What should you use when a recipe calls for soda water?

Many cocktail recipes call for a splash of soda water. Most people will use their preferred brand of club soda or non-sweetened sparkling water. But are these substances interchangeable? And what’s the difference between them, seltzer, and tonic? Over at Epicurious, Matt Duckor explains that these effervescent products are similar but that there are some notable differences between them. 

Duckor starts off with seltzer water, which consists of spring water with added carbon dioxide. It has no added flavor and no calories. You can easily make seltzer water with a Soda Stream or similar device at home for pennies. Mineral water is almost indistinguishable from seltzer, except that its bubbles are produced naturally as the water travels over rocks containing salts and sulphur compounds. Since it is usually bottled at the source, mineral water is generally more expensive than seltzer. Club soda, while similar to the above products, although it starts off life as plain tap water, to which chemicals like potassium-bicarbonate and potassium-sulfate are added to provide bubbles and a whisper of saltiness. 

The odd man out in the lineup is tonic water, which is an entirely different beast. Tonic water is sweetened and contains quinine, a bitter-tasting compound derived from the bark of the cinchona tree. You can purchase the bark to make your own homemade tonic water. One thing to note about tonic water: in rare cases, people have suddenly developed a severe allergic reaction to quinine. 

Photo of Bombay fizz  from  Martha Stewart Living Magazine by Charlotte March.