Tonic water is a carbonated drink that contains a compound called quinine that creates its signature bitter taste. Manufacturers often add sugar to the drink to balance this bitterness, giving it a bitter and sweet taste, sometimes described as a citrus flavor. Originally a medicinal drink that medical professionals offered soldiers to help treat malaria, tonic water became popular for its flavor and is now a widespread ingredient for several mixed drinks, most notably the [Gin and Tonic](https://www.masterclass.com/articles/classic-gin-and-tonic-recipe). \nClub soda is carbonated water that contains additional minerals, like disodium phosphate, potassium sulfate, sodium bicarbonate, or sodium chloride. These minerals give the drink a mild, slightly salty taste, similar to mineral water. Club soda is a common ingredient in many cocktails, like the [Tom Collins](https://www.masterclass.com/articles/how-to-make-a-tom-collins) and the [Mojito](https://www.masterclass.com/articles/how-to-make-a-mojito).\n\nClub soda is closely related to other types of bubbly water, especially sparkling mineral water, which has natural spring carbonation. It is also similar to mineral-free carbonated water drinks like sparkling water, soda water, or seltzer water. Substituting any of these drinks for club soda will produce a similar final result, so many mixologists use them interchangeably. \nTonic water and club soda are two types of carbonated water that bartenders use to mix cocktails, but there are a few differences between the beverages:\n\n- __Additives__: While tonic water and club soda feature dissolved carbon dioxide to create their characteristic fizz, manufacturers add other ingredients to the beverages to create their signature tastes. Tonic manufacturers add quinine—a bitter compound from the bark of cinchona trees that doubles as an antimalarial treatment—to the drink and often use sugar to counteract the bitterness. Club soda manufacturers add minerals to the drink that mimic the natural minerals and slightly salty flavor of mineral water. \n- __Flavor__: The biggest difference between tonic water and club soda is the taste. Tonic water has a strong bitter and sweet flavor, while club soda has a mild, faintly salty flavor. \n- __Nutritional content__: Since tonic water contains added sweeteners, like sugar or high-fructose corn syrup, and calories, it falls under the soft drink category. Plain club soda has the same nutrient profile as plain water and usually contains zero calories and zero sugar. Diet tonic waters may feature a diet sweetener like aspartame that contains no calories.\n- __Uses__: While tonic water and club soda are both ingredients that mixologists use to add a bubbly mouthfeel to a cocktail, their vastly different flavor profiles contribute different tastes to a drink. Hence, bartenders rarely substitute one for the other. Tonic water can add strong bitterness and sweetness to liquor and isn’t usually accompanied by many other flavored ingredients. On the other hand, club soda has a mild flavor and adds a unique mouthfeel to a drink with other flavorful ingredients. \nLearn more about mixology from award-winning bartenders. Refine your palate, explore the world of spirits, and shake up the perfect cocktail for your next gathering with the [MasterClass Annual Membership](https://www.masterclass.com/). \nTonic water and club soda are two carbonated beverages with very different uses as cocktail mixers.