The shape of a beer glass matters a lot according to a new study. One of the most infamous and ignored problems of our time is the question of how best to keep
beer cold after it's poured into a glass.
Today, one scientist has found a solution to this problem by proposing the use of a mathematical model that determines what is the optimal shape of a beer glass that keeps beer cold. This problem is well known to many generations of beer drinkers around the world.
As soon as the beer is poured into the glass, it begins to heat up, so an important goal is to minimize heat exposure to the beer so it stays colder longer.
Typically, beer drinkers solve this problem by using foam sleeves to insulate the mug's heat and adding handles to reduce hand contact. But Claudio Pellegrini of the Federal University of Sao Joao del Rey in Brazil took a different approach by redesigning the glass itself without adding any additional insulating layers.
Heat transfer
The main challenge is to create a shape that minimizes heat transfer while keeping the design practical for normal use. Part of the challenge, therefore, is to understand the rate at which heat is transferred into glass of a particular geometric shape.
But Pellegrini's problem was much more difficult: to find a geometry that minimizes the heat transfer rate. In other words, an inverse optimization problem.
The scientist began by modeling the glass as a smooth curve rotating around a vertical axis to form a "body of rotation" with a defined base radius, height, and ratio between the base and top opening.
Photo:schott-zwiesel.ru
The researcher postulates that the base is insulated and the fluid maintains the same temperature and composition throughout and that the glass has negligible thermal resistance. This postulate gives assurance that the main factor determining heat transfer is the shape of the vessel.
Using this approach, Pellegrini found that perhaps the optimal beer glass has a narrow base and gradually widens toward the top, which also allows the user to drink comfortably. He says most traditional beer glasses already have these characteristics - for example, the Tulip glass, Imperial pint glass and Weizen Beer glass, which have a wide neck and narrower base.
However, Pellegrini's approach is not without some limitations. The functioning of the optimization algorithm will be possible for certain values of the base radius, the glass height and the ratio of the base radius to the hole radius. But because of this, one best configuration of these values cannot be determined. Thus, the solution is several shapes with relatively small differences.
Flavor molecules
Of course, there are other factors that determine the shape of a beer glass. For example, the size and shape of the top of the glass determines the amount of foam that forms when beer is poured. And because the foam traps flavor molecules, it affects the drinking experience. For example, many Belgian beers are served in specially shaped glasses, which helps to create a unique experience.
Pellegrini laments the cheap and therefore most common beer glass in Brazil, known as the Nadira Figueiredo glass. According to him, it has a volume of only 190 milliliters, which is little more than a couple of sips.
"It keeps the beer cold through the most primitive of processes: because of its small capacity, the beer is consumed so quickly that it doesn't have time to heat up," he says. The researcher hopes that this glass will not catch on in other countries.