Why Coffee Tonic Might Replace Your Favorite Cold Brew

The refreshing gin and tonic is clearly a warm-weather classic, but there's no reason why gin, or cocktails for that matter, should have all the sunny season fun. Tonic water is also the perfect carbonated sidekick for the coffee tonic and the espresso tonic, alcohol-free, thirst-quenching quaffs that emerged in the early aughts and are once again generating buzz. We connected with coffee and beverage experts to discover why this drink trend is picking up steam—and learned a few tricks for stirring up both at home.

What Is a Coffee Tonic?

As every Joe lover knows, coffee can be made into countless drinks, from lattes to iced cappuccinos. The coffee tonic, combining cold brew and tonic water—and the espresso tonic, uniting espresso and tonic water—widen the chilled options. Still, they are also a bit of a departure.

It's a cold sipper: "The espresso tonic is a refreshing and enlivening drink on those hot summer days," says Matt Falber, founder of City Boy Coffee.

It's a cocktail alternative:  "Every summer, we see people get creative with coffee mocktails," says Caroline Bell, co-founder and co-owner of Cafe Grumpy. "Espresso tonics are just one of the many things you can make." Falber likens the drink to a beloved Italian aperitif. "To me, it is to coffee what the Aperol spritz is to alcohol." He adds that the quinine—a core ingredient in tonic water—is slightly bitter and citrusy, somewhat like Aperol.

It's delicate: The espresso tonic and the coffee tonic are lighter than their chilled cousins, iced coffee and cold brew; plus, they're fizzy. "It's half the caffeine, yet it also helps to hydrate you," says Mary Pellettieri, co-founder of Top Note. "You can drink it any time of the day, especially when you're looking for a boost."

Why It Works

The coffee tonic and the espresso tonic both have just two ingredients, so each must be top-notch. The magic happens once they're combined. "Most people are familiar with the flavors but just don't recognize them as a pair," says Pellettieri.

Taste: The components mesh beautifully. "Orange peel or grapefruit peel and chocolate can make fast friends," Pellettieri says. "A modern tonic water will have the citrus and tartness of a peel, and coffee will have the round, chocolate, and sweet notes."

Balance: Coffee is naturally high in acid, Pellettieri adds, so it should be balanced with a lower-acid tonic like Indian tonic water.

Bitter—or bittersweet: The ingredients also share common ground. "The bitterness in coffee and tonic cancel each other out and are often not a factor," says Pellettieri. Still, for some, that flavor requires a touch of tinkering. "Since the tonic and espresso together can be a little bitter for everyone's taste, we like to add sugar and citrus or sub a flavored seltzer for the tonic to keep the effervescence of the drink," says Bell.

How to Make a Coffee Tonic

When deciding which java beverage to make at home, you may be swayed by personal preference—or the equipment available. "If you don't have an espresso machine, you can use cold brew (easy to make at home and super versatile) in place of espresso in your favorite coffee drink," says Bell.

Cold brew is much easier to mix and is how we suggest starting, adds Pellettieri. Here's her take on coffee tonics:

1. A 50/50 ratio of cold brew to tonic water is usually perfect.
2. This ratio, she adds, cuts the caffeine in half and is easier to drink.
3. The extra small solids from the coffee extraction in the cold brew can make it foamy, so allow for extra headspace. "The foam is a thing, so enjoy that!" she says.

Falber finds that cold brew isn't intense enough. He uses cold brew concentrate.

How to Make an Espresso Tonic

The proportions of this drink may hinge on your individual leanings. Here's Falber's formula:

1. Use one part espresso to four parts tonic water, says Falber.
2. Mix it with a spoon in a separate container and pour it into a serving glass.
3. Leave the carbonated head in the serving glass; it will start to fall in quickly.
   

Alternative measurements and method: Pellettieri's recipe combines one part espresso with two parts tonic (or more). The espresso is floated on top of the tonic. This is a bit more tricky in terms of both flavor and presentation and is how many pros make the drink, she says.

Final flourish: A lemon twist, Falber says, is a great garnish, but he doesn't add anything else. "Avoid milk or alternative milk," he says. "Think Aperol spritz, think gin and tonic. You wouldn't want milk in those; don't add it to this."

Trend or Mainstay?

Time will tell whether the coffee tonic is a passing fancy, a trend with legs, or a bona fide classic.

Enduring trend:  To Pellettieri, the drink has staying power; she says it has been a staple at cafes since first emerging in Oslo, Sweden, in 2007. "Americans still find it to be new and novel, but so was the espresso martini at one time!" Given the espresso martini's popularity, the espresso tonic seems destined for lounge menus. It's a simple, non-alcoholic cocktail-like drink that any bar can make, she says.

Resurgence-ready: Beverages tend to fall in and out of favor, says Falber. "It could become a mainstay, or, more likely, it will become less popular, only to make a comeback at some point," he predicts.

Next up: As the mercury rises, other cold sippers will join the party. “This summer, we are drinking cold brew over natural coconut water and ice for a healthy and hydrating pick-me-up," says Bell.