A dubbel (also double) is a Belgian Trappist beer naming convention. The origin of the dubbel was a beer brewed in the Trappist Abbey of Westmalle in 1856. Since 1836, the abbey had brewed a light-colored beer that was quite sweet and light in alcohol for consumption by the monks. The new beer, however, was a strong version of a brown beer. In 1926, the recipe was changed, and the first dubbel was released by Westmalle Abbey as Dubbel Bruin. The first written record of its sale by the abbey was on June 1, 1861. Following World War Two, abbey beers became popular in Belgium, and the name "dubbel" was used by several breweries for commercial purposes.
Dubbels are characteristically known for being dark brown in color with a strong flavor of dark fruit, including raisins, prunes, and dates. These flavors and colors are a result of the heavy addition of highly caramelized (or kilned) beet sugar, which ferments completely into alcohol, lightening the body of the finished beer and contributing to its dry finish. The caramelization of the beet sugar is also the major contributor of flavors, such as chocolatey, caramel, and nutty tones that give the dubbel its wide gamut of flavor complexity. Because of the special strains of ale yeast used in their production, dubbels often carry a mild spice.