Flow Visualization in engraved champagne tasting glasses

Glass shape and especially his open aperture is suspected to play an important role as concerns the kinetics of CO2 and flavor release during champagne tasting. In recent years, much interest has been devoted to depict each and every parameter involved in the release of gaseous CO2 from glasses poured with champagne. One cannot understand the bubbling and aromatic exhalation events in champagne tasting, however, without studying the flow-mixing mechanisms inside the glass. Indeed, a key assumption is that a link of causality may exist between flow structures created in the wine due to bubble motion and the process of flavor exhalation. In this article, a collection of various ascending bubble driven flow patterns and mixing phenomena, which illustrate the fine interplay between ascending bubbles and the fluid around, were evidenced, through tomography techniques. Moreover, the Particle Image Velocimetry (PIV) technique was used in order to reach the velocity field of the ascending bubbles-driven flow patterns found in a flute poured with champagne. The results show that the continuous flow of ascending bubbles strongly modifies the mixing and convection conditions of the liquid medium. Moreover, spontaneous and self-organized convective cells were evidenced at the air/champagne interface through laser tomography. The number, size and velocity of the multiple and self-organized convective cells vary as time proceeds with the continuously decreasing bubble driven champagne flow. We can establish a close link between the number of hydrodynamic instabilities evidenced at the air/champagne interface and the bubble flow rate.