Gérard Ligier-Belair, the bubble magician

Sep 17, 2020 • 4 mins

Gérard Liger-Belair is a scientist who reads champagne bubbles... Physics Professor at Reims Champagne-Ardenne University, in 2012 he created the Effervescence laboratory, studying all effervescent drinks. A world first at the cutting edge of imaging technologies, which immerse us into the world of the infinitely small, in the interstices of gas and air.

A way of comprehending what hides on the other side of the glass, understanding the mechanisms and expressing their beauty. Because the spectacular images he collects are an invitation on a journey, or a diving into the heart of a strange and fascinating world. An interview with the bubble magician, member of the champagne faithful.

The whirlwinds generated by the effervescence on the surface of a champagne flute are spectacular and reminiscent of ocean movement - it’s very poetic!

GLB : Yes, there are imaging techniques which show these movements of champagne which are invisible to the naked eye. These little whirlwinds accelerate the evaporation of champagne’s aromas when tasted and are identical to those moving on the ocean surface, on a far bigger scale. As science progresses, Nature reveals to us increasingly subtle mechanisms that we can often find on incredibly different scales. To paraphrase philosopher Michel Onfray with whom I recently worked on a book: “The microcosm of the champagne flute expresses the macrocosm of the ocean’s surface. The infinitely small world of the glass teaches about the infinite vastness surrounding us.“

The crucial stage of opening the bottle is another facet to your research. Tell us about it.

GLB : We studied this uncorking phase using scientific imaging and super high-speed cameras; we observed the cloud of condensation which forms above the neck. This is caused by the shock decompression of the volume of gas which springs out and a sudden fall in the temperature of the bottle neck. This cloud is blue because the size of the condensation droplets is smaller than the length of the visible light rays. An analogical phenomenon which makes the sky appear blue to us!

However, there is a problematic and uncontrollable phenomenon: the gushing.

GLB : We estimate that between one and five million bottles are affected by this phenomenon every year, which is not insignificant. We do not yet know all the causes of this phenomenon, but the uncontrolled production of bubbles at opening is potentially dramatic when it occurs; you can lose up to half the volume of the bottle in less than a second. Everything happens in the first thousandths of a second after the bottle is opened. This is why we use cameras that can film up to 60,000 images a second to observe and understand it !

Which laws of physics dictate the fineness of the bubble?

GLB : There are indeed several, but the main cause is the moderate quantity of carbon dioxide dissolved in the bottle. The more a champagne ages, the more the concentration of dissolved carbon dioxide falls which explains why older champagnes generally produce fine bubbles

Are champagne bubbles the finest of all bubbles?

GLB : Not at all! Beer bubbles are nearly twice as fine! As are those of crémants and those of demi-mousse champagnes (made with a reduced quantity of sugar).

How important is the serving temperature of a champagne?

GLB : It is essential because the pressure increases with the temperature and the force exerted by carbon dioxide under pressure in the bottle neck is how the cork is ejected. The cooler the bottle, the more CO2 will be dissolved and the more the pressure in the bottle neck will be contained. Hence the importance of chilling your champagne before serving! There is no point in having glasses that are too clean because the minuscule dust elements on the glass allow the bubbles to form.

Which glass should you use for champagne?

GLB : Champagne served in a coupe does not retain its sparkle and often seems to have less of a bouquet. The narrow opening of a flute effectively prolongs the sparkle but a flute that is too narrow runs the risk of excessively concentrating the carbon dioxide which will result in an unpleasant stinging in the nose. The right compromise is therefore mid-way between the two, a shape close to that of a glass for serving still wine.