What Are Sausage Casings Made Of?

In Too Afraid to Ask, we’re answering food-related questions that may or may not give you goosebumps. Today: What in the world is sausage casing made of?

“How the sausage is made” historically had nothing to do with sausage and everything to do with arts, politics, and—of course—secrets. But today we will dare to learn about how the literal sausage is made. The frank, the link, the banger, the wiener, the weenie, the snag…whatever you want to call it.

Most sausages are made by forcing chopped or ground meat, fat, and seasonings into a skin of sorts (called the casing), which then gets tied or twisted to create individual links. These days we also see category-breaking breakfast sausage patties and loose sausages (essentially, spiced ground meat) on the market that don’t require a casing. But traditionally—as in, thousands of years ago—virtually all sausages were encased inside the intestinal tracts of various animals.

Outliers aside, the vast majority of sausages need “some sort of container to hold their shape until they’re cooked,” says Shaina Loew-Banayan, the chef-owner of Cafe Mutton in Hudson, New York, one of our Best New Restaurants of 2022, which serves a range of house-made links. Technically, anything that fulfills this purpose could be considered a casing. “In my experience, cooking some sausage meat inside a latex glove makes for a perfect prank; there is nothing more unsettling than finding a meat hand in the fridge,” says Loew-Banayan. The commercial sausages you buy at the store or butcher, however, are made with a slew of natural, manmade, and plant-based options.

Here’s everything you ever wanted to know (and maybe some of what you didn’t) about sausage casings.

What is sausage casing made of?

Originally, sausage meat was only ever enveloped by various animal organs. Called natural casings, these by-products are still popular today. You’ll also see various synthetic sausage casings on the market, including vegan options sometimes used for plant-based sausages, and others which are either edible (collagen) or inedible (plastic or paper wrap intended to be removed before cooking or eating). Here are the three main types and where you might expect to find them.

Natural casings

These are derived from the intestines of animals. Primarily made of pig, cow, goat, and sheep intestines, they’ve been used for centuries. Texts written 4,000 years ago by ancient Sumerians of Mesopotamia documented meat stuffed into intestinal casings; technically, it’s the submucosa, a collagen layer that makes the intestinal organ strong and flexible. (In most cases, the fatty outer layers of muscle are removed from the organ, along with the inner layer of mucous membrane—leaving only the stretchy stuff behind.) Usually at the slaughterhouse, the isolated submucosa is salted to dry and preserve the casing.

Today, plenty of butchers still prefer a natural casing for sausage making, and you’ll see a variety of organs used: There’s haggis, which is offal stuffed in a sheep’s stomach. Some large format sausages might be contained by a cow’s appendix (known in the industry as, unfortunately, the bung). And at Cafe Mutton, Loew-Banayan opts for a smaller sheep intestine when making “skinny guys like hot dogs.” But virtually any type of sausage designed to be cooked and eaten in the skin could be made with a natural casing.

Synthetic casings

This category includes processed casings—those not naturally occurring inside an animal. Nonedible synthetic casings might be made from cellulose, a wood- or cotton-derived ingredient that’s often used for sausages which are smoked or steam-cooked, because it’s more permeable than other varieties, says food scientist Topher McNeil, PhD. Pepperoni, bologna, and liverwurst are likely cooked in cellulose, which needs to be removed before eating. And plastic casings are frequently used to cook sausages that are customarily sold pre-peeled—most hot dogs and deli meats like mortadella.