Champagne Bubbles Stay Stable Due to One Key Chemical Ingredient

Scientists from Brown University and the University of Toulouse have popped the cork on the mystery behind champagne bubbles’ ordered fizzing. Their study, published in Physical Review Fluids, offers a new understanding of the stable bubble chains observed in champagne, sparking fresh insights into the field of fluid mechanics.

The research team, led by Brown engineering Professor Roberto Zenit, set out to investigate the stability of bubble chains in carbonated beverages like champagne, beer and sparkling water. Their findings revealed that soap-like chemicals called surfactants and bubble size are crucial factors in stabilizing bubble chains.

Champagne bubbles’ unique properties

Champagne bubbles are known for their unique behavior, rising rapidly in a single-file line, and persisting for an extended period. This contrasts with other carbonated drinks like beer, which displays unstable bubble chains with multiple bubbles veering off to the side.

Zenit and his team ran a number of experiments that could probably be performed in your local bar, pouring a series of carbonated drinks, including Tecate beer, a Spanish brut and Charles de Cazanove champagne.

Rather than steins or flute glasses, these drinks were poured into rectangular plexiglass chambers, which could have gas pumped in externally. The team then tested two factors that they suspected would alter bubble chain stability: the number of surfactants present and the bubble size.

Zenit and his team noted that the protein molecules that give Champagne its distinct flavor also act as surfactants. These minimize the tensions between the gas bubbles and the surrounding liquid, making for a smooth rise to the top. Without surfactants, in liquids such as carbonated water, the wake flows left by bubbles can disrupt the progress of following bubbles, creating haphazard chains. “This wake, this velocity disturbance, causes the bubbles to be knocked out,” Zenit said. “Instead of having one line, the bubbles end up going up in more of a cone.” Adding surfactants to normally unstable liquids created ordered bubble flows, making beer as stable as champagne.

Larger bubbles demonstrated a wake similar to that of surfactant-assisted bubbles, resulting in a smooth rise and stable chains. However, the bubbles in beverages are typically small, making surfactants the primary ingredient for producing straight and stable chains.

Understanding aeration tanks and ocean seeps

Some of the team’s questions couldn’t be solved using physical experimentation. A set of computational experiments provided answers to how much surfactant can enter the gas bubbles, as well as the bubbles’ weight and speed.

The implications of these findings extend far beyond understanding the science of celebratory toasts. The research offers a general framework for understanding cluster formation in bubbly flows, which are used widely across different economically and societally important industries. Improved comprehension of bubble clustering could benefit technologies utilizing bubble-induced mixing, such as aeration tanks at water treatment facilities. It could also help explain ocean seeps, where methane and carbon dioxide emerge from the ocean floor.

Moving forward, the researchers plan to continue exploring the physics of stable bubble chains. “We’re interested in how these bubbles move and their relationship to industrial applications and in nature,” Zenit said.

Reference: Atasi O, Ravisankar M, Legendre D and Zenit R. The presence of surfactants controls the stability of bubble chains in carbonated drinks. Phys. Rev. Fluid. 2023. 

This article is a rework of a press release issued by Brown University. Material has been edited for length and content.