The science behind soda’s bite

Published 5:00 am Wednesday, August 28, 2013

What gives carbonated drinks their zesty bite? Bubbles might be your first guess — but you’d be wrong.

In fact, bubbles aren’t needed to experience the burning sensation, but they do enhance it, according to a study published recently in the journal PLOS One. The secret behind soda’s sharp taste is the acid that forms on your tongue.

Carbonated beverages are produced by dissolving carbon dioxide in liquid, typically under high pressure. Popping open a can or bottle of the liquid reduces that pressure, releasing the carbon dioxide in the form of bubbles. Enzymes in the mouth convert the carbon dioxide into carbonic acid, which activates pain mechanisms that cause a mild irritation, or “bite.”

The earliest clues that carbonic acid was responsible for this sensation came from mountaineers’ accounts of the “champagne blues.” After pouring a bottle of champagne at the summit, mountaineers who had taken medication for altitude sickness remarked on the drink’s flat taste — despite its fizziness. It turns out the medication blocked the enzyme that converts carbon dioxide into carbonic acid.