Using sound to assess the size, and quality, of bubbles in sparkling wines

Sorry sommeliers, but the best way to assess a sparkling wine’s quality may involve anyone’s sense of taste or smell. When judging a specific lot of wine, the most objective measurement turns out to be the sound of the wine, or more specifically, the sound of the bubbles inside. The most desirable bubbles are tiny, which not only tickle the tongue but also resonate at a different frequencies of sound than larger bubbles, not unlike a smaller bell versus a large one. So rather than rely on people’s mouths to test a vintage’s quality, vineyards may start employing hydrophones to make sure every batch of champagne and sparkling wine is up to snuff.

You’d be forgiven if you’ve never put a glass to your own ear to listen to a glass of sparkling wine before taking a sip. Detecting the exact nuances of each batch of bubbles was surprisingly tricky for researchers as well, even with years of experience recording other sounds underwater. Early tests using standard hydrophones, or underwater microphones, were impeded by the bubbles themselves. As the carbonation would rise through a glass, the bubbles would stick and cover the outer surface of the hydrophone, significantly altering the data it could collect. A smaller, more specialized hydrophone had to be used to compensate for the bubble build-up, meaning your ear really doesn’t stand a chance at picking up the level of detail necessary to asses sparkling wine or champagne.

Tips for tinier bubbles

With some iteration, researchers were able to identify the sounds of optimally tiny bubbles, which should help vineyards more accurately judge the quality of their product. While improved quality control should be good for vineyards, this research also revealed information that can be put to use by those of us who don’t have a piezoelectric transducer-based hydrophone at home. While trying to get consistent measurements of the bubble’s resonance, researchers found that the shape and material of the wine’s container greatly influenced the size of the bubbles produced. Champagne flutes help the carbonation produce smaller, consistent bubbles, just as you’d hope. On the other end of the spectrum, a flat-bottomed Styrofoam cup did just the opposite, making for bulkier bubbles, robbing the wine of its potential.

Once you have some delightfully tiny effervescence in a proper champagne flute, the best way to prolong the carbonation is by keeping your bottle and glass consistently cold. A separate investigation into preserving carbonation in open bottles of sparkling wine looked at stoppers, spoon handles and more, and found the best way to keep the bubbles coming was to never let a bottle warm up after it had been opened. So if you have the equipment to really check your next glass of bubbly, make sure your glass, and hydrophone, are properly chilled.

Source: Pop the bubbly and hear the quality by Acoustical Society of America, EurekAlert!