Notorious as Don the Beachcomber’s “lethal libation,” the Zombie cocktail is now part of the classic tiki drink canon, and a mainstay at most modern tiki bars. But the recipe, which is made with myriad “secret ingredients” and a complex blend of rums, has become the source of endless modern tinkering.

Bartender Martin Cate first began seriously working on the Zombie not long after opening his San Francisco bar, Smuggler’s Cove, in 2009. A critical part of his journey was finding the “right” recipe to work from, Cate notes. Thanks to Donn Beach’s penchant for keeping his recipes secret, a wide range of books and tiki experts have taken aim at the iconic drink. Many versions miss the mark. Even tiki legend Trader Vic’s recipe books would specify, “this is our take” on the Beachcomber’s Zombie. “Even [Trader Vic] didn’t know what it was,” Cate laments.

Tiki expert Jeff “Beachbum” Berry’s fieldwork went a long way toward demystifying the drink. In addition to the 1934 version now regarded as the original, which Berry found in a notebook belonging to a Beachcomber bartender named Dick Santiago, he also unearthed a 1950s version. “It’s pretty agreeable, it’s long and boozy and satisfying,” Cate recalls; it was the version served at Forbidden Island in Alameda, where Cate worked prior to opening Smuggler’s Cove. “I’d put them side by side for our guests, the 1950 vs. 1934. People would always walk away with the 1934.”

The 1934 recipe is, per Berry’s findings, a potent mix of rum, lime and grapefruit juices, plus sweeteners including grenadine, falernum and the final mysterious “Spices #4” ingredient—which turned out to be the spiced syrup known as Don’s Mix. It became the recipe on which Cate would base his own version.

Cate began working on the details of the drink, first by splitting up the famed Don’s Mix, a secret blend of grapefruit juice and cinnamon syrup, into its individual components. His recipe relies on a house-made spiced syrup (made with white sugar to provide a “clean expression of cinnamon”) plus a quarter of an ounce of fresh, white or pink grapefruit juice. Those varieties—especially the white grapefruit, when it’s in season—offer a “really bright, vibrant acidity” without extra sweetness, says Cate. Ruby Red, according to Cate, is simply too overpowering, even in small quantities (his recipe calls for a mere quarter-ounce of grapefruit juice). He’s also careful about how the citrus in the drink is juiced: Cate prefers to use an electric reamer rather than a hand juicer for limes, which, he says, results in “good bright oil” from the peel without tannic elements from the pith.

Related Recipe Smuggler's Cove's Zombie Adapted from Donn Beach’s Zombie, Martin Cate’s version of the classic tiki cocktail hews close to tradition. More Recipes →

In typical tiki fashion, the original Zombie recipe calls for three different types of rum, and Cate’s recipe hews close to the original 1934 version, decoded by Berry. He uses a robust aged rum (such as Doorly’s XO or El Dorado 8) for what he calls “the meat of the drink,” plus an oakier, lighter-bodied “lengthening rum” (such as Angostura 7 or Bacardi 8). Finally, a “turbocharged” overproof rum (like Plantation OFTD) adds character and strength to the mix.

Cate splits again from the original with the final addition of an equal-parts mix he’s dubbed “Herbstura.” Whereas the original recipe calls for dashes of both absinthe (or anise liqueur) and Angostura bitters, Cate takes a cue from New Orleans-based rum enthusiast Steve Remsberg, who reportedly spotted the two ingredients mixed together in a single dasher bottle when he frequented Chicago’s Don the Beachcomber outpost during the 1960s.

“[Remsberg] saw the bartenders get tired of mixing drops of Herbsaint and drops of Angostura, and they mixed them into a single bottle,” Cate recounts. “That was an inspiration to us.” In addition, Cate’s taken the mixture a step further, omitting the standard 90-proof Herbsaint in favor of the richer 100-proof Herbsaint Original, which the Sazerac Co. reintroduced to the market in 2009.

Despite these learned tweaks to the recipe, Cate explains that his journey’s not quite over yet. Even today, he continues to tinker with the Zombie, searching for one more ingredient that just might take the drink over the top. “Every drink,” he says, “is an ongoing process.”