A brief history of Sausages, Casings, and an outline of the difference between Natural and Artificial Casings.
The History of Sausages.
Sausages are one of the oldest forms of prepared or processed foods in history. Animal intestines have been used for sausage making since around 4,000 BC. Although the history of sausages is difficult to trace, it is believed that the Sumerians (present-day Iraq) invented sausages and discovered the process.
There is also reference to a sausage recipe known in Babylon around 3,750 years ago in the world’s oldest cookbook as well as references to sausages in numerous texts. One of these texts includes a poem written by the Greek poet Homer in Odyssey (book 20, poem 25) where he mentions a blood sausage.
Numerous books report that sausages were popular among the Greeks and Romans. Lucanica is a short and fat sausage in Ancient Roman Cuisine. The following is a link to a Lucanian sausage recipe detailing the methods and ingredients to cooking the sausage: http://www.coquinaria.nl/english/recipes/12.4histrecipe.html
There are numerous ways of making sausages and there are also endless types of sausages, these include variations in the meat, whether the sausages are smoked, cured etc. One of these variations is the outer layer holding it all together, keeping in all the flavours and giving the sausage a nice texture. This is known as the Casing.
Casings can be split into two main categories, Natural and Artificial.
Animal small intestines consist of four layers. These layers are the:
a. Serose Membrane
b. Muscular Layer
c. Submucose Membrane
d. Mucose Membrane
Casings are made of the submucosa layer of the small intestine.
The cleaning process of sheep casings consists of various machines with each machine having its own purpose in the process. Some machines remove the inner layers while others remove the outer. You can see these layers in the following diagram:
Once all unwanted elements are removed and the casings are fully cleaned, they are then salted and ready for the selection process.
The selection process is immensely precise and is carried out by experienced professionals. These skilled workers check each casing and sort them into various grades and diameters.
The selected casings are then carefully measured by hand. We prefer to measure by hand rather than machine for the sake of accuracy and experience proves it to be more precise. The selected casings are measured into hanks of a specific length. The length of each hank is determined by the customers criteria. The next process is the salting and packaging stage.
The hanks are salted and packaged in nets, bags, etc. depending on the customers preferences. They can also be spooled. Spooling is carried out by a machine.
Artificial casings are used as an alternative to natural casings. There are many different types of artificial casings including Collagen, Cellulose, and Plastic casings.
Collagen casings are the closest variety of artificial casings to their natural counterpart. They are manufactured using collagen derived from beef or pig hides, bones, and tendons. Most are edible unlike Cellulose and Plastic casings, although they lack the bite of a natural sausage casing.
Cellulose is used to make tough casings. It usually comes from cotton liners and wood pulp. The casing is peeled off after cooking.
Plastic casings are generally made from Polyamide, Polypropylene or Polyethylene. They are used for cooked sausages, ham, and luncheon meat.