A physicist has determined the ideal shape for a cold beer glass.

Previous studies and numerous anecdotal evidence suggest that beer consumers prefer their drink cold — typically as cold as possible. Many beer enthusiasts also enjoy drinking from a clear glass — this allows them to monitor the remaining volume, observe the color, foam, and bubbles.

Unfortunately, clear glasses tend to warm up the drink quickly. As a result, beer glass manufacturers have developed a variety of designs aimed at maintaining as much coldness for as long as possible. They have also adapted the shapes of the vessels for different types of beer to enhance the olfactory experience for consumers.

Claudio Pellegrini, a professor of thermal and hydrodynamic sciences at the Federal University of San Juan del Rey in Brazil, calculated the optimal glass shape to keep beer cold for the longest time. The article is published on the preprint server arXiv.org.

Pellegrini started this work to demonstrate to students how physical and mathematical knowledge can and should be applied in real life to solve everyday problems. Explaining the "practical significance" of the knowledge gained is an important aspect of higher education. And a challenging one. It is beneficial for students to be given realistic examples and practical tasks related to their own lives to maintain interest in their studies. This could involve problems like optimal pizza cutting or calculating the ideal beer glass, as in this case.

The physicist did not consider external factors such as the heat from the hand holding the glass or the types of glass used. Instead, he focused on the shape of the glass to determine the rate of heat transfer.

The glasses in the calculations had an insulated base, allowing for temperature changes in the liquid only from the top and sides. An assumption in the study was also a fixed initial temperature of the beer and that the glass would have negligible thermal resistance. This scenario ensured that changes in heat transfer would be a direct result of changes in shape.

After completing the calculations, Pellegrini found that the best shape is a glass with a small base that widens towards the top, such as a pilsner glass.

The researcher noted that the truly best result for keeping beer cool would be a small, faceted glass with a capacity of up to 350 milliliters. In this case, the contents are consumed in one or two quick sips. However, the physicist insists that drinking beer in such an "ugly" manner from mediocre vessels completely ignores the essence of drinking.