It’s New Year’s Eve and revelers around the world will be bursting the bubbles en masse to usher in 2019. Why do people love champagne and other fizzy drinks so much, when most animals turn their noses up when it’s offered? Roberto Zenit, a physicist at the National Autonomous University of Mexico in Mexico, and Javier Rodriguez-Rodriguez of the Carlos III University of Madrid in Spain, argue in the November issue of Physics today that carbonation triggers the same pain receptors in our deep brains that are activated when we eat spicy foods.
“This effervescent sensation you have when you drink a fizzy drink actually triggers similar taste buds,” Zenit said. “Champagne is just wine; what makes it special is the carbonation. It’s a sad day when you drink flat champagne.”
He and Rodriguez-Rodriguez study the behavior of various fluids (including paint), and carbonation is a particularly fascinating subject within that discipline. When the bubbles in champagne burst, they produce droplets that release aromatic compounds that are believed to further enhance the flavor. (If bubbles in a fizzy drink like beer don’t burst, the result is a nice thick head.) And here’s another interesting fact: The bubbles in champagne “ring” at specific resonant frequencies, depending on their size. So it is possible to “hear” the size distribution of bubbles as they rise to the surface in a glass of champagne.
It’s better with bubbles
Most modern carbonated drinks owe 18ecentury British chemist Joseph Priestley. At the time, char was known as a natural process, in the form of underground springs exposed to high pressures that readily absorbed carbon dioxide, making the water “fizzy”. But Priestley invented an artificial carbonation process when he lived next door to a brewery in Leeds. Ever the scientist, he started experimenting with the CO2 used by the brewery and found that a bowl of water placed over a fermenting liquid became slightly sour in taste, much like natural mineral water. He included his simple instructions for artificial carbonation in a 1772 treatise, Impregnate water with solid air.
Champagne is at least 150 years older than Priestley: the first mention of a sparkling wine dates back to 1535 in the Languedoc region of France. The classic brand Dom Perignon owes its name to a 17ecentury monk who was tasked with removing the bubbles that developed in his abbey’s bottled wine, so that the pressure did not rise so high that they exploded. According to legend, upon drinking such a bubbly wine, the monk realized that perhaps the bubbles weren’t so bad, and declared, “Come quickly, brethren, I’m drinking stars!”
Champagne is usually made from grapes picked early in the season, when there is less sugar in the fruit and more acidity. The grapes are pressed and sealed in containers to ferment just like any other wine. CO2 is produced during fermentation but it is allowed to escape as what you want at this stage is a base wine. Then there is a second fermentation, except this time, the CO2 is trapped in the bottle and dissolves in the wine. Finding the right balance is key. You need about six atmospheres of pressure and 18 grams of sugar, with only 0.3 grams of yeast. Otherwise, the resulting champagne will either be too flat, or too much pressure will cause the bottle to explode.
Gerard Liger-Belair, a physicist at the French National Center for Scientific Research (CNRS) at the University of Reims in northeastern France, has been studying the physics of champagne for years and is the author of Uncorked: the science of champagne. He doesn’t finish his experimental samples – usually by the time he’s done the fizz is completely gone. But he’s garnered countless insights into the underlying physics over the years by subjecting champagne to laser tomography, infrared imaging, high-speed video imaging and mathematical modeling.
For example, the size of the bubbles plays a crucial role in a really good glass of champagne. Larger bubbles enhance the release of aerosols into the air above the glass – bubbles on the order of 1.7 mm at the surface. “This result undermines the popular belief that the smaller the bubbles, the better the champagne,” Liger-Belair told the newspaper. Telegraph in 2016. “Small bubbles were the worst in terms of aroma release.”
Tips for the tipsy
Here are a few more pro tips to keep in mind as you imbibe this evening. Be sure to drink your champagne chilled to about 39°F. This reduces the amount of alcohol that gets entrained in each bubble (too much alcohol can overpower the more delicate flavors of the champagne). It also keeps the cork from being expelled too forcefully when popped. Tilt the glass while pouring to avoid a bubbling overflow.
And it’s true that champagne is best drunk from a flute, rather than the wider “coupe” glass supposedly modeled on the 18’s chest.ecentury French queen Marie Antoinette. Apparently the fluted shape produces more aroma-rich CO2 just under the imbiber’s nose, the better to enhance the taste. However, Liger-Belair recommends using a tulip-shaped wine glass to remove CO. to decrease2natural acidity.
There’s one class of people who absolutely shouldn’t get out of the bubble this New Year’s Eve: astronauts aboard the International Space Station. According to Zenit and Rodriguez-Rodriguez, the bubbles in champagne don’t bubble to the surface at such low gravity; they just stay where they were formed. Admittedly, food scientists managed to adapt Coca-Cola and Pepsi for tests aboard the space shuttle in 1985 Challengerand the space shuttle Discovery boasted a soda machine in 1995.
But there would be serious digestive problems if an astronaut actually drank it on board, as in microgravity the bubbles grow to enormous sizes, resulting in a frothy drink with a significantly greater gas-to-volume ratio than its Earthbound counterpart. “Unable to escape the fluid in the digestive system, the gas would cause painful bloating in the astronauts’ stomach and intestines,” the authors write. “For relief, you could only burp, but in the microgravity environment, the burp was often wet, just like the experience of acid reflux.”
To check. No champagne or soft drinks in the room.
DOI: Physics today2018. 10.1063/PT.3.4069 (About DOIs).