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.
This category includes processed casings—those not naturally occurring inside an animal. Non-edible 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.
Edible synthetic casings are made from collagen that’s usually derived from the inner layer of animal hides. While all collagen casings contain a small amount of cellulose for added heft, tougher inedible versions contain greater amounts. Collagen casings are more affordable than natural options and are typically used to make mass-market sausages, says Josh Graves, a trained butcher and the operations manager at Olympia Provisions, which manufactures various meat and charcuterie items in Portland, Oregon.
These are totally free of animal ingredients. Polysaccharide—a material similar to cellulose that’s made of glycerin, starch, a seaweed derivative called carrageenan, and water—is a popular choice. You’ll also see alginate, a gel made from seaweed that extruded filling passes through, enveloping the sausage, says Graves, the choice of Beyond Meat and Impossible Foods. Other vegan sausages, McNeil says, might be cooked in a synthetic casing but sold skinless.
Are there any kosher or halal sausage casings?
Halal and kosher casings exist across categories, and are prepared according to both sets of dietary rules. “So, no pork,” says McNeil. Graves says natural kosher and halal casings are more likely to be made with beef or sheep intestines, and synthetic options can be used so long as they’re produced appropriately. To ensure the sausage casings are kosher or halal, look for products that are certified with the requisite labels. You can find plenty of kosher brands here, and halal options include those made by Nema, Boxed Halal, Deen Halal, and more.
Can you taste a difference between the various casing types?
“I usually find that any casing flavor is too mild to be noticed over the flavor of the sausage,” Loew-Banayan says. You probably will notice a textural difference, though. “I think natural casings are the best in terms of getting the unique snap you want in a really good sausage,” says Graves. And if you’ve grilled a skinless veggie sausage before, you’ll know it’s harder to achieve those char lines and keep it from sticking to the grates.
How can you figure out which type of casing was used?
According to USDA requirements, both natural and collagen casings only need to be declared on product labels if the source of the casing is different from the meat used to make the sausage (for example, pig intestine encasing a chicken sausage, or beef collagen wrapping a pork sausage). So if the ingredient list on your pack of brats includes “Pork, pork fat, water,” and various seasonings, you can assume a natural pork or pork collagen casing is being used. Sausages sold in nonedible casings need to display a prominent statement—such as, “Remove casing before eating”—near the product name.
Now that you know how the sausage is made, make the sausage.