• Champagne is traditionally made using double fermentation of grapes.
• Small bubbles are stabilized by proteins to form the mousse-like foam at the top of champagne glasses.
• There are many factors that influence the number of bubbles in each glass, including ingredients and pouring technique.

A group of researchers carefully places an ultra-high speed camera in a laboratory located in the heart France's wine country. They are dedicated to unraveling the secrets of the universe, and seek to explain the material world using mathematics, physics, and chemistry. Their focus is on champagne bubbles.

Gerard Liger Belair, a chemical physicist, is head of the University of Reims Champagne Champagne-Ardenne's eight-member team "Effervescence & Champagne". He may know more about champagne bubbles than anyone on the planet. Liger-Belair's PhD thesis was in 2001. Since then, he has been focusing on the sparkling fizz inside and beyond a glass. More than 100 technical papers have been written on the topic, including an "Annual Review of Analytical Chemistry", a 2021 deep dive in champagne and sparkling wines and a popular book entitled "Uncorked: The Science of Champagne".

Liger-Belair stated that as a child, soap bubbles fascinated her. This fascination has remained, along with a host more practical works: There are many good reasons to be fascinated in bubbles. They have many benefits that go beyond sparkling wine. Liger-Belair helped to determine which aerosols are released into the atmosphere by tiny bursting bubbles from sea spray. This has an impact on the ocean's role as a catalyst for cloud formation and climate change. Liger-Belair even helped determine that the mysterious bright spots seen in radar scans of Saturn’s moon Titan might be centimeter-sized nitrogen bubbles exploding at its polar seas.

Liger-Belair's 20-year history of research has been devoted to the bubbles found in champagne and other fizzy drinks like cola and beer. His lab studies all factors that influence bubbles, including the type of cork and wine ingredients as well as how the drink is served. These carbon dioxide bubbles can affect taste by affecting the size, number and composition of the aromatic compounds that are released into the atmosphere above the glass.

They have used gas chromatography and other analytical methods to find answers. Along the way, they have captured some stunning photos. Many others around the globe have also turned their attention to bubbles. They even invented robots that could produce consistent pours and are now focusing on the psychology behind how we enjoy fizz.

Champagne made from grapes to glass

Many believe that Dom Pierre Perignon was a monk who served as cellar master at a Champagne abbey. He drank the first accidental sparkling wine and declared, "I am drinking stars!" It turns out that this is fiction. It is likely that the original sparkler came from another French abbey. The first scientific paper on this topic was written by Christopher Merret, an Englishman who presented the idea in 1662 to the newly formed Royal Society of London. This was years before Perignon received his position.

Champagne production is traditionally done by first fermenting grapes to make a base wine. Then, yeast or cane sugar are added to the base wine and left to ferment for a second time. Double-fermented wine is left to ferment for at least 15-30 months, sometimes even decades, so that dead yeast cells don't alter the wine's taste. The dead yeast can be removed by placing a plug into the neck of the bottle and then popping out the frozen mass. Some gas is lost along the way.

Recorking the wine with sugars is done to create a new equilibrium between the air and the liquid inside the bottle. This determines the final amount dissolved carbon dioxide. For those who are interested, there are equations that describe each stage's gas content.

The taste of the final product is largely dependent on its ingredients. Kenny McMahon is a food scientist who studied sparkling wine at Washington State University before starting his winery.

It also depends on the amount of sugar added to the final stage. McMahon explains that champagnes in the United States during the Roaring Twenties were very sweet. Modern tastes are different and can vary from one country to the next.

The bubbles are equally important. Proteins in wine, such as those from exploded yeast cells, stabilize the smaller bubbles. This creates the desired mousse foam at the top and sharper pop in your mouth. According to the University of Melbourne's Sigfredo fuentes, the majority of amateurs' impressions of sparkling wines come from their unconscious perception of the bubbles.

Fuentes, a researcher in digital agriculture, wine science, said that you can determine whether or not you like a sparkling wine or champagne by their first reaction. Fuentes has discovered that this effect is so strong that people will rate cheaper, sparkling wines that have been made bubbly with sound waves right before they are poured. The sonically bubbled wine was even more popular. He said, "It went up for really bad wines to 50 dollars."

To give the bottle the sparkle and bite of carbonic acid, it should contain at least 1.2g CO ₂ per 1 Liter of liquid. There is a limit to how much CO ₂ a glass can hold. Anything higher than that will cause irritation and tingling in the nose. A flute has a higher risk of irritation because the CO ₂ above the liquid is almost twice as high than in a French-style coupe. It also has a lower concentration if it is poured from chilled bottles than from a warm one.

Liger-Belair's research team discovered that good cork, which is made of small particles and a lot adhesive, will keep the gas in the bottle for at most 70 years. After that time the beverage will become disappointingly flat. After 170 years of submerged life, champagne bottles were found in a shipwreck in 2010.

Liger-Belair received a few milliliters from this elixir, along with Clara Cilindre, his colleague. According to colleagues, the wines showed some unusual properties in 2015. This included a high level of iron and copper, possibly due to nails used in barrels or pesticides applied to the grapes. The wines also contained a lot sugar and very little alcohol. This could be due to a late-in year fermentation at lower temperatures than normal. Cilindre and Liger-Belair were unable to taste their samples. However, other people who had a chance to try it described it as "wet hair" or "cheesy".

Even the way you pour champagne can have an effect on bubbles. Liger-Belair estimates that 100ml (or 3.4 fluid ounces), of champagne can be poured into a vertical flute to create about a million bubbles. A gentler pour of beer down the glass's side will increase that number by many thousands. He said that there are huge losses of dissolved CO ₂ if it is done incorrectly.

Glass imperfections can cause bubbles to form. Glassmakers may also use rough spots to create shapes in the glass. McMahon states that some people will wash their glasses without soap to avoid bubble-popping surfactants.

Champagne taste test

Liger-Belair said that all the science has "direct implications" on how champagne should be served and tasted. McMahon is also confident that the industry has adjusted protocols to match the scientific results. However, he cannot point to any particular winery that has.

Many universities have wine departments. There's a reason. Their work helps to find financial benefits and produce fruitful applications. Fuentes claims he is aware of sparkling wine producers who add egg proteins to their wine. This creates a small bubbled foam that can last up to an hour.

Fuentes is looking for a commercial application. His team created the FIZZeyeRobot, a simple robot device that pours consistent amounts of water. It also uses a camera and metal oxide sensors to detect CO ₂, methane, and other contaminants in the air. The team is using artificial-intelligence-based software to use those factors to predict the aromatic compounds in the drink itself and, importantly, taste. This research was largely done with beer because it is easier and cheaper to make. However, the same principles apply to sparkling wines.

Fuentes stated that "we can predict the acceptance by different consumers, whether they're going going to love it or not, as well as why they'll like it." This prediction is based upon the team's own data, which includes tasters' preferences and biometrics such as body temperature, heart rate, facial expressions, and biometrics like body temperature. He says that this data can be used to determine the optimal time for sparkling wine to sit with dead yeast to maximize enjoyment. The system will be commercially available in 2022, he says.

Human palates are different and can be tricked. Numerous studies have shown that wine-tasting experiences are strongly influenced by our psychological expectations. This includes the environment, lighting, music, and company we keep.

Liger-Belair, however, has developed a preference for aged champagnes over the years. They are poured slowly to preserve the bubbles, at close to 12deg Celsius (54deg Fenheit), in large tulip-shaped glasses (more commonly used for white wines), with ample headspace.

He said, "Since becoming a scientist, many have told me that my job is the best in all of Physics, because I have built my career around champagne and work in a laboratory stocked with top-quality champagne." I'd agree.

He said that his true professional joy comes from "having the same childlike fascination for bubbles as when I was a child." This bubble-loving passion has yet to pop.