Which of the following is NOT one of the ten Trappist breweries?

The answer is correct because Duvel is not one of the ten authentic Trappist breweries. The Trappist breweries are defined by their adherence to specific criteria, including being operated by monks living in a Trappist community. They also follow strict guidelines regarding the brewing process and the profits from sales are typically used to support the monastery and its community.

Chimay, Orval, and Rochefort, on the other hand, are all recognized Trappist breweries. Chimay is known for its strong ales, Orval is notable for its unique yeast and dry-hopping techniques, and Rochefort is famous for its rich, complex dark ales. Each of these breweries maintains an experimental and traditional brewing philosophy aligned with Trappist values, making them legitimate members of the Trappist brewing community. In contrast, Duvel is produced by Brouwerij Duvel Moortgat, which, while renowned for its Belgian-style ales, operates as a commercial brewery and does not meet the criteria to be designated as a Trappist brewery.