What Is A Coffee Tonic, Anyway?

Maybe you got too caught up in colorful cans of LaCroix to notice, but over the summer, at cafes al over the country, Instagram snaps of what might have otherwise have been latte art were replaced, now and again, by some … bubbly, layered beverage in a plastic cup.

Yeah, what were those? Tan and foamy on top, mysteriously dark in the middle, clear and effervescent on bottom.

We saw it at Cartel. We saw it at Futuro. We saw it at Kream and at Peixoto.

These were clearly no boring cups of cold brew.

As the name suggests, it’s simple: a “coffee tonic;” iced, sparkling tonic water with a shot of espresso layered — not splashed — over top. You have to do it slowly; the copper-colored layer of bubbles sitting on the espresso, called “crema,” is volatile CO2 and since too much friction with fizzy water can result in quite a mess, baristas take it slow.

If you can consider a soda a soft drink that’s been carbonated, flavored, sweetened, and served cold, then you can view the coffee tonic for what it is: a coffee soda, albeit a freshly made one. Given the prominent role that the concentrated coffee plays in the beverage, this drink has really only gotten popular within the specialty coffee sector, where shops tend to pay a greater attention to the flavor of espresso.

Tonic water is pretty sweet, thanks to a good amount of added sugar, but it’s there to balance the beverage’s bittering agent, called quinine; the same stuff that lends pleasant bitter quality to your Italian liqueurs.

Some shops like Futuro put their tonic trust in a proven brand. In that shop's case, Fever Tree, the standard bearer as of now for the tonic industry — if you asked for a gin and tonic at a craft cocktail bar, they’re probably using Fever Tree. A few widely distributed craft brands like Q are now available as well. Either way, most brands will deliver a neutral flavor that lets the complex flavors in a quality, nicely pulled shot of espresso shine, just as it would let an interesting and nuanced gin. There’s a locally made tonic mixer, too, made by Iconic Cocktail Co, which is flavored with kaffir lime.

Cartel flavored theirs, when they had it (it’s not currently on the menu; it may come back). It was simply tonic water, espresso, with a smidge of vanilla bean paste dotted in.

“We felt the vanilla bean paste helped to make it a bit rounder and accentuate the complex character of the espresso,” says Amanda Cohen, Cartel Coffee Lab’s director of education and quality control. Kream coffee, by contrast, squeezes citrus in theirs to amplify the acidity already present in espresso and the tangy flavor of the quinine.

The most from-scratch end of the coffee tonic spectrum is represented by the folks over at Peixoto, in Chandler. They make their own tonic syrup from start to finish, and add in flavors they feel will compliment the type of espresso. A formula of quinine, citric acid, and sweeter can turn into, for instance, a tonic syrup flavored with ginger and lime, and sweetened with agave. The shop currently offers this variety. They add soda water to the syrup and float the espresso atop. This approach appeals to Kimhak Em, who develops recipes and oversees quality control at the shop and has a background in culinary school. He wanted to put a culinary spin on a drink that’s been trending in coffee shops around the nation.

“I think the first time I had an espresso tonic was at one of the shops that I frequented in the Bay Area,” Em says. That was close to two years ago.

The drink hasn’t existed all that long — it began at a very prominent coffee shop and roaster in Sweden called Koppi. When a coffee shop called Saint Frank opened in San Francisco in late 2013, they paid homage to Koppi’s drink, making their own version — still just Fever Tree tonic, ice, and espresso — called the Kaffe Tonic (kaffe being the Swedish word for coffee). As Saint Frank rose to prominence in eyes of coffee professionals across the country, shops began adopting their own version, some sticking to the drink’s paired down roots, and others opting to personalize.

Three years later, it looks like the drink has stuck.

Editor's Note: Shelby Moore works with Futuro in various capacities.