The American Homebrewers Association recognizes seventy beer styles.
Here is a description of the most common beer styles:
Lager: Two different types of yeast can be used to create alcohol. Bottom-fermenting yeast that ferments slowly at a low temperature creates a smoother, mellower beer. Lager beers are light in color, high in carbonation and tend to be less alcoholic than ales. Lagers are best served chilled (about 48 °F/9 °C).
Ale: The other type of yeast rises to the top during fermentation. It also ferments more rapidly and at a higher temperature, resulting in a more aromatic and fruity product. Real ale is produced using traditional methods, without pasteurization. Compared to lagers, ales have a lower amount of carbonation and should be served at a warmer temperature (54-56 °F/12-13 °C). Strong ales should be served at room temperature.
Amber: Malty, hoppy beers have a rich golden color. They can be ales or lagers and tend to be fuller bodied due to the addition of specialty grains.
Bitter: Highly hopped for a more dry and aromatic beer, bitter is pale in color but strong in alcohol content. It’s popular in British pubs.
Dark Beer: Beer becomes darker when the barley is kilned for a longer period of time. This also creates richer, deeper flavors from the roasted grain.
Fruit Beer: Fruit may be added either during the primary fermentation or later. Fruit beer is usually made with berries, although other fruits can be used.
India Pale Ale: The name is often shortened to IPA. This ale was originally brewed in England for export to India. The large quantities of hops added were intended as a preservative and to mask potential off-flavors that might develop during the long voyage.
Mild Beer: Developed as a sweeter and cheaper alternative to dark ales and porters. Mild beer was a popular beer in the mid-nineteenth century but has all but disappeared in most pubs.
Pilsner: This is the term for the classic lager originally developed in Czechoslovakia, a pale, golden-hued, light beer after which many mass-produced American beers are modeled. Pilsners should be served very cold (43 °F/6 °C).
Porter: Very bitter, very dark, this beer was developed in England as a “nourishing” drink for manual laborers such as porters.
Stout: Very dark and heavy, with roasted unmalted barley and, often, caramel malt or sugar, stout was invented by Guinness as a variation on the traditional porter. Serve Guinness at a cool temperature (41-43 °F/5-6 °C).
Wheat Beer (Weizen): Malted wheat, in addition to barley, is used for this German style beer. Wheat beers were drunk prior to Prohibition and are experiencing a rebirth in the U.S. American wheat beers are markedly different from their German predecessors, which are “spicier.”