Unveiling CO2 heterogeneous freezing plumes during champagne cork popping

Abstract

Cork popping from clear transparent bottles of champagne stored at different temperatures (namely, 6, 12, and 20 °C) was filmed through high-speed video imaging in the visible light spectrum. During the cork popping process, a plume mainly composed of gaseous CO2 with traces of water vapour freely expands out of the bottleneck through ambient air. Most interestingly, for the bottles stored at 20 °C, the characteristic grey-white cloud of fog classically observed above the bottlenecks of champagne stored at lower temperatures simply disappeared. It is replaced by a more evanescent plume, surprisingly blue, starting from the bottleneck. We suggest that heterogeneous freezing of CO2 occurs on ice water clusters homogeneously nucleated in the bottlenecks, depending on the saturation ratio experienced by gas-phase CO2 after adiabatic expansion (indeed highly bottle temperature dependent). Moreover, and as observed for the bottles stored at 20 °C, we show that the freezing of only a small portion of all the available CO2 is able to pump the energy released through adiabatic expansion, thus completely inhibiting the condensation of water vapour found in air packages adjacent to the gas volume gushing out of the bottleneck.

Under-expanded supersonic CO 2 freezing jets during champagne cork popping

“…As already unveiled in a previous study, for the bottle stored at 20°C, a blue plume appears about 250 μs after the cork popping process and develops above the bottleneck for several milliseconds until it progressively vanishes. It was emphasized that blue haze is the signature of a partial and transient heterogeneous freezing of gas-phase CO 2 on ice water clusters homogeneously nucleated in the bottlenecks ( 11 ). Blue haze is indeed typical of the Rayleigh scattering of light by clusters much smaller than the wavelengths of ambient light ranging from 0.4 to 0.8 μm.…”

“…Nevertheless, with homogeneous nucleation rates close to zero for dry ice CO 2 clusters, the freezing of gas-phase CO 2 through homogeneous nucleation remains thermodynamically impossible for the bottles stored at 20° and 30°C (despite saturation ratios substantially higher than 1 for gas-phase CO 2 after adiabatic expansion). In a previous article, the following scenario was proposed to account for the formation of a blue haze as observed above the bottlenecks of a 20°C cork popping bottle ( 11 ). After adiabatic expansion of the CO 2 /H 2 O gas mixture, clusters of ice water appear in the bottlenecks through homogeneous nucleation (given their very high rate of homogeneous nucleation).…”

“…Note that into every bottle of this batch, the volume V G of gas phase in the headspace under the cork is close to 25 ml, whereas the volume V L of champagne (i.e., the liquid phase) is 75 cl. Recently, the following relationship was theoretically determined for the newly recovered equilibrium pressure of gas-phase CO 2 in the corked bottles after the disgorging step was achieved (denoted as PCBCO2 and expressed in Pa) ( 11 )PCBCO2≈nTkHfalse(italicRTfalse)2VL(VnormalG+knormalHitalicRTVnormalL)2with n T being the total number of CO 2 moles produced in a sealed bottle after the prise de mousse (i.e., 0.2 mol in the present case).…”

“…Recently, cork popping from clear transparent bottles of champagne stored at different temperatures (namely, 6°, 12°, and 20°C) was filmed through high-speed video imaging ( 11 ). On the basis of this set of experiments, the situation has appeared really more complex and subtle than described before.…”

Hétéro-nucléation de cristaux de neige carbonique au débouchage d’une bouteille de champagne

“…La constante de Henry du CO 2 y est d'environ 1,5 g/l/bar à 20 °C, alors qu'elle n'est que de l'ordre de 20 mg/l/bar pour l'oxygène, par exemple. Or, la dépendance exponentielle en température de la constante de Henry d'un gaz en solution aqueuse induit une très forte sensibilité de sa solubilité avec la température (plus la Par application de la loi de Henry et de celle des gaz parfaits, on peut calculer la pression de gaz carbonique qui règne dans une bouteille en fonction de sa température T. En tenant compte de l'étape qui consiste à retirer le dépôt de levures mortes de la bouteille sous l'effet de la pression après la prise de mousse, puis à reboucher immédiatement ladite bouteille avec un bouchon en liège, la pression de gaz carbonique qui règne dans une bouteille de champagne prête à être dégustée s'exprime comme suit [4] : 2 (2), où n T est le nombre de moles de CO 2 piégées dans la bouteille en fin de fermentation, V L est le volume de champagne, V G est le volume du ciel gazeux dans le col de bouteille et R est la constante des gaz parfaits.…”