The bubbles in champagne not only supply a loud ceremonial pop when a bottle is uncorked but also enhance the wine’s flavor. Champagne bubbles carry aromas up to the surface, and create a fine mist of the wine’s bouquet. As a result, when you lower your head to take a sip, an explosion of buttery and fruity fragrances that defines the drink meets your nose.
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. This also explains why a narrow flute is the preferred glass to drink champagne from. Champagne flutes concentrate the aromas in a small area.
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 found high levels of the chemicals responsible for aroma and flavor.
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 other carbonated beverages, but because these tend to contain less aromatic molecules, the effect on smell and flavor is not as pronounced.
For champagne and traditional sparkling wines the grapes are normally hand picked and hand pressed to give a high quality juice without much color or tannin. After being fermented, the juices from several types of grape (typically Pinot Noir and Chardonnay) are blended together. Sugar and yeast are added to this base wine, and then it’s 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 flavors develop.
The other benefit of bubbles is the ability of sparkling wines to throw out their aromas means that they can be served at colder temperatures without losing their flavor.
