The source of champagne's distinctive crackling sound is a complex physics.
It's rare to write about every cool science-y story that comes our way. Each day from December 25 through January 5, we'll post a science story that fell through the cracks in 2020, highlighting it in a special Twelve days of Christmas series. Researchers have found a way to link champagne's distinctive crackle with the bursting of its tiny bubbles.
There's nothing quite like the sound of a glass of champagne. It's well known that the bursting of bubbles produces a sound, but the exact physical mechanism isn't clear. Physicists from Sorbonne University in Paris, France decided to investigate the link between the bursting bubbles and the crackly fizzy sounds. They described their work in a paper published in January.
The first mention of a sparkling wine in France was in 1535 in the Languedoc region. The name Dom Perignon was given to the brand by a 17th-century monk who had the job of getting rid of the bubbles in the abbey's bottled wine. The monk is said to have realized that the bubbles might not be bad after he drank the wine.
The artificial carbonation process was invented by Joseph Priestley, a British chemist, in the 18th century. The scientist started experimenting with the CO2 used by the brewery and found that a bowl of water placed above a liquor became slightly acidic to the taste. The instructions for artificial carbonation were included in a 1772 treatise.
The science of champagne is studied by the researcher at the University of Reims.
The subfield of fluid dynamics has a fascinating topic of carbonation. An article in the journal Physics Today reported that the same pain-repelling brain cells that are activated when we eat spicy food are also activated when we eat carbonation. When the bubbles in champagne burst, they produce droplets that release aromatic compounds believed to enhance the flavor further.
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The size of the bubbles is important for a good glass of champagne. The larger the bubbles, the greater the release of aerosols into the air above the glass. It's possible to hear the size of the bubbles as they rise to the surface in a glass of champagne.
The authors of this latest paper say that the only study to date specifically looking at the acoustic emissions of champagne is the one from 1992.
The bubbles on the walls of the glass give Champagne its effervescence. The bubbles start to grow as they rise to the liquid surface, bursting and collapsing at the surface once they detach from their nucleation sites. The crackling sound is emitted when the bubbles break.
The crackling sound of champagne is caused by bubbles collapsing at the liquid surface.
The French physicists used a glass tank containing tap water and a tank containing a water/surfactant solution for their experiments, since champagne also contains a small volume of surfactant molecule. They injected air bubbles into the tanks using submerged needles. The bubbles would rise to the surface before bursting. All of this was captured on video with two high-speed cameras, while the acoustic emissions were recorded by a microphone above the liquid surface. The acoustic data was removed from the ambient noise.
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AtAPS physics, as written by Katherine Wright.
Pierre and colleagues found that the sound coincides with the break of the bubble. The pressure of the gas inside the bubble increases as it nears the surface. When the bubble explodes, the pressure is released.
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The bubble does not disappear immediately. The part of the bubble that is still submerged creates acoustic waves. The diameter of the hole in the bubble and the volume of gas in the bubble affect the frequencies of this vibration. As the bubble shrinks, the frequencies change, increasing in pitch until the bubble dies. For small champagne bubbles, the beginning of the burst is audible to humans, while for larger bubbles, the whole burst can be heard.
The team thinks that looking for acoustic signatures could shed light on other phenomena that are difficult to image with conventional techniques. This work adds to previous studies on volcano eruptions, breaking waves and bursting soap bubbles, by understanding the acoustic signature of violent hydrodynamic events.
Physical review fluids, 2021. About DOIs can be found in 10.103/physRevFluids.6.013604.
