Trappist ale is a beer that is brewed only in Trappist monasteries, or under license of a Trappist monastery. Its appellation is thus based on origin rather than referring to a style. These beers are identified as “trappiste” and are made by only five breweries in Belgium and one in the Netherlands.
The five abbeys in Belgium are Orval, Chimay, Rochefort, Westvleteren, and Westmalle. There are commercial versions, not brewed under the control of monks, that are referred to as “bière d’abbaye” or “abbey beer.” The ingredients and brewing methods for abbey beers are similar to those for the Trappist beers. Although widely varying in character, Trappist beers are generally regarded as relatively strong, malty, and fruity, with a unique Belgian spiciness and a slight acidity that sets them apart from all other ale traditions.
Trappist ales are brewed primarily with two-row Pilsner or pale ale malts. Small amounts of Cara-Vienne, Cara-Munich, and Special B are added to impart raisiny and plummy flavors. Sugar in the form of “candi sugar” – which is 99% sucrose – is another important ingredient. Trappists are generously hopped, which serves to emphasize aroma more than bitterness.
Trappists are fermented at temperatures ranging from 18 to 28ºC to increase the production of esters. Maturation can last between 5 and 7 weeks at temperatures ranging from 7 to 16ºC. Some brewers prefer dry-hopping trappist ales at the start of maturation. After maturation, the beer is rough-filtered or centrifuged, primed, re-yeasted, and bottled. Trappist ales are all bottle-conditioned up to 3 months.