous.”

There was also the non-alcoholic Duff Zero, revealed in “Homer vs. the Eighteenth Amendment,” the 18th episode of the eighth season, when overindulgence in green-colored Duff during St. Patrick’s Day spawns Prohibition in Springfield. This would appear to be the polar opposite of Duff 200, a 200-proof version introduced in season 21 through a billboard with the slogan “Nothin’ But Booze.”

And who can forget the beer’s indefatigable mascot and spokesperson, Duffman? He first appeared in 1997 in season nine’s “The City of New York vs. Homer Simpson,” a rarely re-aired “lost episode” because it prominently featured the original World Trade Center towers. Homer briefly became Duffman in the 17th episode of season 26 when Barry Huffman, the mild-mannered alter ego behind Duffman, injured himself.

Or how about Moe Szyslak and his Moe’s Tavern, a show staple before season one, when both appeared as part of the first holiday special in December 1989? Moe’s Tavern carries the highest-brow iteration of Duff yet: Henry K. Duff Private Reserve. Unlike twist-offs of regular Duff, this darker beer apparently requires a bottle opener.

There is also Duff Stadium and the Duff Blimp often found above it. In the fourth episode of the fourth season, Homer wins a ride on the zeppelin, only to sell his ticket to Barney to pay daughter Lisa’s entry into a local beauty pageant. Barney subsequently crashes the blimp.

“Only a swine…”

All of this still leaves the obvious question: What is Duff, exactly? What is the beer that Homer Simpson took from his fictitious fridge in the house on Evergreen Terrace 25 years ago and lifted to iconic status? Clues abound.

First, its basis on Bud. The creators of Duff, as Jay Kogen pointed out, used that Anheuser-Busch brand as their cultural touchstone. Also, Duffman bears a striking resemblance to Bud Man, a red-suited, blue-caped Anheuser-Busch mascot introduced in the late 1960s and mercifully since discontinued. Finally, of course, there is Duff Gardens-slash-Busch Gardens.

Like Budweiser, then, we can assume that Duff is likely a lager and an American-style macro-pilsner at that. (For the record, the Universal Studios Florida pub touts its Duff as an amber lager, its Duff Lite as a traditional pilsner and its Duff Dry as a toasted dark ale—but those creations are barely two years old and bear little resemblance to the creation myths that the show established.)

Second, Duff is cheap. Or at least it’s cheap enough to be a staple of Moe’s Tavern—where patrons “seek the darkness,” according to its namesake—and to be readily available, starting in the early 1990s, at the Kwik-E-Mart, a convenience store of dubious hygienic quality and worker safety. So, we can assume that Duff is likely an American-style macro-pilsner that doesn’t cost that much to buy nor, really, to make (recall the Duff Brewery tour and its production shortcuts for Duff Dry and Duff Lite).

Third, Homer and co. drink Duff for its kick, not its taste, suggesting that the result of these shortcuts is a bland brew best drunk ice-cold. In that eighth-season Prohibition episode, the Duff Brewery tried to ride out the ban with that alcohol-free version. “Our customers buy Duff for its robust taste, not its alcoholic content,” declares Howard K. Duff VII (himself another veiled reference to the Roman-numeral-heavy dynasty that once controlled Anheuser-Busch). “I predict our new alcohol-free Duff Zero will sell even better than our previous brand.”

The brewery closed almost immediately.

Finally, we have the assessment of northern Europeans, the people who brought us, for better or worse, pretty much every known beer style. In “Burns Verkaufen der Kraftwerk,” the 11th episode of season three, a depressed Mr. Burns, Homer’s boss, sells the nuclear power plant to a pair of German investors. How did they even know it was for sale? By accidentally running into Homer at Moe’s Tavern. Homer recommends—what else?—a Duff and one of the Germans kindly demurs.

“My English is not perfect,” he says, “but I have to tell you your beer is like swill to us.
Only a swine would drink this beer.”

That was in December 1991. The American beer scene has changed considerably since then, to say the least—in terms of diversity of styles, number of breweries, quality of output, savviness of the consumer, etc., ad infinitum. Did a quarter-century of Duff have anything to do with that? Even accidentally? Tangentially? Fake though it may be, it is one of the most famous beer brands ever.

John Ortved wrote a 332-page history of The Simpsons, published in 2009. Duff “never really arose in my interviews,” Ortved told me. Kogen, co-writer of that first Duff episode in January 1990, said he assumed the creative staff “were beer drinkers, although it wasn’t something we did at work.”

According to Maureen Ogle, author of Ambitious Brew: The Story of American Beer, any impact Duff may have had on beer is confined to perception. “I don’t think Duff has had any impact on anyone, anytime, anywhere,” Ogle said in an email. “Except that, alas, it has reinforced the notion of beer as a ‘working-class’ drink. Which probably wasn’t The Simpsons‘ creators’ plan… but…”

Maybe that’s just it: Duff spilled forth 25 years ago, before the advent of beer geekdom. It was a less-complicated time for the drink. Homer Simpson, “one of the carbon blobs from Sector 7G” at the Springfield Nuclear Power Plant, sitting on a couch pulled from the garbage in front of his neighbor Ned Flanders’ house, simply needed a beer to call his own.

And there was born that wonderful Duff.

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Tom Acitelli is the author of  The Audacity of Hops: The History of America’s Craft Beer Revolution. His new book, American Wine: A Coming-of-Age Story, is available for pre-order. He has been watching The Simpsons since he was 12 and has yet to open that can of Duff he bought outside the Vatican. Reach him on Twitter @tomacitelli.