If you’ve ever been hit by a flying champagne cork, you’ll be painfully aware of the pressure inside a bottle of fizz. And that pressure inside (and outside) the bottle has captured the imagination of champagne innovators.
“Every year we carry out many tests to adapt the pressure to the vintage,” says Jean Baptiste Lécaillon, chef de cave at Louis Roederer. “We have lower pressure – so smaller bubbles – (because) we want a seamless and soft mousse.”
The pressure in a bottle of champagne is usually around 6 bar, or three times the pressure of a car tire. But Louis Roederer champagnes can range from 6 to 4.5 bar. “The more acidity you have in the wine, the more aggressive the feeling of the bubbles… This is also why we are on the low side,” explains Lécaillon, “especially with Cristal, which is often non-malo (referring to malolactic fermentation) and low pH.” The recently released Cristal 2015, he says, “is a great example of this feather-light mousse… It is delicious, effortlessly intense and delicate at the same time.”
You only need to have a basic understanding of physics to realize that storing champagne at higher temperatures will increase the pressure inside. But scientists were surprised to find that when a bottle stored at 20 degrees Celsius (well above cellar temperature) was uncorked, the speed of the gas expelled from the bottleneck temporarily reached almost Mach 2 – twice the speed of sound.
The ballistics of bubbles
Researcher Gérard Liger-Belair, professor of chemical physics at the University of Reims Champagne-Ardenne, compares this phenomenon “to what happens with the exhaust gases of rocket plumes.” The pressure causes the CO2 freeze and turn into dry ice when suddenly released, creating a plume at the bottle opening.
Liger-Belair is a specialist in champagne and effervescence, and author of Uncorked: the science of champagne. But he hopes the findings, published in a academic journal last year will also have applications in the field of ballistics and missiles.
The pressure in a champagne bottle decreases over the years, resulting in smaller and sparser bubbles – and that more composed, rather calmer character can often be part of the charm of a long-maturing cuvée.
In the name of research, Vincent Chaperon, Dom Pérignon’s cellar master, once attempted to revive the bubbles in a bottle of Dom Pérignon Plénitude 2, which is aged on its lees for 15 to 20 years, or about twice as long as a flagship D.P. He won’t say how he did it (SodaStream? Aarke?), but he admits that the result was ‘inharmonious – not good’.
“With Dom Pérignon, there is not that much difference in size and number of bubbles from one vintage to another,” he adds. “Yet I believe that the way you feel the bubbles in your mouth is representative of the balance of the wine. As if the bubbles carry the entire personality of each vintage.”
He compares Dom Pérignon 2012: “You immediately feel the bubbles with the first ‘attack’ of the wine. They tickle your palate with precision and energy.” Then, with the recently released Dom Pérignon 2013: “The feeling of bubbles comes later, in the middle of the mouth. The sensation is much milder, caresses your palate and reveals the elegance of 2013.”
Send the Fizz robot
Bubbles are also experienced psychologically. Sigfredo Fuentes, associate professor of digital agriculture and food/wine sciences at the University of Melbourne, found that people associated seeing the intensity and longevity of bubbles with better quality champagne, even if it was just a cheap splash that had been sonically bubbled .
Based on these insights, Fuentes’ team created the FIZZeyeRobot, a machine that pours and measures the lifespan of foam and the gases released. AI software predicts how this will affect the release of flavor compounds, and in turn how potentially tasty the drink will be.