Sausage casing

Sausage casing, also known as sausage skin or simply casing, is the material that encloses the filling of a sausage. Natural casings are made from animal intestines or skin; artificial casings, introduced in the early 20th century, are made of collagen and cellulose. The material is then shaped via a continuous extrusion process – producing a single sausage casing of indefinite length – which is then cut into desired lengths, usually while the extrusion process continues.