French bartender Nico de Soto has a technique that lends cocktails a nuanced note of coffee, but doesn’t require adding coffee, cold brew, espresso or even coffee liqueur. In fact, it’s almost as simple as dropping a coffee bean into a mixing glass.

“It’s very easy,” says de Soto, proprietor of Danico, a near-hidden cocktail lounge that opened in 2016 in Paris’ second arrondissement. He uses this trick in a wide range of stirred-style drinks, because, as he sees it, “Coffee goes with everything.”

He’s stirred whole beans into riffs on classics like the Negroni and Manhattan—usually for a spur-of-the-moment bartender’s choice—adding just a hint of coffee flavor, which harmonizes with similar tones that naturally occur in sweet vermouth or sherry, as well as whiskey or other barrel-aged spirits. Danico’s bar manager Thibault Méquignon drops whole coffee beans into his original Stir it Up, made with 30&40 (a French aperitif spirit made from a blend of pommeau, Calvados and rum), allspice-infused Appleton rum, verjus and a gingerbread reduction, which lend a hint of weight and depth.

Often, because the beans are strained out‚ discarded and rarely mentioned as part of a drink’s anatomy, it can be difficult for a customer to pin down the subtle, yet memorable, flavor. And yet, it’s a refreshing, light-handed way to work with a robust ingredient that frankly, can be a bully in cocktails. While coffee is meant to be front and center in an Espresso Martini or the current wave of cold brew–infused cocktails, a Martinez or a Perfect Martini (made with equal parts dry and sweet vermouth) requires a softer touch to remain true to the canon, while still adding a hint of originality.

Despite de Soto’s breezy explanation, make no mistake: There’s thought behind this pro move. He specifies dark-roasted coffee beans (preferably French roast) for this hack. A longer roast results in a more intense caramel or chocolate-like flavor, while also coaxing more oil from the bean. Says de Soto: “More oil, more flavor.”

Of course, the technique has limitations. Because the flavor is subtle, and oils from fresh beans can dissipate, the fleeting notes can be lost when mingled with sharp or bitter flavors like Fernet, overproof spirits or even the bright acidity of citrus juices—one more reason it’s a hack best saved for stirred drinks rather than shaken. And of course, this technique wouldn’t be used in a coffee-based drink, where the effect would be negligible.

De Soto doesn’t recall the precise catalyst for experimenting with the coffee bean trick. In fact, he insists it was an intuitive move anyone might have made, “like putting salt in food.