American brown ale,
From The Oxford Companion to Beer
a dark and richly malty ale often well-seasoned with hop flavor and aroma, evolved most recently from the classic English brown ale style. Notable examples include the Pelican Pub & Brewery’s Doryman’s Dark Ale, Brooklyn Brown Ale, Bell’s Best Brown, and North Coast Acme Brown.
American brown ale traces links to English brown ale, mild ale, 18th-century brown porter, and even the stylistically undefined brews of 17th-century England. This style also shows similar influences to other Americanized styles such as American pale ale and American amber ale.
Robust expressions of malt, mouthfeel, and alcohol content typify the style. All three of these traits arise from the type and quantity of malts selected and their use in brewing. Built on a base of two-row North American malt like other Americanized beers, this style finds its distinctive traits in the specialty malts employed. Nearly all formulations add medium to dark crystal or caramel malts, which lead to caramel to toffee flavors in the finished beer. To supplement this, darker grains such as chocolate malt, black malt, or roast barley are often added in small proportions to increase color and contribute chocolate or lightly roasted flavors. Various other caramel and toasted malts may be added to enhance these flavors and extend the richness and complexity of the malt palate.
The extensive use of specialty malts, combined with higher mash temperatures, leads to a medium to medium-full mouthfeel in the finished beer. Despite this, sufficient malt is used to reach alcohol contents that range from 4.3% to 6.2% ABV.
The finished beer color results primarily from the grist formulation. Paler examples stick to smaller quantities and lighter types of specialty malts resulting in amber-colored beers (perhaps as low as 15 Standard Reference Method); darker formulations give a dark brown color (up to 35 SRM).
While richly malty, this style—like American pale and amber ales—often exhibits substantial hop character as well. Both formal style guidelines and actual commercial examples indicate that high levels of aroma and flavor hops occur. But unlike some other Americanized styles, these hop expressions may be subdued. Furthermore, the herbal, flowery, or spicy traits of English or noble hops can be substituted for the citrus, piney flavors of American varieties. Thus, American brown ale varies more widely in hop expression than do the related pale and amber ales.
Bitterness levels also vary, but on the whole they tend to provide a solid balance to the malt, keeping sweetness in check without distracting from the rich flavors offered there. Measured levels range from 20 to 40 IBUs.
This definition is from The Oxford Companion to Beer, edited by Garrett Oliver. © Oxford University Press 2012.