Beer Science

• The distinguishing feature as to whether beers should be served cold or warm hangs on the schism between ale and lager. The former dates back to the Bronze Age, at least to 2,000 BC, and involves top-fermenting yeast and plenty of hops that are brewed warm, between 59 and 77 degrees Fahrenheit. Lagers, on the other hand, are a relatively recent invention, dating only to the mid-19th century, and use bottom-fermenting yeast brewed at lower temperatures, from 41 to 50 degrees. As a rule of thumb, dark, spicy ales demand warmer temperatures to release their flavors, while lagers are at their most refreshing when their clear, crisp quality is accentuated by colder serving temperatures.

Ice Cold

• Since lager constitutes around 90 percent of the beer market at the time of publication, the typical beer is served as an ice-cold thirst quencher. Most draft beers exit the pump at around 38 degrees, with many subsequently going into chilled glasses, while bottled beer manufacturers have increasingly pushed for their beers to be served with a frosting of ice, even creating labels that indicate when the beer is at its optimal temperature. For light and low alcohol beers, a temperature between 35 and 40 degrees will slake the thirst on a hot day without compromising flavor. Critics of the ice-cold beer trend, however, point out that many commercial pilsners are so thin on complexity and aroma that serving them cold is a ploy to conceal their lack of flavor.

Cellar Temperature

• Between chilled and room temperature, brewers exploit a distinct third band between 50 and 55 degrees, which reflects the cooled environment of the traditional cellar. This is the ideal temperature at which to serve traditional ales, including English bitters and Indian Pale Ales, or IPAs. Traditionally, these ales are stored in casks rather than pressurized kegs and are gravity- or hand-pumped from a storage cellar. Serving ales at cellar temperature allows the hoppy aromas to establish themselves and the subtle bitterness to compete with flavors ranging from fruit and herbs to citrus and spice.

Warm Brew

• Stouts and cask ales are usually served at room temperature, since their higher alcohol content and fuller flavor demand savoring rather than gulping. Belgian strong ales, for example, reveal their true nature between 55 to 60 degrees, while warmer temperatures facilitate the formation of the all-important foam head on a perfect stout. Nevertheless, the hugely successful rebranding of Guinness as an ice-cold thirst-quencher rather than just a warm tap-room tipple has proved that chilling stout is the most effective way of luring drinkers away from lighter beers without drastically compromising the end product.

Successful Variations

• Ultimately, experience proves that the rules for serving beer are open to experimentation. Only the most resilient purist could be repulsed by the Mexican Michelada, a refreshing cocktail of beer, ice and a dash of lime, which turns out to taste no more watered-down than a soda. At the other end of the spectrum, iced light pilsner drinkers would be stunned to learn that hot mulled beer was ubiquitous in Europe from the 1500s to the 1800s. The ale is warmed with spices, including nutmeg, cinnamon and ginger and a dash of added sugar, to counter the extra bitterness.