Ever wondered what exactly sausage casings are made from? We have all the spicy details you crave.
In the United States alone, there are more than 200 varieties of sausage: from spicy Cajun andouille and peppery Mexican chorizo to smoky Polish kielbasa, garlicky Italian sausage, and gingery German bratwursts.
And yet, as different as these sausage varieties are, they all have one thing in common. They are all made using the same process. You chop fatty meat, run it through a grinder, season it with salt and spices, stuff it into casings, and tie the newly-formed sausages into links.
You’re here, which means you want to learn more about one particular step in this process—and that’s the casings used to make the sausage. What, oh what, are sausage casings made of?
The answer depends on the kind of sausage. Usually, you will encounter three types of sausage casings: edible casings made of natural material, edible casings made of artificial material, and inedible casings made of plastic.
In a moment, we will go through everything you might have wondered about when it comes to sausage casings, including what material they’re made of and how they’re made.
Natural Sausage Casings
Natural casings have been used to make sausages for around 6,000 years. And, despite the invention of artificial sausage casings, they are still around.
Natural sausage casings, as you can probably guess, are made from animal intestines; specifically, the sub-mucosa, one of the layers of tissue within the small intestine.
Pig intestines are what is most commonly used for sausage casings, particularly in North America, Western Europe, and China. That said, other animals are also used in other parts of the world: sausage casings can come from cows, sheep, goats, and even horses.
You can often tell the difference between natural and artificial sausage casings by their appearance. Artificial casings tend to be more uniform in their appearance, while natural casings are somewhat irregular in size and shape. This is due to the fact that natural casings come straight from animals and aren’t heavily processed.
Natural sausage casings are made by taking an animal’s small intestine and scraping off everything except the sub-mucosa. The casings are then salted to lower their moisture content, which helps preserve them and prevents microbes from growing on them.
Aside from the fact that natural sausage casings are processed by machines rather than by hand, the actual process of making natural sausage casings has remained basically the same since it was invented.
Natural sausage casings are considered by many to be “the best” kind of casing. They are expensive—and take longer to make than other types of casings—they say natural casings impart a deeper flavor on the sausage during cooking because they “breathe” more easily than their artificial counterparts.
Artificial Sausage Casings
Judging by the name, you’d think that artificial sausage casings are made out of plastic. But you’d be wrong.
These misleadingly-named casings are usually made from animal products although, unlike natural casings, they don’t use whole animal parts.
Artificial casings are usually made from collagen—a kind of protein derived from animal skins, bones, and tendons. Cow and pig skins are most often used to make artificial sausage casings.
Aside from cows and pigs, artificial sausage casings are sometimes made from collagen derived from poultry and fish. Artificial sausage casings may not be as visually appealing as natural sausage casings, but they are both quicker and cheaper to make than natural casings.
In addition, artificial sausage casings can sometimes be made from cellulose, the stuff that makes up the walls of plant cells, which is derived from plant fiber. In recent years, in fact, more and more manufacturers have begun producing artificial sausage casings entirely made from plant-based materials.
Compared to natural sausage casings, artificial casings are practically a brand-new invention, having only been around for the past 50 years or so. Despite this, their popularity has been steadily increasing since they were invented.
Artificial casings have a few advantages and disadvantages compared to natural casings. When using artificial casings, it’s a lot easier to make multiple sausages of equal weight and size, because you can extrude artificial casings to be whatever length and diameter you want.
On the other hand, artificial casings are more tender than natural casings when cooked, but don’t have the same “snap” when you bite into them that natural casings do. For those people who care as much about texture as they do about taste in terms of their food, this might be a bit of a dealbreaker.
It’s also worth noting that not all artificial sausage casings are actually edible. Some casings, for example, the ones you’ll sometimes find on certain salami varieties, are applied too thickly to the sausage to actually be edible and need to be peeled off before the sausage can be eaten. Many cellulose-based casings are also totally inedible.
Finally, we have plastic casings, which are always inedible. Specifically, these casings are made of polymers like polyethylene, polypropylene, and polyamide. Many sausage casings made from cellulose also fall into the general category of inedible casings.
Since smoke and water can’t get through plastic casings, these casings are usually used with sausages that aren’t intended to be smoked or that need to retain most of their moisture content. For example, sausages like bologna or hot dogs are often cooked in a plastic casing. With these types of sausages, the casing is usually removed before the sausage is sold.
Even though plastic sausage casings aren’t edible as such, don’t worry if you accidentally eat a slice of kielbasa or something that still has the plastic on it. While you’re not supposed to eat plastic sausage casings, they’re totally non-toxic and will simply pass through you.
Using plastic sausage casings can have a few advantages. Some plastic casings are designed to shrink during cooking, which helps retain more moisture within the meat. Other types of plastic casings retain the moisture content of the meat but allow it to expand during cooking.
How Are Sausage Casings Made?
Regardless of what kind of sausage casing you’re talking about, basically, all of them are made through the process of extrusion.
If you’re not familiar, extrusion involves taking the material used to make sausage casings and forcing it through a hole of a certain diameter.
Usually, the casings are extruded as one single long casing and are then cut into smaller casings as needed.