Carcasses or meat are aged by holding them at refrigeration temperatures for extended periods of time after slaughter and initial chill. Aging (or conditioning as it is called in many countries) improves the tenderness and flavor of meat. There are two methods for aging meat: wet aging and dry aging.
Dry aging is much more expensive and takes longer than wet aging. Meat which is dry aged is hung in a very clean, temperature and humidity controlled cooler for a period of two to four weeks. During this time, enzymes within the meat break down the muscle and connective tissue making it tender. Moisture is lost from the outer parts of the carcass causing an inedible crust to form which must be trimmed off and discarded. The carefully controlled environment, the time involved, and the loss of outer portions of the carcass make dry aging a costly process.
Wet aging occurs when meat and its own juices are vacuum packed in plastic and boxed for distribution. Because the plastic packaging does not allow loss of moisture, the meat may absorb more moisture which results in an increase in juiciness and tenderness. Both methods of aging work well and can create a better product. The difference is that dry aging gives a more distinctive flavor while wet aging is much less costly and allows for a quicker entry to the market and therefore a much longer shelf-life.
Due to the carefully controlled conditions required to safely age meat, aging meat at home is not recommended.