December 9, 2023

Beer and peanuts have long been a match made in heaven, and it’s hard to pin down exactly when the divine union took place.It was officially commercialized in the US in 1937 with the rather ingenious Beer Nuts brand and has been enjoyed by scientists for almost as long conduct human trials Attempts to explain this precious union.

New research examines peanuts’ ability to temporarily defy physics — specifically Archimedes’ principle of buoyancy — when dropped into a glass of beer. Because peanuts are denser than beer, it should sink and stay below, but it will rise again, then sink, then rise again, performing a “dance” fueled by bubbles until it runs out of gas.

Why drop peanuts (peanut) in beer? This is also a good question. But that’s what Luis Pereira, a Brazilian researcher who observed in a bar in Argentina, may help us understand other ways the density law is twisted in nature by studying the science behind it.

When peanuts are put in beer, it sinks to the bottom of the glass. But soon, tiny bubbles of carbon dioxide coat the surface of the nut, acting like a flotation device, dragging the nut upwards before bursting when it hits the surface.

As the nut sank, Pereira noticed it became a nucleation site. Beer containers can also create nucleation sites that encourage carbon dioxide bubbles to gather and rise up the liquid, maintaining carbonation.

At this point, the peanut dance is not complete as it rolls across the surface, popping any attached air bubbles. It sinks again, then collects new air bubbles and repeats. Lifespan and strength depend on the contact angle interaction between the bubbles and the peanut, and will eventually stop when the CO2 runs out (or, more likely, you get tired of watching the nuts slosh in the liquid and drink the beer instead) .

Graphical description of the peanut dance
Graphical description of the peanut dance

Using a series of experiments by researchers in Germany, Britain and France that put roasted peanuts in lager beer, the team dubbed this “dance” the “beer-gas-peanut” system and said it could be used to Understand similar phenomena to phenomena in nature and industry.

For example, they suggest, it could help explain why Dense magnetite rises to higher layers below the Earth’s surface, despite being surrounded by crystalline magma, and likely with similar contact angles.

The researchers hope to expand their research to examine the phenomenon in other types of containers and beer brewing, proving in the process that scientific data collection isn’t always tedious work.

“This research has a legacy, and the observation of bubble dynamics in beer is a rich topic that deserves repeated study,” they note.

The study was published in the journal Royal Society Open Science.