Why Does Soda Have CO2?

Whatever your favorite flavor, bubbles are the defining essence of soda pop. The effervescence of soda arises from dissolved carbon dioxide, or CO2, which forms bubbles as it transitions from a liquid to a gaseous state. The origins of soda pop date back to the late 18th and early 19th centuries, when pharmacists mixed carbonated water with various ingredients to produce medicinal tonics. Over time, customers increasingly purchased soda for its pleasing flavor and its original role as a healing concoction faded into obscurity.

Making Bubbles

Humans have revered mineral springs as sources of healing waters since ancient times. Thousands continue to flock to mineral springs around the world each year to drink from or bathe in these waters. In an effort to recreate the healing waters of naturally effervescent mineral springs, Englishman Joseph Priestly devised a technique in 1772 to incorporate carbon dioxide into water. His process to generate carbonated water became the foundation of what would eventually develop into the modern soda industry.

Carbonated Medicinal Tonics

As carbonated water, also known as soda water, became increasingly commonplace in urban areas, pharmacists in Europe and the United States began mixing the liquid with herbal powders and syrups to create medicinal tonics. Common ingredients in early carbonated tonics included ginger, peppermint, quinine, cream of tartar, kola nuts, sassafras root, potash and lemon juice. Pharmacists commonly added sugar to their concoctions to make them more palatable. Popularized by Swiss jeweler and entrepreneur Jacob Schweppe, ginger-flavored soda water was a favorite tonic in the late 18th century. Druggists and doctors prescribed carbonated tonics for a variety of ailments, including digestive disorders, infections, scurvy and cancer.

From Tonic to Treat

As technological advances made carbonated tonics more accessible to the masses, marketers of these products made a surprising discovery --- many people drank the potions because they liked the taste rather than for medicinal purposes. Words like "refreshing" and "delicious" crept into local druggists' soda fountain advertising. Nineteenth-century pharmacists, including Charles Alderton, John Pemberton and Caleb Bradham, are credited with creating the syrups that gave rise to some of the world's most popular sodas.

The Pop Bottle Revolution

The invention of the soda fountain in the early 19th century increased the accessibility and popularity of carbonated sodas. Having to visit your local pharmacy to get a soda, however, limited the market for these products. A series of technological advances in the late 1800s led to the invention of bottling systems that reliably preserved the key characteristic driving the popularity of soda --- the carbonation. The "pop" bottle revolutionized the burgeoning soda industry by increasing product availability to a substantially broader market than had been previously possible. Astounding industry growth continued throughout the 20th century. As of 2005, the USDA reports that the average American consumes nearly 51 gallons of soda pop yearly.