The Belgian “Dubbel” was actually just a description used for commercial purposes by Trappist breweries in Belgium. Once upon a time a dubbel or double from different breweries could vary from blonde to brown and have a wide array of bitterness and alcohol. Over time it seemed to be known that a dubbel would refer to a stronger amber to brown ale with a mild bitterness and a focus on caramel malts or candi rock sugar brewed with a Belgian Ale yeast strain.