“I’ve been coming here since 1978, when I was 17,” says writer and historian David Wondrich, as he settles into an outdoor table at McSorley’s Old Ale House, the celebrated Irish bar that opened in New York’s East Village in 1854. Wondrich is seated alongside writer Noah Rothbaum, with whom he recently completed and published The Oxford Companion to Spirits & Cocktails, 10 years in the making.

The monumental 864-page tome weighs in at over three and a half pounds and is packed with 1,150 entries written by more than 160 contributors. (Wondrich wrote about 250 of them and co-wrote another 50.) He signed on as editor-in-chief, but about two weeks in knew he needed help and enlisted Rothbaum as associate editor.

As demonstrated in his articles and books, including the award-winning Imbibe!, Wondrich is dedicated to a highly detailed level of research. He applied the same techniques to this project, investing in professional subscriptions to a dozen databases to track down factual minutiae, from historic newspapers to military records. “You won’t believe the amount of time I spent on these sites trying to find years of birth and death for bartenders and distillers,” he says. The project confirmed the value of the strategy he used for Imbibe!, which he calls, Chase Down Every Rabbit. “Because you never fucking know where that rabbit is going to go,” says Wondrich. “Rabbits are twisty things, you know? And they find holes in places where you didn’t know there were holes and then you get into their burrow and there’s a million things in there.”

Beyond the sheer scope of the compendium, knowing that it would stand spine to spine in the Oxford Companion library carried its own level of anxiety. When Wondrich started the book, he kept Jancis Robinson’s The Oxford Companion to Wine and Garrett Oliver’s The Oxford Companion to Beer close to his desk, but realized he’d never get his book done if those two were staring him down. “I’d look up at these huge, polished, incredibly well-done books and I had to kind of put them aside,” says Wondrich. “Harold Bloom’s anxiety of influence was just too high. Ultimately, I haven’t really gone back to compare them, because it will make me sad.”

So, what does Wondrich feel like now that the book is finally published? “Relief at a level I did not know existed,” he says. “I’ve got a lot of normal everyday stress and emails out of control and deadlines, but I don’t care. Nothing can compare to having the knowledge that I [had] 400 entries left to edit and 120 left to write.”

Now, with all of that anxiety in the rearview, Wondrich and Rothbaum share their five favorite surprises uncovered or encountered while researching The Oxford Companion to Spirits & Cocktails.

Campari’s Roots Are… British?

The direct connection between Campari and Stoughton’s, the 17th-century London bitters considered to be among the first of their kind, was hiding in plain sight. Leo Leuci, whom Wondrich calls “the dean of Roman bartenders,” was at the Campari museum in Milan and sent Wondrich a photo of the original recipe for Campari, as written out in Gaspare Campari’s notebook. While Campari was then known as Bitter all’Uso d’Holanda (Holland-style bitter), the notebook called it Stoughton d’Holanda. “It had things crossed out and writing all over it. It was clearly a recipe that was much used and amended over time,” says Wondrich, who uncovered other copies of the original Stoughton’s Bitters recipe in Italian distillation books.

Stoughton’s Bitters began when Richard Stoughton started making a commercial alcoholic extract of bitter herbs (with a distinctive orange-red color) that, when added to wine, beer or brandy, served as a palliative to aid digestion. “That’s the beginning of the cocktail right there—the sweet, diluted spirits of the time plus bitters,” says Wondrich. “Then, in the middle of the 1800s, Gaspare Campari brushes off the old Stoughton’s recipe, tinkers with it, dilutes it to sipping proof. It’s like, goddamn, this goes right back to the beginning of modern mixology.” Rothbaum lights up talking about this documented jump from nonpotable to potable bitters and their consumption from medicinal to recreational. “It’s kind of the missing link,” Rothbaum adds. “This is our Lucy.”

The American Three-Chamber Still, Lost and Found

The technical history of distillation turned out to be a major part of The Oxford Companion to Spirits & Cocktails, but a little book on the subject published in San Francisco in the 1860s, which Wondrich uncovered at The British Library in London, changed everything. The book described in detail a cheap, effective and universal “American still” that used steam to extract the distillate, as well as oils and aromatics, from the grain. This three-chamber still represents a link between the traditional pot still and the more modern column still, and was used almost exclusively by whiskey distillers before Prohibition. By World War II, when distillers under government contract were required to use column stills, it had all but gone extinct.

“From pot still to column still is a long, twisty process and when you start really looking into it you realize how much has been streamlined in its history,” says Rothbaum, who credits Colorado distiller Todd Leopold, one of just two distillers currently using a three-chamber still, with helping the authors understand the importance of it. “It’s only then when you realize that something of that magnitude can be completely cut out of history.”

Bourbon and Rye: Complicated Bedfellows

While they each have their own histories, mash bills and production methods, bourbon and rye are often grouped together, and seen as interchangeable in a drink. But which spirit you produced or consumed was often a nuanced affair and had a lot to do with where you were from and even your political leaning. “There’s obviously a lot of conflict that shapes those spirits over time and there’s a real competition between the two of them,” says Wondrich. Even when bourbon producers started making rye, Rothbaum notes, it wasn’t in a noble effort to save an American tradition, but out of necessity. “It was not harmonious. They hated each other,” he says. “Bourbon distillers were in such a bad place in the ’70s and ’80s they were willing to make their mortal enemies.”

This extended to consumer choice. Whether you preferred bourbon or rye in your Manhattan or Old-Fashioned defined what kind of person you were. “That went all the way to the White House,” says Rothbaum. “Depending on who was in office, D.C. was either a rye town or a bourbon town. These were real things and it said a lot about you. You drank this, or you drank that. That was it.” And in case you’re wondering, Wondrich offers that Kennedy was a rye guy. He drank Overholt.

Rum Isn’t From Barbados After All

“We’re always told rum was invented in Barbados. But when I started researching this thing, it caught me by surprise,” says Wondrich, who notes that while the earliest confirmation of cane spirits in the New World can be traced to around 1600, there is archeological evidence of distillation in India’s cane-growing regions from the 700s. Its presence in Northern India is documented in the late 1200s, with cane arrack widespread in Bengal by the 1500s, where the Portuguese established colonies in the 1510s.

In both Portuguese and Spanish America, during the process of boiling sugar cane down to crystallization, the impurity-rich froth known as the “skimmings” was given to the enslaved workers, who would ferment a drink from the discard. In the early 1600s, the British colonized Barbados and, using guidance from Dutch colonists, began distilling and selling those skimmings into “rumbullion” or “rumbustion.” In the 1680s, they started adding molasses to the process, which produced a much stronger fermentation, and marked the beginnings of rum as a commercial product.

“We don’t know how this distilling began, but it is possible that it was introduced by soldiers or sailors who had seen it in Bengal,” says Wondrich, who credits anthropology professor and author Frederick Smith for opening his eyes to the breadth of research to uncover. “We didn’t realize how these things were interconnected,” he says. “It’s the origin of rum in the New World.”

Ciro Capozzi’s Influence on European Bartending

While researching Harry MacElhone, founder of Harry’s New York Bar in Paris, Wondrich discovered that he also had been the opening bartender at Ciro’s Club in London in 1915 (much earlier than Wondrich had thought), which led him to Ciro Capozzi (1855–1938), an influential bartender who turned out to be a far more interesting character than MacElhone.

The Neapolitan son of a sea captain learned his craft in Italy before moving to New York, where he worked with the legendary bartender Jerry Thomas near the end of Thomas’ life. But the first ripples of Capozzi’s lasting impact started when he opened his own bar in Monte Carlo in 1888. While the American-style bars in Europe specialized in what Wondrich calls “very fancy, overwrought fantasias based on American drinks,” Capozzi built a following among the well-heeled upper class and celebrities who vacationed in Monte Carlo by stripping the formality of service and pairing it with a leaner menu of New York–style cocktails, like the Manhattan and Martini. “Ciro was the right man in the right place at the right time. He was personally charming, but also fanatically dedicated to quality, in that Italian way—sprezzatura,” says Wondrich. “He had much more of the Jerry Thomas style, ‘Let me lean on the bar and tell you what you really need, my friend. I don’t care if you’re the Duke of Bedford.’”

Capozzi’s mix of high style and a new informality was codified when he sold his bar and name; from the 1890s through 1950s, a fleet of Ciro’s-branded restaurants spread from London and Paris to cities like Berlin and Los Angeles. Capozzi is just one such example in the book of the fascinating, and often colorful, lives of bartenders who warrant more than a historical footnote. “It all goes back to this little Neapolitan guy who was just a goddamn good bartender,” says Wondrich.