Q. I have been looking all over Charlotte for beef and pork middles, and I haven't had any luck. Do you know of a reliable source for these larger casings?
Natural sausage casings are a wonderful thing, strong but light, porous and yet somehow not. Your standard natural sausage casing is a hog casing. It's cut from the small intestine and has a diameter between 11/8 inch and 13/4 inch.
However, sausages of different diameters require different casings. You wouldn't want to put a skinny hot dog and a fat mortadella in the same size casing – not only would it fly in the face of tradition, but it would throw off the curing and cooking times.
For smaller sausages, hot dogs and such, look for sheep casings. For medium-diameter sausages, you have to track down middles. Bungs, the very largest casings, are used for large-diameter sausages. You can even use bladders, which are traditional for curing mortadella.
These larger casings are from lower in the digestive system, and though they are thoroughly flushed by the slaughterhouse, they can give off a strong odor at room temperature. This is inevitable and is perfectly natural.
Typically, the larger casings are inedible. They're not dangerous, but they are too thick and tough to eat. That's why you should peel sausages stuffed into larger casings before eating them.
Packed in salt and refrigerated, sausage casings last almost indefinitely. You can buy the regular size hog casings from the meat department at Reid's Fine Foods in Seventh Street Station.
I've also had good luck ordering sausage casings from The Sausage Maker Inc., an Internet-based business. They carry every kind I've ever needed. Find them online at www.sausagemaker.com.