The Martini is one of the world’s most popular cocktails, likely due to the sheer number of ways the cocktail can be enjoyed. It can be based on gin or vodka (or neither, if you’re thinking outside of the box) and flavored with vermouth, olive brine, or something else entirely. It can be shaken, stirred, or even served on the rocks, and that’s just the beginning. Beyond these fairly standard Martini requests, there are also myriad ways to communicate a specific way you’d like your cocktail served.

You can request it naked — which, somewhat shockingly, does not refer to a lack of garnish — though maybe you prefer your ‘tinis made to skate. But there’s one Martini call that refers just to the amount of vermouth used and how it should be incorporated into the cocktail: in and out. But what exactly does it mean to order a Martini as such? VinePair spoke with Kate Sikora, head bartender at Hawksmoor Chicago, to find out.

“An ‘in and out’ Martini is a chilled or frozen spirit with a vermouth rinse,” she explains. “I believe it’s called ‘in and out’ because the dry vermouth is simply in, and then out, of the glass.”

According to Sikora, this style of Martini had a surge in popularity in the late 1960s as it was President Richard Nixon’s preferred Martini style. While it’s fairly common today to serve in and out Martinis by rinsing the glass itself, Nixon allegedly preferred his made in a slightly different manner. He first liked the vermouth to be shaken with ice in a cocktail shaker then dumped before gin was added, reshaken with fresh ice, and strained into a chilled cocktail glass. He was even rumored to have been drinking one of these Martinis the night he resigned over the Watergate scandal.

Considering their popularity in the late ’60s and early ’70s, Sikora doesn’t often hear calls for in and out Martinis. “I get one maybe once every two weeks, and it tends to be an older demographic that orders it,” she says.

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While it might be a drink tied to an older generation of drinkers, the cocktail did experience somewhat of a revival in 2018 when “A Simple Favor” was released, perhaps making it more recognizable among younger drinkers. In the film, Blake Lively’s Emily Nelson character claims an in and out Martini is a “real Martini” before walking Anna Kendrick’s Stephanie Smothers through the process of making one. In goes the vermouth, around it goes in the glass, and out it pours before frozen gin enters the glass.

As Sikora explains, the request for an in and out Martini is almost always tied to calls for gin Martinis — and it’s almost always dry vermouth used to build the spec.

“I typically only use about one-quarter- to one-half-ounce of dry vermouth per rinse, and yes, dry vermouth is usually used in this situation,” she says. “I have never had a request for another type of vermouth, but I would be open to it.”