Scientists Can Finally Explain the ‘Bubble Cascade’ in a Pint of Guinness
This knowledge won’t make your beer taste any different, but it could make for a decent pub discussion.
Guinness is one of the world’s best-known beer brands, and its legacy has endured for plenty of reasons like its Irish heritage, its dark stout style in a global beer scene dominated by pale lagers, and its iconic nitrogen pour which results in a mesmerizing effect of cascading bubbles. Plenty of drinkers have watched a Guinness transform before their eyes and thought, That’s pretty cool, but a team of scientists recently decided to dig even deeper and actually determine why.
Researchers from Japan’s Osaka University and Kirin Holdings Company (which owns plenty of beer brands and distributes Guinness for spirits giant Diageo in Japan) say they’ve finally unlocked the mechanism that causes the “bubble cascade” beer drinkers are used to seeing in a pint of Guinness — a phenomenon that their paper states “is a frequently observed phenomenon on pub tables” but that has resulted in a number of explanations with “inconsistencies.” One of the problems, according to Osaka University, is that Guinness is an “opaque and dark-colored” beer which makes observation more difficult. So for their research, the team instead created a transparent “pseudo-Guinness fluid” to make measurements easier — a kind of “Crystal Guinness,” you could say.
In the end, Osaka University explains that the cascading appearance of a Guinness is caused by “a bubble-free fluid film flowing down along the wall of the glass,” a phenomenon “analogous to roll waves commonly observed in water sliding downhill on a rainy day.”
Granted, knowing the very specific bit of science probably won’t help you enjoy your beer, but lead author Tomoaki Watamura says plenty of other applications exist. “There are a large number of small objects in nature, such as fine rock particles transported from rivers to the sea and microorganisms living in lakes and ponds. Comprehending and regulating the movement of small objects is important in various industrial processes as well,” he explained in a statement. “Our research results will be useful in understanding and controlling flows of bubbles and particles used in industrial processes as well as protein crystallization and cell cultivation used in the field of life science.” Plus it gives you one more thing to talk about in the pub while you’re drinking a Guinness.
Meanwhile, Guinness isn’t the only alcoholic beverage that recently had this kind of phenomenon explained. Earlier this year, a researcher at UCLA unveiled her groundbreaking explanation into why wine has “legs.”