Beer is one of the oldest drinks that humans have made. And in a recent study, a pair of scientists from the Université de Reims Champagne-Ardenne have drawn attention to a dazzling event that occurs every time we pour a cold one in a glass, by focusing on a key ingredient, carbon dioxide (CO2).
Beer is a liquid supersaturated with carbon dioxide gas. While contained in a sealed bottle, a high pressure keeps CO2 dissolved in the liquid in a larger amount than would normally exist at atmospheric pressure. But when the bottle is opened, CO2 quickly escapes into the air producing a wave of bubbles and foam.
No matter if you brew it at home or buy it the bubbles of carbon dioxide in your beer can be just as important as, of course, beer taste and texture. Bubbling can impact the bite and fizziness that you experience as the bubbles pop in your mouth as you take a sip. And not only that, “[also] the visual aspect and the release of aromas above the glass,” lead author Gérard Liger-Belair said.
The scientists compared bubbling in beer with the same feature of champagne. They found that pouring a chilled Heineken over a tilted glass produced about 1.5 million bubbles – not very different from champagne, which produced slightly over 1 million bubbles. However, the number of bubbles produced was dependent on the size of microcrevices in the glass. Microcrevices are sites on the surface of a glass wall that are only visible with a microscope, and they are where bubbles originate. They can span from 1 to 10 micrometers in size, roughly as small as a grain of sand.
Another key finding was that champagne contained about five times more dissolved CO2 than beer. And surprisingly, the amount of CO2 dissolved in beer was only a little over that of carbonated water. In addition, beer bubbles were smaller than champagne bubbles and move through the drink differently. Smaller bubbles are preferred in champagne, according to Liger-Belair, “Mainly because small ascending bubbles rise more slowly which is more elegant.”
Regardless of your beverage of choice, perhaps now you will be more interested to resist your first sip of beverage to enjoy the playful and spectacular bubble dynamics in your glass.