We had the good fortune to visit Rochefort a few years ago. The brewhouse really is a brewing cathedral. The tour (given by the brewmaster, Gumar Santos) ended in the tasting room. He served us 6, then he served us 8, then 10, and then, "Which did you like?", and more came around. Then, "How about some beer for the bus?" Plus everyone got a Rochefort chalice. Very nice.
Their fermentation process is rather unusual (at least to me). They brew Tuesday through Thursday, two batches each day, and one on Friday, all of the same beer. The first batch goes into the unitank around 11:00 AM on Tuesday, and the yeast is pitched. The second batch goes on top of that, followed by each successive batch through the week. After the last batch the fermenter is exactly half-full. (They did some experimentation, and found that the flavor was not the same if the tank was filled any higher.) The temperature is held at 24° C (76° F). That beer is bottled on Monday morning, so the last batch spends less than 72 hours in the fermenter. They never dump the trub, nor dump or skim the yeast. The bottling line is very state-of-the-art, and is massively oversized compared to most breweries. They want to be able to bottle an entire week's production in one work shift, because bottling is a very noisy process, and they're trying to minimize how long they disturb the monks. The bottles are conditioned from six to ten weeks, depending on the beer. The conditioning rooms are not heated or cooled. They look like oversized garages, and the temperature is controlled by opening or closing the doors.