Sheep casing is a natural sausage casing made from the small intestine of sheep, specifically the submucosa layer that remains after the other intestinal layers are stripped away during processing. It is the thinnest-walled natural casing available, which gives sausages a tender bite and a distinctive “snap” without any rubbery chewiness. If you’ve ever eaten a high-quality hot dog, a chipolata, or merguez, you’ve almost certainly eaten sheep casing.
How Sheep Casings Are Made
A sheep’s small intestine has four layers: the inner lining, the submucosa, a muscular layer, and an outer coating. During processing, all layers except the submucosa are scraped and cleaned away. This single remaining layer is what becomes the casing. It’s remarkably thin yet strong enough to hold ground meat during stuffing, cooking, and smoking.
After the cleaning and scraping steps, casings are sorted by diameter, graded for quality (typically A, AB, or BC grades based on consistency and integrity), and then packed in salt or brine for preservation. They arrive to butchers and home sausage makers as bundled lengths ready to be soaked and used.
What Makes Them Different From Hog Casings
The two most common natural casings are sheep and hog, and they serve different purposes. Sheep casings have a smaller diameter and a noticeably thinner wall. A sausage made with sheep casing will be slimmer and have a more delicate texture, while hog casings produce the fatter, chunkier sausages most people picture when they think of bratwurst or Italian links.
That thin wall is both an advantage and a trade-off. Sheep casings are semi-permeable, meaning they let smoke and cooking flavors pass through to the meat while keeping juices sealed inside. This is why they’re considered the gold standard for smoked sausages and frankfurters. However, the thinness also makes them more delicate and prone to tearing during stuffing. If you’re making sausage for the first time, hog casings are more forgiving to work with.
Standard Sizes and What They’re Used For
Sheep casings are measured by their inflated diameter in millimeters. The size you choose determines the type of sausage you can make:
- 18/20mm: The smallest standard size, used for merguez, cocktail sausages, and small Asian specialty sausages.
- 20/22mm: Common for breakfast links and snack sticks, especially in high-volume production.
- 22/24mm: One of the most widely used sizes, ideal for hot dogs, smoked wieners, and pork links.
- 24/26mm: A popular choice for lap cheong (Chinese dried sausage) and dried beef sausages.
- 26/28mm: The largest common sheep casing size, suited for oversized breakfast links, frankfurters, and sauerkraut sausages.
The numbers refer to the range after soaking. A casing labeled 22/24mm will expand to somewhere between 22 and 24 millimeters in diameter once rehydrated.
Tenderness Varies by Origin
Not all sheep casings feel the same in your mouth. Research comparing casings from different countries found meaningful differences in toughness. New Zealand lamb and Australian sheep casings tend to be the most tender, while Chinese sheep casings are noticeably tougher. Egyptian casings fall somewhere in the middle. The age of the animal also matters: casings from older sheep are significantly tougher than those from younger lambs, because the submucosa thickens and strengthens over time.
For sausages where a delicate, barely-there bite is important (like breakfast links or chipolatas), younger lamb casings from New Zealand or Australia are preferred. For sausages that need to hold up to drying or heavy smoking, a slightly tougher casing can be an asset.
Classic Sausages Made With Sheep Casing
Sheep casings are traditional for any sausage that benefits from a slim profile and tender texture. Chipolatas, the thin French pork sausages, are a classic example. Merguez, the spiced North African lamb sausage, is almost always in sheep casing. Frankfurters and Vienna-style sausages rely on sheep casing for their characteristic snap. Cocktail sausages, small fresh sausages, and many regional Asian sausages also use them.
How to Prepare and Store Them
Sheep casings are sold packed in salt, which preserves them but needs to be thoroughly rinsed off before use. Soak the casings in fresh, cool water for about 30 minutes to rehydrate them, then flush water through the inside of each length to open them up and check for holes. They’ll feel slippery and pliable when ready to slide onto a stuffing tube.
For storage, salted sheep casings keep well in the refrigerator for one to two years as long as they stay packed in salt and sealed from air. Many sausage makers report using casings stored for over a year with no change in smell or performance. You can also freeze them, though repeatedly freezing and thawing can weaken the casing walls. The simplest approach is to repack unused portions in salt after opening, store them in the fridge, and pull out what you need for each batch.