Effervescence is the escape of gas from an aqueous solution and the foaming or fizzing that results from a release of the gas. The word effervescence is derived from the Latin verb fervere preceded by the adverb ex, which means to boil. It has the same linguistic root as the word fermentation, a complex biochemical reaction leading amongst others to the production of carbon dioxide and to the subsequent liberation of CO₂ gas from the solution when this latter becomes supersaturated with respect to this gas. The making of beer, wine, or champagne, by fermentation is thus also accompanied by effervescence of CO₂ from the barrel where the process occurs.

Les boissons gazeuses sont des boissons qui contiennent du dioxyde de carbone dissous provenant directement d’une source minérale, obtenu par fermentation ou ajouté artificiellement.