The 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. The abbey had, since 10 December 1836, brewed a light coloured 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.he dubbel (also double) is a Belgian Trappist beer naming convention.