Shulou(Shulou.com)11/24 Report--

Open the bottle, raise the glass, and drink to physics and chemistry and the good things.

In a laboratory in the French wine country, a group of researchers carefully installed an ultra-high-speed camera. Like many good scientists, they devote themselves to solving the secrets of the universe and seek to describe the material world in the language of mathematics, physics and chemistry. Their subjects were bubbles in champagne.

Gerard é rard Liger-Belair, a chemical physicist who heads the eight-member team on bubbles and champagne at Lance University, probably knows more about champagne bubbles than anyone else on earth. Since his doctoral thesis in 2001, Liguel Belle has focused on blistering inside and above the cup. He has written more than 100 papers on the subject, including an in-depth study of champagne and sparkling wine in the Annual Review of Analytical Chemistry in 2021, as well as a best-selling book, Open the bottle: the Science of Champagne.

"when I was a kid, I was obsessed with blowing and watching soap bubbles," Ligill Belle recalls. "this obsession lasted all the time and supported me to do a lot of practical work. Bubbles have many attractions, not just the fun of sparkling wine." Liguel Belle shows aerosols formed by tiny bubbles in sea fog that burst and rises into the sky, and shows how the ocean affects cloud formation and climate change. He even helped astronomers determine that some of the mysterious highlights in radar scans of Saturn's moon Titan may be centimeters of nitrogen bubbles burst from its polar ocean surface.

Ligill Belle is happy to focus on bubbles in champagne and other sparkling drinks, including cola and beer, over the past 20 years. His lab studied all the factors that affect bubbles, from the type of cork to the composition of the wine to the way drinks are dumped. They studied how carbon dioxide bubbles affect taste, including the size and number of bubbles and the aromatic compounds that evaporate into the air above the cup.

To find out, they turned to gas chromatography and other analytical techniques. And, in the process, they took some eye-catching photos. Other people around the world have also set their sights on bubbles, even invented robots to pour wine steadily, and began to pay attention to the psychology when we enjoy bubbles.

Champagne researcher Ligill Belle pointed a high-speed camera at the glass to capture the change and rise of bubbles. According to the champagne legend from grapes to glasses, Dom Pierre Pier P é rignon, the owner of the cellar of a monastery in the Champagne region of France, drank the first occasional sparkling wine and sighed, "I'm drinking stars!" It turns out that this may be fictional. The earliest sparkling wine may have come from another monastery in France, while the first scientific paper on foaming came from the Englishman Christopher Merret, who proposed the idea to the newly formed Royal Society of London in 1662, years before Perignon became owner of the wine cellar.

The traditional method of producing champagne includes the first fermentation of grapes to produce base wine, followed by the addition of sugar cane or beet sugar and yeast for a second fermentation. Then, the secondary fermented wine is kept for at least 15 months (sometimes decades), during which the dead yeast cells change the taste of the wine. The dead yeast is frozen into a stopper in the bottleneck, then the cork is pulled out and the yeast is removed. Some of the gas in the drink will be lost in the middle.

The wine is rebottled and sometimes extra sugar is added, creating a new balance between the air layer and the liquid layer in the bottle and determining the final amount of carbon dioxide dissolved. For those who want to see math problems, there is an equation to describe the gas content at each stage.

A cork pops up from a champagne bottle. Scientists have found that a high-quality cork made of small particles with a lot of adhesive can keep gas in the bottle for at least 70 years.

Of course, the taste of the final product depends largely on the raw materials. "grapes are at the core of wine quality," says Kenny McMahon (Kenny McMahon). He is a food scientist who studied sparkling wine at Washington State University before starting his own winery. The taste of the wine also depends largely on how much sugar is added in the final stage. McMahon said: "in the Roaring twenties (1920s), American champagne was really sweet. Modern tastes change a lot, and vary from country to country."

But bubbles are also important: proteins in wine, including those from yeast cells, fix smaller bubbles, creating an ideal "mousse" foam at the top of the champagne glass, making a clearer popping sound in the mouth. According to Sigfredo Fuentes of the University of Melbourne, most of the average consumer's impression of sparkling wine comes from an unconscious assessment of bubbles.

Fuentes, who studies digital agriculture, food and wine science, said: "you can basically judge whether you like a champagne by your first visual reaction. The effect is so powerful that people like a cheap, airless wine that temporarily bubbles with sound waves before pouring, and people are even willing to pay more for the wine, "he said with a smile." for this really shoddy wine, it can sell for $50. "

Black-and-white photos of champagne foam. The foam at the top of the champagne glass is essential for drinkers' enjoyment, but too much carbon dioxide can irritate the nose. In general, in order for the drink to have the ideal foam burst taste and carbonated taste, the drink needs to contain at least 1.2 grams of carbon dioxide per liter of liquid. But too much carbon dioxide is not appropriate. More than 35.5% of the carbon dioxide in the air in the cup irritates the drinker's nose, causing an unpleasant tingling sensation. The irritation at the champagne flute may be even greater, because the concentration of carbon dioxide above the liquid in the champagne flute is almost twice that of a wide-mouthed butterfly cup. If poured out of a chilled bottle, it is less irritating than a warm bottle.

Liguel Belle's team found that a good cork (made up of small particles held together by a lot of adhesive) can keep the gas in the bottle for at least 70 years. After that, the drink became insipid. A bottle of champagne that has been sleeping under water for more than 170 years is a case in point when archaeologists found it on a shipwreck in 2010.

Ligill Belle and his colleague Clara Silindler (Clara Cilindre) received several milliliters of this precious "elixir" to study. In 2015, they and colleagues said the wines had some interesting properties, including an unusually high iron-to-copper ratio (possibly from nails in aged barrels, or even pesticides from grapes). They also have a lot of sugar, but the alcohol content is surprisingly low, perhaps because of late fermentation at cooler temperatures than usual. Although Liguel Belle and Silindler regretted not having the chance to taste their samples, others used words such as "tacky" to describe it.

A bottle of champagne covered with mud lies in the wreckage of an underwater shipwreck. The 170-year-old bottle of champagne is disappointingly mundane and tastes "tacky". For a more common bottle of ordinary champagne, even the method of pouring the wine can have an effect on the bubbles. If you pour 100 milliliters of champagne directly into a vertical champagne flute, Liguel Belle calculates that there are about a million bubbles in the glass. However, the "beer-style pouring method" that falls gently from the side of the glass will add tens of thousands of bubbles. "if not handled properly, there will be a huge loss of dissolved carbon dioxide," he said. " Rough spots inside the glass can also help form bubbles, and some glassmakers etch shapes inside the glass to help with the process. To avoid introducing bubble-producing surfactants, some people don't even wash their cups with soap, McMahon said.

Champagne Taste Test Fuentes is pursuing another perspective of commercial application. His team created FIZZeyeRobot--, a simple robotic device (prototype made of Lego bricks) that can be used to pour wine steadily. The robot uses a camera to measure the volume and lifespan of foam at the top of the glass, and has metal oxide sensors to detect levels of carbon dioxide, alcohol, methane and other substances in the air above the glass. The team is using artificial intelligence-based software to use these factors to predict the aromatic compounds of the drink itself and, importantly, to predict the taste of the wine. (most of the study was conducted on beer because it is cheaper and faster to make, but it also applies to champagne.)

"We can predict how different consumers will accept sparkling wine, whether they will like it, and why they will like it," Fuentes said. " The prediction is based on the team's own tasting preference data sets, as well as biometric techniques, including body temperature, heart rate and facial expressions. Using this information, he says, you can determine the best time for any sparkling wine to be placed with dead yeast to maximize the production of a good drink. He expects the system to be put into commercial use in 2022.

Of course, human taste is different and can be deceived. Many studies have shown that the wine tasting experience is deeply influenced by psychological expectations determined by the appearance or environment of the wine, from the companion to the lighting and music of the room. However, Liguel Belle has developed a personal preference for aged champagne (aged wines tend to contain less carbon dioxide) through decades of experience, at temperatures close to 12 degrees Celsius. Gently pour into a large tulip glass (more traditionally used in white wine) and not too full.

"since I became a scientist, many people have told me that I seem to have found the best job in all physics because my career revolves around bubbles," he said. "I work in a lab with top champagne." I agree with this, "but his real professional pleasure, he added," since I still have a childlike obsession with bubbles as I did when I was a child, this love of bubbles has not yet been burst. "

Author: Nicola Jones

Translation: Nuor

Revision: Tibetan idiots

Original link: Champagne bubbles: the science

This article comes from the official account of Wechat: Institute of Physics, Chinese Academy of Sciences (ID:cas-iop), author: Nicola Jones

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