Free Republic

Protein splits carbon dioxide to give fizz its flavor 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...