As a seasoned Martini drinker, I always have my favorite call at the ready when a bartender asks: Gin or vodka? Vermouth? What ratio? Olive or twist? Occasionally, I’ll get a final inquiry: Would you like bitters in that? 

The question is often posed as an afterthought, so in turn, I usually end up viewing the ingredient as such. Out of sight, out of Martini glass. And I’m not alone in this—after searching through contemporary cocktail menus and chatting with an array of bartenders around the country, it’s clear that bitters have not secured a definitive role in the modern Martini.

Rewind to the drink’s original heyday, however, and bitters were a requisite ingredient in the Martini formula. In a survey of more than 40 texts printed between 1888 and 1949, almost every historic spec included a few dashes of either orange or Angostura bitters, with the earliest recipes calling for Boker’s (which went out of production in the 1920s). How did the once-critical ingredient become relegated to awkward third-wheel status? 

In part, Prohibition is to blame. “There were very few bitters brands still standing after Repeal, including Angostura and Peychaud’s,” says cocktail historian Robert Simonson, author of The Martini Cocktail. “If you’re a bartender and you simply can’t find orange bitters, you’re going to leave it out of a Martini. Because it’s not as if people are going to stop ordering Martinis.” 

After Prohibition, bartending became “a workaday job, not the star profession it was in the 19th century,” Simonson adds. “As a result, drinks became simpler.” In the 1940s and ’50s, the classic three-ingredient framework almost disappeared in favor of bitters-less Martinis on the rocks, ones made with olive brine and, eventually, vodka Martinis.

It wasn’t until the cocktail revival of the early aughts, when curious bartenders started rooting around in vintage cocktail books for inspiration, that the Martini in its full classic glory—bitters included—came roaring back into fashion. “We all came to realize that the definition of a cocktail, as set down in 1806, was a drink that contained bitters,” explains Simonson. “If a Martini was a cocktail, as indeed it was, that meant it should have bitters in it, and research into the drink bore that truth out.”

Audrey Saunders—a self-professed “drink nerd from Day One of my career”—was one of the first to resurrect the proper Martini, bitters and all, when she opened New York’s Pegu Club in 2005. “My goal with my Fitty-Fitty Martini was to get folks drinking both gin and vermouth again, as well as bring the dry Martini full circle and back to its roots,” she says. At the time, only Angostura, Fee Brothers and Regans’ orange bitters were available in New York City. To best match her gin and vermouth of choice, she took matters into her own hands, mixing an equal-parts blend of Regans’ and Fee Brothers’ orange bitters—a utilitarian combo that many bar programs later adopted, using the moniker “Feegans.” This new wave of interest in aromatic bitters helped spur renewed consideration for the ingredient’s role in Martinis in bars beyond Pegu Club.

Yet, here we are again in a cocktail landscape where bitters are omitted from the Martini as often as they’re included. For William Elliott, longtime bar director at Maison Premiere, this trend reflects the prevailing ethos of the day: There’s no right or wrong way to make a classic cocktail. “There are times when I love bitters in Martinis and there are some times when I’m not so into them,” he says. Orange bitters are necessary to bring dimension and depth to his famously bone-dry Old King Cole Martini because they essentially mark “the difference between frozen gin and a composed cocktail,” he says. But at the new Lower East Side cocktail lounge Tigre, where he is also the bar director, the bitters are optional. “In this new age of Martini obsession, and dare I say renaissance, the coolest thing to do is to make the simplest, most basic Martini, but make it highly customizable and personal.”

That’s where the bitters come back into play. For a growing number of bars, bitters are the perfect tool for Martini customization: They do not steer the drink away from the classic blueprint, and with countless expressions on the market, they enable nearly infinite experimentation. At Kumiko in Chicago, Julia Momosé’s signature Martini features The Japanese Bitters yuzu bitters as a way to strengthen the drink’s connection to Japan. At New York’s Overstory, orange bitters are always used to signal the classic nature of the house build. At Atlas in Singapore, meanwhile, chocolate bitters bring warmth to the floral Orange Blossom Martini, which features St. George gin made exclusively for the bar. “Bitters can be a versatile ingredient for customization, allowing a bartender to tailor drinks to specific themes, occasions or even individual preferences,” says head bartender Yana Keller.

Indeed, individual preference is the primary motivation behind the Connaught Bar’s approach to bitters in the Martini. At the London bar, the tableside house Martini service features a rolling trolley complete with options for gin or vodka, a bottle of the bar’s custom vermouth blend and five dropper bottles of housemade bitters, including dry lavender, coriander, tonka bean, black cardamom and Dr. Ago’s (a mix of ginseng and bergamot). 

In the upcoming Connaught Bar Book, director of mixology Agostino Perrone explains that offering a selection of bitters is simply a reflection of the bar’s approach to hospitality. The decision regarding whether bitters make a Martini better or not—and if so, which type—is in the hands of the drinker. As Perrone says, “The truth is, the addition of bitters to this simple sip of gin and vermouth is the ideal place to add your personal touch, to create a Martini cocktail of your very own.”