We study a few physical phenomena that are relevant mostly to carbonated beverages, and partly to problems of CO2 sequestration [1]. Our experiments and analysis include the chemically most simple case of a water-CO2 solution (a “pure soda”), but equally apply to real sparkling beverages such as Champagne, beers and colas. Our goal is to understand the kinetics of CO2 exchange through the liquid-gas phase interface, in response to e.g. a transient change in pressure or to mechanical perturbation. We thus address frequently asked and apparently simple questions about how fast the liquid inside can ingest or reject carbon dioxide, how opening of a Champagne bottle modifies the gas content inside, and what is the consequence of shaking the bottle on the pressure and the later occurrence of effervescence and gushing. We report observations from a set of dedicated experiments, whereby CO2 pressure, concentration, and convection flows are visualized. The experiments reveal the onset and destabilization of diffusion fronts, and the effect of bubbling induced by shaking on internal pressure. Results are rationalized through considerations involving molecular diffusion, Rayleigh-Taylor instability [1] and the Epstein-Plesset [2] mechanism of soluble gas bubble kinetics.
[1] J. A. Neufeld et al., Geophys. Res. Lett. 37, L22404 (2010); A. Riaz et al., J. Fluid Mech. 548, 87 (2006); S. Backhaus et al., Phys. Rev. Lett. 106, 104501(2011)
[2] P.S. Epstein and M.S. Plesset, J. Chem. Phys. 18, 1505 (1950)
vreme@crpp-bordeaux.cnrs.fr
