What Is Tonic Water? How It Differs From Seltzer and Club Soda

Tonic water is a classic bar mixer that is beloved for its bubbles and bittersweet taste. The drink has changed over its 150-plus year history and is now crafted in blends to give traditional cocktails, like gin and tonic, a modern update. Learn from our expert exactly what tonic water is and why this essential bar ingredient adds flavor to everything from hard liquor to mocktails.

What Is Tonic Water?

Tonic water is a carbonated drink, often used as a mixer for cocktails but is often consumed by itself without anything added. It is best known for the inclusion of small amounts of bitter quinine among its ingredients.

What Does Tonic Water Taste Like?

The distinctive taste of tonic water is based on the range of flavors in its ingredients, which include citric acid, sweetener—often high fructose corn syrup—carbonated water, natural flavors, and quinine. The result is a little bit sharp and sugary. "Tonic water tastes slightly bitter, with a hint of sweetness and a citrus flavor," says Jason Hedges, a bartender and the author of The Seasonal Cocktail.

Tonic Water vs. Club Soda vs. Seltzer

Tonic water, club soda, and seltzer are all versions of carbonated water, though they don't taste the same.

• Tonic water provides a unique flavor profile. It can contain sugar, citrus, and other botanicals, says Hedges.
• Club soda is made with carbon dioxide, but it also includes mineral salts and sometimes sodium bicarbonate which gives it slightly more body and a bit of a saltier taste. "Seltzer and club soda are often used as mixers for non-alcoholic drinks, or as a base for other flavored syrups," says Hedges.
• Seltzer contains carbon dioxide only, which is what makes it fizzy.
  

Trends in Tonic Water

Modern tonics are interesting and tasty—even without the addition of alcohol. "Newer tonic water brands often feature more unique flavor profiles and use natural sweeteners rather than high fructose corn syrup," says Hedges. "A more expensive tonic water may be of higher quality and offer a more complex flavor, but this is not always the case. It ultimately comes down to personal preference and the ingredients used."

Some brands may eliminate corn syrup to lower the calorie and carbohydrate counts. Other brands offer a light, lower-calorie option, as well as types featuring notes of elderberry, lemon thyme, cucumber, hibiscus, grapefruit, or vanilla. Other unique options may include notes of honeybush (an aromatic shrub), marula (a tree fruit), yuzu (a citrus fruit), or agave.

Ways to Use Tonic Water

Drink tonic water without alcohol by adding a splash of cranberry juice and a wedge of lime. Or squeeze an orange or grapefruit slice into the tonic. Try a refreshing tonic with a cucumber slice or sprig of mint floating in the glass.

However, tonic water is famous for its role in gin and tonic or vodka tonic drinks. It also pairs well with other hard liquors and mocktails, says Hedges. Try these other alcohol-based tonic water recipes:

• Rum: Add tonic water with rum and lime juice.
• Tequila: Add tonic water with tequila and grapefruit juice.
• Mezcal: Mix tonic water with mezcal and lime juice.
• Amaro spritz: Blend tonic water with Campari or Aperol for a lower-alcohol version of the Aperol spritz.
• Lillet-basil cocktail: Add a splash of tonic water to this wine-based aperitif for a little fizz.
• Portofino cocktail: Mix tonic water, grapefruit juice, and Campari for a light and summery drink.