Ice beer is beer which is conditioned in a chilled environment, promoting the development of ice crystals which are removed, thereby concentrating the flavor and alcohol content of the beer. Ice beers are made with a lager base, and they appear in a variety of guises. German ice beers or eisbocks are very strong winter lagers with a rich, complex flavor, while North American ice beers tend to be short on flavor and long on alcohol, designed for the purpose of cheap intoxication.
The discovery of ice beer was probably a mistake, much like other discoveries in the world of beer. Lagers are traditionally aged, sometimes in very cool environments, and according to legend, some German beer makers were dismayed to find ice in their lager one day, so they removed it, creating the first eisbock. German ice beers are dark, thick, and very strong, with a malty flavor and a formidable alcohol content, and they were designed for drinking in the winter, when some people enjoy hearty beers with a filling texture.
Canadian and American brewers eventually picked up the idea, developing their own take on ice beer. North American ice beers tend to be slightly sweet, with an increased alcohol content and a pale flavor. These beers are often very cheap, marketed in packaging which is designed to appeal to heavy drinkers, and some breweries have been criticized for the marketing tactics used to promote ice beer.
North American ice beers are light enough to be consumed in the summer months, and their alcohol content varies, depending on the distillery. Some North American ice beers are actually not terribly alcoholic, while others are markedly stronger than beers which have not been subjected to the chilled conditioning process. Several companies also make “light” versions which are lower in calories, for beer drinkers who are concerned about their figures.
The process involved in the conditioning of ice beer is a classic example of fractional distillation. In fractional distillation, a fluid is chilled or heated to separate its components. In the case of ice beer, the water in the beer freezes before the alcohol, creating ice chips which can be removed from the beer, leaving the alcohol behind. Enterprising beer drinkers can even create their own ice beer by chilling beer in a carefully controlled environment, removing it before it freezes completely so that it can be strained to remove the ice.