Sausage casing refers to a variety of different products into which ground meats, spices, and vegetables can be stuffed in order to produce a firmly packed product. Some sausages go into casings to then be smoked or pre-cooked, while others are packed into fresh edible casings and are sold fresh. Shoppers can also find some sausages that are not made in casings, but are molded together instead, but these are less common.
Casings can come in several varieties. Some forms are not edible, like the fibrous sausage casing, and these tend to be made of cellulose and often resemble paper. They may be treated with wax to seal in the flavors of certain sausages. Consumers are likely to see the fibrous casings on products like salami or summer sausage. These casing types have the disadvantage of needing to be peeled off prior to eating the sausage.
There are two types of sausage casing that are made from collagen. One form is chemically produced to form uniform sizes so that cooks can always make sausages in predictable sizes. Some sausage experts prefer what is referred to as the natural casings. This is also collagen, but is usually made from intestine of pig, lamb, or cow, that has been cleaned and stripped of fat. Since intestinal size can vary, sausages forced into natural casings may vary a bit in size. Shoppers who are looking for strictly kosher sausages will want to check that any beef sausages do not make use of pork casings.
When not on the sausage, both collagen and natural sausage casing resemble a semi-clear sheath. They are usually placed onto a sausage maker, which forces the meat and other ingredients into the casing. Both types are completely edible, but may pop when exposed to high heat. They also add crunch to the sausage if they are overcooked a bit.
To date, there are few vegetarian sausages that come in an edible casing. Some are available with a little snap, but other sausages may get a crumb coating so they’ll be similar to a regular casing in crunch. Others merely place sausage in a plastic casing, from which cooks can make sausage patties, always a good alternative. People who feel a little leery about eating animal intestines in general will find that most sausage patties do not feature any type of casing and may be preferred.