Summer is the perfect time to sip on a gin and tonic: not only is it incredibly easy to make, there's something about it that pairs perfectly with hot weather. But that hot weather connection may not be a coincidence, either: the cocktail was first drunk by British soldiers looking for a palatable way to prevent malaria. As André and Tenaya Darlington, the sibling duo behind The New Cocktail Hour, explain to Refinery29, the ingredient that gives tonic its signature bitter flavor is quinine, a kind of bark that was first used to treat malaria in the 16th century.
Later, British soldiers would drink the quinine in water, thus inventing tonic water. They soon discovered that tonic pairs well with gin, and thus, the G&T was born. "You take something herbaceous like gin and mix it with something bitter and slightly sweet like tonic, then you add your citrus and you get this perfectly balanced drink," explains Tenaya. Today, we drink tonic water for the taste, not for the antimalarial affects, though all tonic water still contains quinine.
That doesn't mean that all tonic is created equal, however. In addition to quinine, inexpensive tonic water often includes corn syrup as well as artificial flavors. Until recently, unless you made your own tonic syrup, that was about all you could buy. Then premium tonics started popping up on the market, giving this easy cocktail an even easier upgrade. The Darlingtons played around with different options while writing their book, and found that one of the first brands on the market, Fever Tree, to be their favorite — a plus, because it's also one of the most widely available.
If you really want to get fancy, you can even make or buy your own tonic syrup, allowing you to play with just how much tonic flavor is each drink. There are lots of recipes floating around online, but if you just want to let someone else do the work, the Darlingtons recommends Jack Rudy tonic syrup, which typically retails anywhere from $15-20 but can sit in the fridge and be added to seltzer water whenever you want, reducing the chances that extra tonic water will go to waste. Especially if you have your own SodaStream, you can make exactly the amount of tonic water you need with no waste.
Another mixer that the Darlingtons don't skimp on? Soda water. Originally made to be an inexpensive alternative to mineral water, which is also naturally bubbly, it's force-carbonated with ingredients like sodium and calcium added for flavor. André and Tenaya tried a number of soda, mineral, and seltzer waters in a classic mojito recipe to see what they preferred and, not surprisingly, found that the real thing came out on top. Their mineral water of choice is Perrier, finding that it added a "really fine prickle" to the drink that set it apart from regular soda water. They also prefer that mineral water be added as a final splash (like in a mojito or Tom Collins, another classic soda water drink), rather than mixed more heavily. Unlike tonic water, there just isn't enough flavor going on to really be mixing it in a bigger ratio to the booze.
When it comes to regular seltzer, however, they skip using it as a mixer. "Drink seltzer if you’re just drinking to hydrate," says André. Otherwise, they recommend just keeping some nice tonic water or syrup and small bottles of a natural mineral water on hand, and you'll be ready to mix up a craft cocktail (and maybe ward off some mosquitos) whenever the craving strikes.