Questions and answers on champagne’s bubbliness...

By Gérard Liger-Belair, Reims University.

How can you explain the size of the bubbles?

Champagne bubbles, nourished by dissolved carbon dioxide, grow as they rise to the surface.
To start with, they are microscopic, and may reach 1 millimeter in diameter after rising about ten centimetres, at the beginning of the tasting session. By the end of the tasting session, the champagne, whose carbon dioxide has been depleted, releases only considerably smaller bubbles. Of course, other parameters also influence bubble size: temperature at which served, and pressure. However, the main parameter remains the content of dissolved carbon dioxide.

Why are the bubbles bigger in plastic glasses?

That is due to the polyethylene, the material that plastic glasses are made of. This is a very hydrophobic material; water is scarcely able to dampen it.
The bubbles cling to the walls of the cups, since the plastic prefers contact with the gas to contact with liquid. The bubbles will get bigger on the wall along which they will slide up to the surface.
This difference in tolerance to water between glass and plastic explains why the bubbles are fine in a glass or crystal champagne flute and large in a plastic cup.
Another difference will be the absence of a trail of bubbles in a plastic cup: in order to form a fine string, the bubbles must follow each other very quickly without getting caught on the wall of the container.

Is it recommended to wash champagne flutes in a dishwasher?

It is advised against, because of the products used, which leave a fine film of detergent on the surface of the glass. This leads to the bubbles bursting on the surface.
Ideally, rinse flutes in very hot water and dry them with a soft cloth.

What causes the bubbling over the glasses?

Hundreds of bubbles burst each second on the surface of the champagne. Each bubble produces a fine jet of liquid. The surface of the champagne is thus dotted with hundreds of miniscule jets which cause the bubbling. There is an estimated average of five droplets per exploding bubble. The spray over the flute is made up of very fine droplets, a couple of hundred microns in diameter.

What is the difference between beer and champagne bubbles?

Essentially there are two: The volume of dissolved carbon dioxide in beer is two times lower than that in champagne. The result is that the bubbles grow more slowly and so are smaller than champagne bubbles. Beer is richer in tensioactive macromolecules, which make the bubbles rigid and extend their life span. That is why beer bubbles form a thick froth, unlike the ephemeral bubbles in champagne.

What is the significance of the temperature at which it is served?

The higher the temperature, the faster the liquid carbon dioxide changes to bubbles. So there is even greater effervescence and the bubbles are even larger. A champagne served at 15° will produce bubbles at a rate more than 50% higher than that of champagne served at 5°.

What is the effect of lipstick?

Lipstick has no effect on the intensity of effervescence but does cause the bubbles to burst. What happens is that on the surface the bubbles are separated from the air by a thin liquid film. The lipstick’s fat content expands over this film, making it thinner so that it ends up breaking.

Which is the better choice: a champagne saucer or a flute?

The saucer does not allow appreciation of all of a champagne’s qualities and conceals the movement of the bubbles towards the surface. However, it encourages a better dispersal of the gas, diluting the aromas. The success of champagne flutes is ever increasing. They make it possible to appreciate the movement of the bubbles properly, concentrating the aromas, which they release when the bubbles burst, so that the champagne’s effervescence is extended.

La Vigne - December 2006