The classy lavender tonic is a zero-proof blend of bitter and sweet

The word “tonic” is defined as something promoting vim, vigor and vitality — a refreshing remedy, a cure for what ails ya, a potable that puts the pep firmly back in your step. That’s precisely the sort of thing tonic water excels at, even if it’s better known as a second fiddle for spirits.

But alcohol isn’t necessary to enjoy everything it has to offer. A bubbly blend of bitter and sweet, tonic water can turn just about anything into an instant adult beverage. It’s also perfectly delightful on its own.

Originally, tonic water was intended for saving lives, not making cocktails. Though today we know malaria as a tropical disease, before the discovery of quinine — a bracingly bitter compound extracted from South American cinchona bark — it could be found anywhere where mosquitoes thrived, which was pretty much everywhere. For centuries, malaria was treated with questionable methods that included the application of pickled herrings to the feet as well as eating cobwebs, neither of which proved effective nor tasty.

Quinine, though effective, also tastes pretty terrible on its own, which is why it has often been mixed with similarly aggressive (yet far more palatable) drinks — such as wine, spirits and even coffee — to make the medicine go down. “Real quinine is like a fresh piece of Scotch tape,” says Faith Dionne, founder of craft producer Dappled Tonic. “It will lift the cat hair right off a sweater.”

While we’re not sure exactly when people started mixing it with sugar and carbonated water, we do know the first commercially available tonic water was patented in England in 1858. Pitt’s Aerated Tonic Water claimed its carbonated quinine could ease a variety of ailments: “it gives strength to the stomach and tone to the whole nervous system, and is especially adapted to persons feeling depressed from mental or bodily excitement, imparting strength to those who suffer from nervous irritation, indigestion, or loss of appetite.”

Regardless of its medical bona fides, tonic water would have likely gone the way of most other 19th-century snake-oil remedies had it not been for its popularity with officers of the imperial British army. Quinine was administered prophylactically to soldiers as the empire colonized muggy, malaria-plagued areas in Africa and southern Asia. The enlisted men found that quinine’s violently astringent bitterness, once watered down, melded marvelously with gin.

Fast-forward to the 1920s, when cocktail culture exploded and, under American Prohibition, mixers were needed to enhance (and, occasionally, cover up) the taste of bathtub gin. Tonic water made the leap from the medicine cabinet to the back of the bar, and has resided there ever since. But that doesn’t mean it belongs only with booze.

Personally, I enjoy drinking tonic water straight out of the can, especially now that there’s a number of stellar smaller brands — such as Top Note, Chuala and the aforementioned Dappled — that stand head and shoulders above the high-fructose-corn-syrup-sweetened sodas in plastic bottles or a bar’s beverage gun. And when I’m in the mood for a nonalcoholic nightcap with minimal effort, tonic is the first thing I reach for.

Just as adding carbonated water turns just about any liquid (Within reason! Yes to OJ, no to mouthwash.) into a soda, tonic water’s bitter bubbles can transform any drink into a cocktail. “Where tonic water is different from seltzer is that it hits all the points,” says Dionne. “Seltzer happens and tonic water IS HAPPENING.”

When she’s not designing bespoke zero-proof cocktails for bars and restaurants, Laura Silverman of Zero Proof Nation uses tonic as the base for “nearly all” of her at-home cocktails, saying “it adds more depth and a punched-up flavor than just regular soda water.” If you’ve got a bottle of novel nonalcoholic spirits you’re not sure what to do with — especially anything heavily botanical from brands such as Ghia, Tilden, Vera or Wilderton — adding tonic water will keep things simple and sophisticated, allowing you to appreciate the base’s unique qualities while adding a little something extra.

If you’d like to try tonic’s transformative powers for yourself — no bar cart required — I’ve got just the thing. This lavender-honey tonic is soft and floral, with just enough bitterness to keep it grown-up and to prevent it from tipping into fussy cocktail territory — the kind of drink that makes weeknights feel like an occasion. A quick steep of dried lavender gives the syrup a soothing foundation, honey rounds it out with a mellow sweetness, and tonic water snaps everything to attention. It’s refreshing, elegant and nonalcoholic, proof that sometimes the best nightcap is the one that keeps you clearheaded.

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Lavender Tonic

1 lemon, halved

1 cup boiling water

2 tablespoons dried or fresh culinary lavender buds*

¼ cup honey

Ice

Tonic water, to top

Squeeze one of the lemon halves to yield 1 tablespoon of juice. Slice the other lemon half to get two wheels.

In a liquid measuring cup with a spout, combine the boiling water with the lavender and let steep for 5 minutes. Stir in the honey and lemon juice until the honey dissolves. Let cool completely, then strain into a bottle or jar. You should have about 1¼ cups. Refrigerate until chilled, at least 1 hour.

Fill two highball glasses with ice and add 6 tablespoons (3 ounces) of the lavender syrup to each glass. Top each with tonic water, garnish with a lemon wheel and serve.

Servings: 2 (makes 2 drinks)

Make ahead: The lavender syrup can be made up to 5 days in advance.

*Where to buy: Dried culinary lavender can be found at specialty shops, natural food markets and online.

Substitutions: For lemon, use orange or clementine.

Nutritional Facts per drink, using 4 ounces tonic water | Calories: 82. Fat: 0 g, Saturated Fat: 0 g, Carbohydrates: 22 g, Sodium: 15 mg, Cholesterol: 0 mg, Protein: 0 g, Fiber: 0 g, Sugar: 22 g

— Allison Robicelli