How Understanding Champagne Bubbles May Improve Energy Efficiency
When you open a bottle of champagne, it's almost always a momentous occasion—and we're not just talking about the cause behind the celebration (whatever it is, congrats!). The physical act of uncorking the bottle is exciting and dramatic, and it's all thanks to carbon dioxide.
It's the release of CO2 that leads to the characteristic “pop” of the cork and the bubbles in your glass. The gas escapes in the form of those bubbles—once the champagne hits the flute, the bubbles form and detach, rising toward the liquid’s surface. When they reach the surface, they pop, emitting that fizzy, crackling sound and letting loose an upward spray of tiny droplets. This phenomenon is known as effervescence, and it’s about three times more active in champagne compared to other carbonated drinks like beer. (See? Champagne really is more festive.) By the time the bottle goes flat, nearly 2 million of those tiny bubbles have popped.
Despite their small size, the bubbles in a bottle of champagne can pack quite a punch. They shoot upwards with a velocity of almost 10 feet per second, reaching heights as high as an inch above the drink's surface. In fact, a champagne cork can pop at speeds up to 31 miles per hour.
We prize them today, but back in the day, bubbles were regarded as a sign of bad winemaking. All that began to change after a long period of unusually cool temperatures—often referred to as the Little Ice Age—hit Europe in the late 13th century. As temperatures dropped, lakes and rivers froze all over the continent, and the winemaking monks at the Abbey of Hautvillers in Champagne, France found their product’s fermentation process halted by the cold. When it warmed up, the fermentation continued, resulting in an excess of carbon dioxide and champagne’s signature fizz. Some bottles accumulated so much extra carbon dioxide that they would explode in their store rooms.
In 1668, a monk new to the abbey, Dom Pierre Pérignon, was tasked with thwarting the pesky double fermentation that caused the exploding casks. However, as tastes changed and demand grew for fizzy wine, Pérignon was instead asked to make the wine even bubblier, and that double fermentation soon became standard in the production of champagne and its signature sparkle.
Now, physicists are using those tiny bubbles to study the real-world applications of effervescence. It might surprise you, but the behavior of bubbles is still a bit of a mystery. Physicist Gérard Liger-Belair, author of Uncorked: The Science of Champagne told Smithsonian.com: “[Bubbles] play a crucial role in many natural as well as industrial processes—in chemical and mechanical engineering, oceanography, geophysics, technology, and even medicine. Nevertheless, their behavior is often surprising and, in many cases, still not fully understood.”
The behavior of bubbles found in boiling water in steam turbines closely resembles that of the bubbles in chilled champagne. Both types of bubbles undergo what is called Ostwald ripening (named for German chemist Wilhelm Ostwald, who discovered the phenomenon), wherein small particles give way to the more energetically stable larger particles. Under Ostwald ripening, smaller bubbles collapse in favor of larger bubbles, until only one large bubble remains. The rate at which the bubbles form relies on how fast the liquid changes to gas, and since this change occurs at the surface of the bubble, the faster the liquid molecules reach the bubble’s surface, the faster the rate of bubble formation and growth as the evaporation rate accelerates.
No one can quite settle on an answer as to how quickly different-sized bubbles form in liquids, and it's that missing link that could potentially serve to improve boiler systems and steam-powered reactors. When bubbles pop, they exert a small amount of force that, over time, can cause wear on things like pipes and propeller blades where boiling water is an occupational hazard. While that sort of hardware is designed to stave off such effects, scientists are now trying to better understand the source of the problem rather than just playing defense. The aim is to prevent degradation and optimize the efficiency in steam-powered technologies, and such studies could eventually be useful in other fields, like with foams or metal alloys.
It's with that intention that scientists continue to study bubbles and their modern-day applications—far beyond the champagne flute.