Flavor

• Despite the stereotype of the frosty mug, most beer experts recommend not serving beer at low temperatures. Brewmasters and experts quoted by craftbeer.com point out that very cold liquids will numb the tongue, preventing the drinker from tasting the beer. Britain's Campaign for Real Ale goes even further, recommending that real ale (traditional, non-pasteurized beer) be served at cellar temperature, just slightly below room temperature, to allow its subtle flavors to stand out.

Brewer Recommendations

• Craft beer lovers sometimes jokingly suggest that large breweries encourage serving beer cold precisely because it masks the taste of the beer. In fact, however, even though large American breweries recommend serving temperatures colder than most craft brewers would like, they still don't endorse frosted glasses. Beer giant Anheuser-Busch does recommend chilling glasses to 20 degrees Fahrenheit, but warns that frosted glasses can affect taste or lead to a bad pour.

Contamination

• One concern expressed by many experts is that frosting causes contamination. Putting a beer glass in a freezer means that the frosting it picks up may contain flavors from food in the freezer, according to brewmaster Joe Katchever. Additionally, freezing can interfere with the disinfecting process, resulting in a glass that isn't "beer-clean." Melting frost from a glass can dilute the beer, while if the glass is very cold it can even freeze water out of the beer, causing it to separate.

Handling

• Although a frosted mug can look appealing and refreshing when it first lands on the bar, once it reaches room temperature the frost on its surface quickly begins to melt. This can result in a slippery glass that's difficult to hold on to. Relief on a hot day can quickly turn into disappointment when a slippery glass results in a messy spill. The combination of reduced flavor, possible contamination and awkward handling makes frosted glasses a bad choice for beer lovers.