The light, sparkly fizz of champagne owes its taste to the tongue’s sense of sour. New studies in mice reveal how the tongue tastes carbonation, solving an old puzzle of why some mountain climbers get the “champagne blues.”
Tasting fizz begins with a special protein that’s tethered to sour-sensing taste cells on the tongue, researchers report in the Oct. 16 Science. This protein, the enzyme carbonic anhydrase 4, splits carbon dioxide into bicarbonate ions and free protons, which stimulate the sour-sensing cells.
Scientists have long thought that the taste of carbonated beverages emerged from the physical bursting of bubbles on the tongue, says study author Charles Zuker, a neuroscientist now at Columbia University who did the work while at the University of California, San Diego. But bubbly drinks still taste distinctly carbonated when they are imbibed in a pressure chamber where bubbles don’t burst.