All “monastic” beers are not alike. Here’s a brief guide.
“Trappist” is not a kind of beer. Neither are “abbey beers.” But both abbey and Trappist beers do belong to the same unique craft tradition, and the methods used to brew one or the other are not that different. Two key things distinguish one from the other, though: 1) where the beer is made and 2) who brews it, as the master brewer David Jaimes Messori points out in this blog.
There are around 176 Trappist monasteries around the world; that is, monasteries that belong to the Order of the Cistercians of the Strict Observance, a branch of the Cistercian Order, which is in turn a branch of the Benedictine Order. Only eleven of those monasteries have the license, granted by the International Trappist Association, to brew beer. A small hexagon printed on the label of the bottle certifies the beer has been brewed by monks, strictly following the monastic rules of beer brewing, and that the revenues will be invested in the monastery, the community surrounding it, and the charities associated with the Trappist Order.