I’ll admit that a frosted beer mug seems like a great idea, especially on a hot summer’s day. Many bars serve beers in chilled glasses or frosted mugs or glasses. Lest you think that a frosted glass leads to a colder beer which leads to a better tasting beer, think again. A super-chilled beer is not necessarily the best tasting beer. An ice-cold beer is a beer you cannot taste as well, and the aromatics will be dampened by the cold temperature. Regardless, though, if you enjoy a beer more when it is served in a frosted glass, then bottoms up!
It used to be very common for restaurants and bars to store beer glasses in specialized coolers which would chill them down and coat them with a layer of frost. A “frosty mug of beer” became quite literal. When most of the beer we drank in America was of the mass-produced light lager variety, this may have made more sense, and there is a lot to be said for the sensory effect of frosty cool glass of beer. As the craft beer market exploded and brewers sought to educate others on the proper temperature for serving beer, this practice became less common. The chilled glassware not only made the beer too cold but could cause ice crystals to form in the beer and condensation to occur, watering down the beer. Not only is the beer physically affected, the icy temperature inhibits the proper flavor experience.
To understand why frosted glasses affect the flavor of beer take a lesson from ice cream. Temperature affects our taste and flavor perception. If you have ever made home-made ice cream, you will notice that the ice-cream mix, be it custard based or not, will taste overly sweet before you freeze it. This is intentional, as the coldness dampens our perception of sweetness. You have to start out with a sweeter product so that it will taste sweet enough once it is frozen. Much of the same effects on flavor perception, which includes the aromatics, is at work in beer.
Our taste buds are most sensitive between 68 and 86 F. Basically, the warmer temperatures make foods and beverages taste sweeter, and since any volatile elements are more likely to evaporate, the stronger the smell. Cooler temperatures also reduce sensitivity to certain bitter tastes (alkaloids) , while actually enhancing the perception of others (phenolics).
Now, I do not buy the advice of experts that beer always tastes best between 46 and 50°F, as taste is a subjective experience, and there are many factors that determine how we perceive flavor, including temperature. There is room for personal preference when it comes to beer temperature. However, a beer that is chilled to near freezing will not taste the way it was meant to taste. For the most part, the temperature of the average refrigerator will do fine for most folks. I prefer to chill my beer just a bit more, so that it starts out colder, but warms up as a drink it.
Beer in frosted glass image © Thomaguery