What Are the Differences Between Tonic, Soda Water, and Seltzer?

Imagine: It’s the time of day when you start to craze a Gin and Tonic. Not just any Gin and Tonic, but a homemade Gin and Tonic, because you don’t want to leave the house. You have the gin (naturally), and the lime, but you somehow don’t have the tonic. So you decide to improvise with some seltzer or soda water. It’s all the same thing anyway, right?

Wrong. Don’t do that. Suck it up, go outside and buy some tonic. Because while all three drinks are bubbly and perfect for cocktails of some kind, they are not interchangeable. Here’s how each is different, starting with their basic definitions from Dictionary.com.

Tonic

Tonic (see quinine water) is carbonated water containing lemon, lime, sweetener, and quinine, often used as a mixer.

The origin of tonic starts in the mid-1600s in Peru. A member of the Spanish ruling class at the time came down with malaria, and they turned to the local Inca people for help. The Inca suggested a potion — a “tonic,” if you will — made with ground up bark from the native quinquina tree. It worked, and after being cured, the Spanish proceeded to destroy the indigenous population.

Fast-forward to the 1800s and British soldiers. They were downing quinquina as an anti-malaria medicine like no other. The only problem was the awful bitterness of the stuff. So they added soda water, sugar, and gin. The popularity of tonic and the Gin and Tonic exploded from there.

Soda Water

Soda water is an effervescent beverage consisting of water charged with carbon dioxide.

Soda water was invented by Joseph Priestley, the same person who discovered oxygen. It’s fair to say he had some pretty good ideas bubble up in his lifetime.

Priestley, inspired by the natural carbonation from beer and Champagne, isolated carbon dioxide and figured out how to put it into water. Voilà: soda water, a.k.a carbonated water, a.k.a regular water with bubbles. He won the Royal Society’s Copley Prize — the world’s oldest scientific prize — for his carbonated water.

Seltzer is a naturally effervescent mineral water containing common salt and small quantities of sodium, calcium, and magnesium carbonates.

If you live in Brooklyn, you’d be forgiven for thinking that LaCroix recently invented seltzer and the sparkling drink in general is some hot new invented trend. It’s not. There’s a whole book on the history and culture of seltzer by Barry Joseph called “Seltzertopia: The Effervescent Age.” In it, he talks about the spas in the German town Niederselters in the 1700s. Niederselters bottled the bubbly from their spa and sent it around the world. Americans got lazy with the town name and shortened it to seltzer.