The bubbles in champagne not only supply a loud ceremonial pop when a bottle is uncorked but also enhance the wine’s flavour, according to French scientists.

They showed that the bubbles carry aromas up to the surface and leave them hovering above the sparkling liquid in a fine mist.

As a result, when you lower your head to take a sip, your nose is met by a bouquet of buttery and fruity fragrances that defines the drink.

“People have been making and enjoying champagne for hundreds of years but it’s only now that we’re beginning to understand the science behind what makes these wines so good,” said Tony Milanowski, a winemaker and director of the BA course in viticulture at Plumpton College in Sussex.

The fizz in champagne has this effect because the molecules responsible for its aroma come attached to fatty acids released by the yeast added to the wine during the fermentation process, or directly from the grapes. The acids are double-ended compounds with one end that is attracted to water and another that shuns it.

As a result the molecules cluster around the surface of the bubbles, with one end in the bubble and the other in the liquid. As the bubbles rise to the surface, the aromatic molecules are carried upwards and released as aerosols as the bubble pops at the surface.

The huge amount of gas compressed in a bottle of champagne means that a constant stream of the aroma molecules are thrown upwards into the air. Around 5l of carbon dioxide has to escape from a typical 0.75l bottle of champagne.

Using a technique called mass spectroscopy, which identifies molecules based on how heavy they are, the scientists identified which compounds were present in the air just above the champagne’s surface. The study, published today in the journal PNAS (Proceedings of the National Academy of Sciences), found high levels of the chemicals responsible for aroma and flavour.

These included a chemical called Annuionone G, which contributes to the fruity aroma of wines such as syrah and chardonnay and another compound called gamma-decalactone, which gives a peachy aroma.

In a second part of the study, yet to be published, the researchers investigated other sparkling wines, including cava and prosecco, and found a similar effect.

The same mechanism is also likely to be at work in ordinary fizzy drinks, but because these tend to contain less aromatic molecules the effect on smell and flavour is not as pronounced. “Wines have a lot more aroma than the classic soda,” said Gérard Liger-Belair, a chemist at the University of Reims Champagne-Ardenne, who led the research.

The findings may explain why a narrow flute is the preferred glass to drink champagne from. “Intuitively it makes sense because it would concentrate the aromas in a small area,” said Professor Liger-Belair.

For champagne and traditional sparkling wines the grapes are normally handpicked and hand-pressed to give a high-quality juice without much colour or tannin. After being fermented the juice from several types of grape — typically Pinot Noir and chardonnay is blended together.

Sugar and yeast is added to this base wine and it is bottled. This means all the carbon dioxide released in the second fermentation is captured. The bottle is matured during which time the bubbles become smaller and the flavours develop.

The ability of sparkling wines to throw out their aromas means that they can be served at colder temperatures, without losing their flavour. “They definitely have an advantage over non-sparkling wines in this respect,” said Mr Milanowski.

However, there may be additional reasons why sparkling wines are widely appreciated. “There’s also the aesthetic quality — a nice fine mousse on the surface is going to enhance the experience, whether the flavour is better or not. And with sparkling wines you get a little tickle on the nose, which puts you in a happy mood,” he said.

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