What Is the Difference Between Tonic and Seltzer?

by Cristina Garcia ; Updated September 28, 2017

Tonic and seltzer water are both colorless.

glass with tonic image by Agb from Fotolia.com

Seltzer and tonic water are both carbonated drinks. The process of carbonation is as simple as infusing natural or spring water with carbon dioxide, resulting in a fizzy drink. Seltzer and tonic water are consumed either on their own or mixed in cocktails.

Seltzer Water

Also known as fizzy water or sparkling water, seltzer water is simply plain natural or spring water that has been carbonated. It was invented by Joseph Priestley in 1767 while working at a brewery in England. Seltzer water is tasteless, but is used to give a little snap and sharpness to fruit juices, making the resulting drink a healthier alternative to sodas, which contain sugar, preservatives and artificial colorings. Seltzer water can be made at home with a home carbonation system.

Tonic Water

Tonic water was invented in the 18th century by the British East India Company in India when British expatriates found a more palatable way to take quinine, an anti-malarial medicine. It was mixed with carbonated water, sugar and gin. Taking considerable amounts of the old tonic water for a short period of time could suppress malaria parasites.
Since modern tonic water has less quinine, its bitter taste is only mild. Nevertheless, some types of tonic water are sweetened. In fact, many doctors recommend drinking tonic water regularly while visiting malaria-infected countries as an extra precaution against the disease.

Health Considerations of Seltzer Water

Because seltzer water does not contain sugar, it can be consumed by diabetics and children just like plain water, or mixed with natural unsweetened flavorings or unsweetened fruit juices. Since seltzer is just carbonated water, it can be used as a way of keeping hydrated without worrying about health risk of consuming additives, sugars and preservatives.

Health Considerations of Tonic Water

In the United States, modern tonic water can contain no more than 83 mg of quinine per quarter of a gallon. For it to be considered an anti-malarial medicine, it would take drinking several gallons of tonic water a day to treat the disease. In 2010, the Food and Drug Administration banned over-the-counter quinine because of its severe side effects. Even so, people sometimes rely on tonic water as a home remedy for different ailments, such as leg cramps. The small amount of quinine that modern tonic water contains makes it safe for this application. Tonic water is used successfully to treat muscle cramps that are associated with gastroenteritis.

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About the Author

Cristina Garcia has been a freelance writer since 2009 when she published her first travel ebook. She is a zoologist and has several years of wildlife research experience studying wild canid ecology and behavior. She holds a master's degree in geographical information science from the University of Edinburgh in the U.K., specializing in satellite remote sensing techniques for ecology.