While guzzling down your third champagne at your friend’s wedding, you may have not noticed that the bubbles in champagne are markedly different than the ones in other carbonated drinks (including some beers, sodas, and sparkling water).

In a flute of champagne, the bubbles stream upwards in organised, single-file chains. This is unlike other carbonated beverages, where the wake of rising bubbles knocks other bubbles sideways so that multiple bubbles rise simultaneously.

A group of US and French fluid mechanists have figured out why champagne forms these stable ‘bubble chains’ when other bubbly drinks do not. The experiments revealed that the stable bubble chains in champagne and other sparkling wines are due to the presence of ingredients that act as soap-like compounds called surfactants.

Champagne, prosecco and other sparkling wines contain more surfactants than other carbonated drinks

But when a liquid contains enough surfactants, the structure of a bubble’s wake changes so that the trailing bubble is sucked up in line with the one before it, resulting in a (stable) vertical column. Champagne, prosecco and other sparkling wines contain more surfactants than other carbonated drinks.

The stability of bubbles in carbonated beverages is influenced by the size of the bubbles themselves and the presence of surfactant-like molecules. Experiments show that the chains with large bubbles have a wake similar to that of bubbles with surfactants, leading to a smooth rise and stable chains.

In beverages, however, bubbles are always small. It makes surfactants the key ingredient to producing straight and stable chains. Beer, for example, also contains some surfactant-like molecules but, depending on the type of beer, the bubbles can rise in straight chains or not. In contrast, bubbles in carbonated water are always unstable since there are no surfactants helping the bubbles move smoothly through the wake flows left behind by the other bubbles in the chain.