Open a can of soda pop or beer, and the little “pshtt” sound indicates that carbonic acid has just started to separate into water and carbon dioxide. When it’s opened to the atmosphere, carbonic acid releases CO2 in the form of little bubbles.
Cold temperature keeps it suspended longer. That’s why warm cola tastes awful once the CO2 bubbles have escaped. In theater class, we used to make stage “whiskey” by boiling Coca-Cola, diluted with water. This nasty stale drink looks like actual whiskey. The face of the actor drinking it had audiences convinced it was the real stuff.
In nature, carbonic acid is slowly dissolving the northwest Georgia mountains. Rainwater picks it up from plant roots and carries it through the limestone bedrock of Walker and Dade County, carving out hollows and caves in the process.
Many soft drinks contain small amounts of phosphoric acid. It adds a tart flavor and is harmless in low concentration. The old urban legend claiming that soda pop dissolves flesh and is harmful to consume probably relates to this acid. But the human stomach is well protected against acidity, otherwise it would digest itself.
Weak phosphoric acid is also good for cleaning metal. That’s why some car detailers use Cola for scrubbing raw metal parts.
Household vinegar gets its sour character from yet another type. Full-strength acetic acid has a pungent, nostril-clearing smell. Photo labs had that aroma because acetic acid served as a “stop bath” during film and print development, interrupting the action of the developer solution.
In its weak form, vinegar makes a good organic cleaning aid. Because calcium (lime) dissolves in acid, vinegar can be used to clean water stains off bathroom fixtures and coffee pots.
When there’s a strong brown deposit in a shower tub or sink, using so much vinegar can be annoying. The better choice in that case is citric acid, the stuff that flavors oranges, lemons and grapefruit. It can be purchased as a food-grade powder. Instead of using it for baking, one can make a paste with a bit of water, and let it sit overnight on the lime stains.
They can later be scrubbed away completely, without any odor.
Rudi Kiefer, Ph.D., is a professor at Brenau University, teaching physical and health sciences on Brenau’s Georgia campuses and in China. His column appears Sundays and at gainesvilletimes.com.