What’s the Difference Between Club Soda, Seltzer Water, and Tonic Water?

They're all clear and bubbly and mix well with other beverages, but don't get them confused.

sparklingwaterSyda Productions/ShutterstockWalking through the water aisle of the grocery store, you’ll find various styles of water: flavored, sparkling, bubbly, and so on. Three of the most misunderstood of the water drinks include club soda, seltzer water, and tonic water. Though seemingly the same minus their name at first glance, there are some big differences that separate them.

Each one of these beverages starts with carbonated water, so the difference lies in what’s added, according to Dave Stolte, the author of the illustrated, pocket-sized guide for the home bartending enthusiast called Home Bar Basics (and Not-So-Basics). “Seltzer is just water, club soda contains sodium, and tonic water contains a ‘tonic’ blend (typically a mix of quinine derived from cinchona bark, other roots, and spices, and sometimes sugar and sodium),” he says.

All three of these types of water can be made at home, but Stolte says seltzer is the easiest. “I prefer the iSi Soda Siphon loaded with cold tap water. Enterprising bartenders sometimes make their own tonic syrup to add to seltzer, or use a commercial product like Small Hand Foods’ Yeoman Tonic Syrup.”

As for taste, all three provide a hint of tartness to the water, thanks to the zap of carbonic acid they’re graced with during the carbonation process. “Club soda, with its added sodium, enhances flavors the same way salt on your dinner does,” says Stolte. “And tonic water adds a pleasant earthy bitterness and spice.”

Seltzer and club soda are popular drink-alone flat water alternatives, but all three are majors in the cocktail world. “Seltzer is my go-to for a refreshing Tom Collins or Mojito,” says Stolte. “Club soda is typically added to simple highballs (think Scotch & Soda).”

When you think of tonic, a classic Gin and Tonic likely comes to mind. “Tonic water contains small amounts of quinine and usually sugar,” says Jane Peyton, drinks educator, writer and founder of School of Booze. “Quinine is a very bitter medicinal compound sourced from the bark of the fever tree. It was used by British colonialists in 19th century India to prevent malaria. To make it more palatable they mixed it with sugar and carbonated water. Some genius mixed it with gin and lo, the world’s most popular cocktail was born.”

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