The fascinating science behind champagne bubbles is something we really should take a little time to appreciate as we celebrate the best of what this year has given us and the hopes for the upcoming new year.
Champagne has marked the holiday season all over the globe for centuries now, with almost everyone imbibing at least one glass of the sparkling wine, especially on New Year’s Eve every year.
Of course, Champagne, France is the only region in the world which can now legally call its fizzy wine “champagne,” and it is there that researchers are still on a quest to find out all the scientific intricacies of just how these bubbles that tickle the nose are created.
Champagne bubbles are the hallmark of every celebration
Gérard Liger-Belair, who earned his doctorate in the field of the effervescence of champagne, has been on a quest to fully understand all the science behind these bubbles that add so much festivity to every celebration.
And there’s a lot to study since as many as two million bubbles of carbon dioxide can form in every glass.
A chemical physicist, Liger-Belair is the head of the eight-member “Effervescence & Champagne” group at the University of Reims Champagne-Ardenne. He is likely the foremost authority on champagne effervescence on the planet, according to Knowable magazine.
So far, he has authored more than a hundred technical papers on champagne in journals such as the Annual Review of Analytical Chemistry, as well as a popular book, titled Uncorked: The Science of Champagne.
Liger-Belair tells reporters “When I was a kid, I was entranced by blowing and watching soap bubbles.” This has led to his groundbreaking work not only in the realm of champagne, the iconic product of the vineyards of central France, but the bubbles that explode into the air in sea spray and, incredibly, the origin of strange spots on Saturn’s moon, Titan, which may be tiny nitrogen bubbles.
But when he is focused on champagne, Liger-Belair investigates all the factors that go into the formation of its fizzy bubbles, including the type of cork in the bottle to the importance of the different ingredients in wine, and even to how the drink is poured.
Champagne bubbles, which are comprised of carbon dioxide, do affect the taste of each brand of the product, and the size and number of bubbles as well as the aromatic compounds sent into the air above the glass make a difference in our taste experience.
“I am drinking the stars!”
Liger-Belair and his team use gas chromatography along with other high-tech methods to try to parse out just what is going on with champagne.
Like so much in history, it may be just an entertaining story that Dom Pierre Pérignon, a monk who was the cellar master of an abbey in Champagne, France, drank the first known sparkling wine, which was created by accident, and exclaimed: “I am drinking the stars!”
No one will ever know for sure, but the sensation is a striking one, and it is a certainty that the first-known sparking wine was produced in France.
Champagne production requires two separate fermentation processes
Like most other traditional wines, grapes are first fermented to produce a base wine, but with champagne, cane or beet sugar and yeast is then added, and the mixture is allowed to ferment a second time, for at least fifteen months and sometimes for decades.
The dead yeast that is still in the bottle at that time is then removed by freezing it into a plug in the neck of the bottle and popping it out, but some of the fizziness is lost that way.
The wine is then corked again and sometimes more sugars are added; a new equilibrium is soon established between the air space and the wine, which is the final determinant for the final amount of dissolved carbon dioxide. It will eventually explode so deliciously when we drink it.
Of course, the all-important cork has been studied extensively in France, the home of Champagne. Liger-Belair and his colleagues now know that a good-quality cork will hold the explosive gas in a champagne bottle for at least seventy years.
Any time afterward and the drinker will be very disappointed, tasting a very flat wine with few bubbles at all, much like the champagne that was found in a shipwreck off Finland 2010 after 170 years underwater.
Proteins that exist in the wine, produced in part from the yeast, stabilize smaller bubbles that make up the “mousse,” or foam, that forms at the top of the glass and create a sharper “pop” in our mouths. And these bubbles are all-important.
“You basically like—or not—a champagne or sparkling wine by the first reaction, which is visual,” says the University of Melbourne’s Sigfredo Fuentes, an expert in the science of food and wine.
A typical bottle of champagne must hold at least 1.2 grams of carbon dioxide per liter of liquid to give it its needed sparkle and bite from carbonic acid. Incredibly, however, there can be too much of a good thing; more than 35.5 percent of carbon dioxide in the air within the glass will create an unpleasant tingling sensation, Liger-Belair states.
The risk for this is greater in a champagne flute in which the carbon dioxide concentration above the liquid is almost twice that of a wider, French-style coupe glass, but lower if poured from a bottle that has been chilled.
170-year-old champagne from shipwreck sweet and not very fizzy
Liger-Belair and colleague Clara Cilindre received some of the shipwreck-salvaged champagne to study in 2015. They noted that it was unusually sweet but had little alcohol—perhaps because its fermentation had taken place later in the year and at colder than normal temperatures.
The libation is all-important as well. Liger-Belair states that a hundred milliliters (about 3.4 fluid ounces) of champagne will tragically lose approximately one million bubbles if poured straight down a completely vertical flute. Using a little finesse and pouring it in a “beer put” along the side of slanted flute will save precious tens of thousands of bubbles. These “huge losses” of dissolved CO2 make your New Year’s Eve a little less sparkling.
All of these factors have “direct implications on how best to serve and taste champagne,” according to Liger-Belair. Fuentes notes that he is aware of some producers of sparkling wines—although he refuses to name them—who add egg proteins to their wine to make a festive foam that can last for up to an hour.
“We can predict the acceptability by different consumers, if they’re going to like it or not, and why they’re going to like it,” Fuentes explains of champagne industry experts.
Of course, not everyone is an expert, and most of us only indulge in real champagne on special occasions. Over the years, Liger-Belair has, as a connoisseur and scientist, come to prefer aged champagnes, which have less carbon dioxide, but which are poured as gently as possible to preserve their bubbles.
He also states that he believes 12° Celsius (54° Fahrenheit), is the optimal temperature for champagne and that it should be served in a large, tulip-shapes glass like those used for white wines. This shape and size also allows for more “head space” above the champagne in the glass.
“Since I became a scientist, many people have told me that I seem to have landed the best job in all of physics, since I have built my career around bubbles and I work in a lab stocked with top-notch champagne,” Liger-Belair admits, adding that he’d be inclined to agree.
Still, the thing that gives him the most pleasure “comes from the fact that [he] still [has] the same childlike fascination with bubbles as [he] did when [he] was a kid,” he says.