Why Peanuts ‘Dance’ When Dropped in Beer: An Explanation by Scientists

In a pint of beer, peanuts first sink to the bottom before rising to the top and “dancing” in the glass. In a recent research released on Wednesday, scientists delved deeply to learn more about this occurrence in an effort to better comprehend mineral extraction or bubbling magma in the Earth’s crust. Lead author of the study and Brazilian researcher Luiz Pereira told AFP that the inspiration for the study came to him while studying Spanish in Buenos Aires, Argentina.

According to Pereira, adding a few peanuts to drinks was “bartender thing” in the city.

The peanuts initially settle to the bottom of the glass since they are denser than the beer.

Then, each peanut becomes a “nucleation site,” as the term is used. On their surface, hundreds of small carbon dioxide bubbles emerge, functioning as buoys to lift them upward.

According to Pereira, a researcher at the Ludwig Maximilian University of Munich in Germany, “the bubbles prefer to form on the peanuts rather than on the glass walls.”

The bubbles burst as they reach the surface.

The dance continues until the carbon dioxide runs out or someone breaks it by drinking the beer. The peanuts then plunge down before being driven back up by newly generated bubbles.

The group of scientists from Germany, Britain, and France undertook a number of tests to see how roasted, shelled peanuts fared in lager-style beer.

– Up next: more brews

Two important components of what the researchers called the “beer-gas-peanut system” are discussed in the study, which was published in the journal Royal Society Open Science.

They discovered that a bubble was more likely to develop and expand if there was a bigger “contact angle” between its curvature and the peanut’s surface.

However, it must not expand too much; the optimal radius, according to the research, is less than 1.3 millimeters.

“By deeply researching this simple system, which everyone can grasp,” Pereira said, “we can understand a system” that might be valuable for business or understanding natural events.

He explained that the flotation process, for instance, was comparable to the method used to remove iron from ore.

A mineral, such as iron, “will rise because bubbles attach themselves more easily to it, while other (minerals) sink to the bottom,” he added. Air is then carefully pumped into the mixture.

The same mechanism may also account for why magnetite appears in greater levels of crystallized magma in the Earth’s crust than is typical, according to volcanologists.

Magnetite should be near the bottom since it is denser, similar to peanuts. However, the researchers assume that the mineral climbs through the magma with the aid of gas bubbles owing to a high contact angle.

Science is, of course, never really established, especially when beer is involved.

Pereira said that scientists would continue to “play with the characteristics of different peanuts and different beers” in an effort to improve their model of the dancing peanut phenomena.