This changes the beef in two ways-first through desiccation, where moisture evaporates from the muscles, which helps to concentrate the beef's flavor. The second way occurs as the beef's natural enzymes break down the connective tissues in the muscle, making the meat extra tender.

"We take at last 28 days to make the dry-aged beef, and the duration depends on the size and the fat content of each piece of meat," says Yip.

"If the beef has more marbled veins, it needs more time to dry.

"Each piece will be labeled with the date it was put in and again when the process is complete. There will be a 'crust' on the surface, which will be trimmed off before cooking."

During the aging process, there is a significant loss of weight in the beef, which is one reason why this time-consuming dish is such a rarity in Beijing steakhouses.

"The beef has to be fresh to survive the dry-age process, and also it has to be of very high quality since the process requires meat with a large, evenly distributed fat content," says Yip.