After a beef animal is slaughtered it is hung in a cooler to reduce its temperature, and control the process of aging.
Most of the beef in America is flash aged in a vacuum-sealed bags , this is typically the meat you find in your grocery stores.
Smaller custom USDA slaughterhouses that work with local farms will usually dry age a carcase for 10-14 days. Many of these smaller facilities don't have the room to hang meats for more than 14 days.
Many upscale butcher shops and restaurants believe beef needs to be aged for a minimum of 21 days to start to tenderize. These shops and restaurants may dry age or wet age, many from 21-42 days, and a very select few will age longer than 42 days
- Wet aging: In commercial and industrial slaughterhouses beef carcases are wet aged. The carcases are vacuum sealed in a bag to prevent moisture loss, this process takes 24-48 hours.
- Dry aging: There are a few different ways beef can be dry aged. Most smaller USDA slaughterhouses will dry age beef carcases for 10-14 days, a few will age to 28 days. Some upscale restaurants and butcher shops will bring in carcases and break them down into primal cuts, or sub-primal cuts and age them on a rack in a specially designed climate controlled cooler. These upscale restaurants and butcher shops will age for a minimum 21 days but usually 28-70 days some even longer. Dry aging beef for 45 days removes 12-25% of the moisture which intensifies the flavor. During the aging process connective tissues are broken down, which tenderizes the meat. Moisture loss, and trim loss can account for 30-50% loss of weight. You can expect to pay 50-200% more for a good dry aged steak.