How do you keep a glass of beer cold for the longest time? By using science, of course. At least that’s what one researcher has focused on: he’s found the optimal barrel shape that will keep a poured beer chilled for as long as possible while you drink it.
Claudio Pellegrini, professor of thermal and fluid sciences at Brazil’s Federal University of São João del-Rei, has filtered the problem into a basic mathematical formula for various clear beer glass designs, focusing on several popular designs: the Brazilian tulip, imperial pint, American pint, Weizen glass, beer mug and the ‘super’ mug.
While Pellegrini kept it simple by eliminating variables such as heat transfer from hands or the impact of foam, he focused on the shape of the glass to determine the most efficient design for cold beer.
“In tropical countries like Brazil, a recurring problem is how to keep it cold during consumption, especially in coastal areas,” he noted.
In his work he focused on the curvature of the glass, noting that people have an aesthetic preference for clear vessels and that most would have some kind of insulation at the base.
“The process here is quite simple: a beer is requested, the waiter delivers it, it is served, it is consumed. Repeat,” Pellegrini explains. “Once poured into the glass, the beer begins to exchange heat with its surroundings, a process that lasts until it reaches thermal equilibrium with the surroundings (including the glass), an outcome that no one actually wants. Depending on the initial temperature difference between the beer and the environment can make the drink unsuitable for consumption within a short time.
“In the most critical scenario, such as at the beach on a windy 38°C (100°F) day, just three minutes may be enough,” he added, “to make the beer undrinkable.”
Now the research shows that Pellegrini had to drink a few too many warm beers in his time. But it’s a fascinating study that shows how there’s more to the shape of a glass than what meets the eye.
Ultimately, his assessment of optimal minimum heat transfer settled on a form that already exists: the classic pilsner beer glass. Typically narrow at the bottom and wide at the top, with a steady curvature, this ship proved – mathematically speaking – superior to all other types.
While he acknowledged that the best glass may be so small that the beer is gone in no more than a few bites, his goal was to expose the vessel that allows you to enjoy your drink a little longer.
“Possible areas for further research include allowing the base of the glass and its body to exchange heat with the environment, including radiant heat transfer and/or conduction heat transfer through the foam,” the researcher noted.
Pellegrini also said that, aside from personal interest, he had a motive for this research: to get students more involved in an often abstract and dry area of learning.
“The primary goal, of course, was to increase engineering students’ interest in physics and mathematics,” he concluded. “However, a secondary but crucial application of the current results was to ensure the quality of our beers.”
The research has been published on the preprint server arXiv.
Source: Federal University of São João del-Rei via phys.org