Dry aging is a preservation method of animal protein, normally associated with beef. It is the opposite of wet aging, a preservation method that is absolutely disgusting, but which is much more cost effective. In dry aging, the carcass is left to hang, unprotected, in a temperature controlled, sanitary environment for a period of time ranging from a few days to a few months. As a former employer told me, “The longer it sets, the better it gets.” I have found this to be the case. You can tell the difference between a steak cut from a rib aged a week and one that has been aged six weeks. The proteins break down by natural enzymes in the beef. Moisture is lost, creating a concentration of flavor. Think of salt water in terms of flavor. The longer the solution sits, the more you will taste the salt. This is exactly the same thing that happens with beef. The moisture leaves, the flavor is left behind.
Dry aged beef is, as a rule, more expensive. There is much greater loss, much less yield in salable product. The following are photos of different stages of dry aged beef:
Clearly the ends are inedible. This is part of the loss factor I described earlier. Depending on the length of the aging process, these ends can get pretty gnarly, and the undesirable sections will reach deep into the meat.