What does the size of the bubbles say about the quality of your sparkling wine?
There are around 1 million bubbles in a glass of cava and sparkling wines have long been judged by the size of their bubbles. Fine bubbles, coarse bubbles, persistent bubbles - from the finest sparklers, some say, come a million pinpricks of air, producing more foam or mousse than a gurgling aquarium... Or maybe it's all nonsense.
According to chemistry professor Gérard Liger-Belair at the University of Reims, who specializes in bubbles in sparkling drinks, the size of the bubbles primarily says something about the age of the wine - not its quality.
He explains that the growth rate of bubbles rising in a wine glass is related to the amount of dissolved carbon dioxide present in the wine. The more carbon dioxide dissolved in a wine, the higher the growth rate, and therefore the larger the bubbles. The less dissolved CO2, the smaller the bubbles.
According to the professor, young sparkling wines contain around 11 grams of CO2 per liter of dissolved carbon dioxide. During the aging process, which can last several years, carbon dioxide escapes from the sealed bottles, either through the cork or through the lid used to seal the bottle. In other words, the amount of dissolved CO2 gradually decreases over time.
This means that if you uncork an old cava or sparkling wine, the bubbles will be smaller, simply because there is less dissolved carbon dioxide in the wine, regardless of the wine's inherent quality. "If you buy a bottle of poor-quality sparkling wine and forget about it in your cellar for 10 years, the bubbles will be nice and elegant in your glass, but the wine will still be undrinkable," he says.
