They have discovered that ethanol is the main molecule (along with water) responsible for the value of CO2 diffusion coefficients in champagne, and is therefore an essential molecule to better understand the CO2 bubble formation and growth in these beverages.
The results from the University of Reims Champagne-Ardenne in France could have applications for evaluating the diffusion of CO2 molecules in water/alcohol mixtures that are commonly used in physical chemistry.
Previous research has shown that two phenomena are responsible for the emission of CO2 bubbles in sparkling beverages such as Champagne wines, Phys.Org reported.
The first phenomenon arises because these beverages are supersaturated with CO2, and CO2 emission occurs at the interface between a supersaturated aqueous solution and a gas phase (the air above the glass).
The second phenomenon responsible for CO2 bubble emission is effervescence, which refers to the formation of bubbles from tiny gas pockets trapped within immersed particles, such as cellulose fibres, crystals, or even within scratches or etchings on the glass surface.
When the radius of the gas pocket trapped within the particle or scratch exceeds a critical size (about 0.2 micrometres at the opening of a Champagne bottle), dissolved CO2 can diffuse into the gas pocket and make the bubble grow.
As the CO2 diffuses, many CO2 bubbles are released in the Champagne in the form of bubble trains.
The study was published in The Journal of Physical Chemistry Letters.
PTI