fizziness is the bubbling that occurs in a sparkling wine when the bottle is opened and the wine is poured into a glass. In a sealed bottle the cork maintains a pressure of up to 6 atmospheres and there is equilibrium between the dissolved carbon dioxide and the carbon dioxide in the head space. When the bottle is opened and the wine is poured into a glass, the pressure above the wine is reduced to ambient pressure of about 1 atmosphere and the wine is said to be supersaturated with carbon dioxide.
