The Physics of Champagne’s Fascinating Effervescence

The popping of the cork, the fizz of the pour and the clink of champagne glasses toasting are the ingredients for a celebration in many parts of the world. Champagne itself dates back to ancient Rome, but the biggest breakthroughs in the modern form of the drink came from a trio of savvy women from the Champagne region of northeastern France in the 19th century.

Now, scientists are adding another chapter to the bubbly story of champagne by discovering why the little effervescent bubbles of joy bubble up in a straight line.

[Related: Popping a champagne cork creates supersonic shockwaves.]

In a study published May 3 in the journal physical revision fluids, a team discovered that stable bubble chains in champagne and other sparkling wines occur due to ingredients that act similarly to soap-like compounds called surfactants. Surfactant-like molecules help reduce stresses between the liquid and gas bubbles, creating a smooth rise to the surface.

The champagne bubbles form neat single row lines. CREDIT: Madeline Federle and Colin Sullivan.

In this new study, a team performed numerical and physical experiments on four carbonated drinks to investigate the stability of bubble chains. Depending on the drink, the fluid mechanics are quite different. For example, champagne and sparkling wine have bubbles of gas that appear to rapidly climb to the top of the glass in single file like little ants, and continue to do so for some time. In beer and soft drinks, the bubbles drift to one side and the chains of bubbles are not as stable.

To observe the chains of bubbles, the team poured glasses of carbonated beverages that included Pellegrino sparkling water, Tecate beer, Charles de Cazanove champagne and a Spanish-style sparkling wine called brut.

They then filled small rectangular Plexiglas containers with liquid and pumped in gas to create different types of bubble chains. They gradually added surfactants or increased the size of the bubble. They found that the larger bubbles could be stabilized even without the surfactants. When they maintained a fixed bubble size with only added surfactants, the chains could go from unstable to stable.

Beer bubbles are not as close together as champagne bubbles. CREDIT: Madeline Federle and Colin Sullivan.

The authors found that the stability of the bubbles is actually affected by the size of the bubbles themselves. Chains with large bubbles have a wake similar to bubbles with contaminants, leading to a smooth climb and stable chains.

“The theory is that in champagne these contaminants that act as surfactants are the good stuff,” co-author and Brown University engineer Roberto Zenit said in a statement. “These protein molecules that give flavor and uniqueness to the liquid are what make the bubble chains they produce stable.”

Since the bubbles are always quite small in drinks, surfactants are the key ingredient in producing the straight, stable chains we see in champagne. Although beer also contains surfactant-like molecules, the bubbles may or may not ascend in linear chains, depending on the type of beer. Bubbles in carbonated water like mineral water are always unstable because there are no contaminants to help the bubbles move smoothly through the wake of the flows.

[Related: This pretty blue fog only happens in warm champagne.]

“This wake, this alteration in speed, causes the bubbles to be removed,” Zenit said. “Instead of having a line, the bubbles end up going up in more of a cone.”

The findings could add to a better understanding of how fluid mechanics works, particularly clump formation in bubbling flow, which has economic and social value. The global carbonated beverage market was valued at a whopping $221.6 billion in 2020.

Technologies that use bubble-induced mixing, such as aeration tanks in water treatment facilities and in winemaking, could greatly benefit from a better understanding of how bubbles clump together, their origins, and how to predict their appearance. . Understanding these fluxes may also help better explain ocean seeps, when methane and carbon dioxide rise from the ocean floor.

“This is the type of investigation that I have been working on for years,” Zenit said. “Most people have never seen an ocean seep or aeration tank, but most have had a soda, a beer or a glass of champagne. When talking about champagne and beer, our master plan is to make people understand that fluid mechanics is important in their daily lives.”

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