Sausage is made from combining various types of ground meat with different combinations of spices and salt. A very necessary component of sausage is the outside hog casing. The casing is the packaging used to hold the combined ingredients together and is made from an animal product.

Typically, and traditionally, hog casings are made from the intestine of the hog. These casings contain the ground sausage meat. Some casings are made synthetically.

Natural hog casings are removed during the butchering process. The intestine is cleaned by squeezing and scraping to remove undesirable particles. The casing is then rinsed thoroughly. The casings can be stored by packing them in salt.

Individual and link sausages are made by pressing the ground meat mixture into a length of hog casing. The casing is then cut and tied off at intervals to form individual sausages.

Natural hog casings are edible and are normally consumed with the sausage. Some people prefer to peel away the casing after the sausage is cooked, rather than eating it.

Synthetic casings are made from collagen, although some companies are beginning to produce non-collagen synthetic casings. Synthetic casings come in both edible and inedible forms.

Edible synthetic casings are used in individual sausages and sausage links. Inedible casing is used around soft lunch meats, such as bologna. This should always be removed before consuming the meat.