Natural Casing
Also known as Casing
The cleaned intestine or bladder of an animal, used to hold a sausage's shape while it ferments and dries. Its width sets the drying rate and the section of the finished salume.
A natural casing is the cleaned submucosa of an animal's intestine, and it is chosen over a manufactured one for a physical property rather than tradition alone: it breathes. Water vapour passes out through it and smoke passes in, so a sausage in a natural casing dries as a whole rather than sweating inside a bag, and it shrinks with the meat as it goes. That last point matters more than it sounds. A drying sausage loses a third or more of its volume, and a casing that cannot follow it inward leaves voids and wrinkles where a clinging one gives a smooth, dense finished piece.
The width sets the calendar. Sheep casings, around 20 to 26 mm, dry in weeks; hog casings, roughly 32 to 42 mm, take longer; beef middles and bungs, from 50 mm up past 100, take months. Because drying time grows with roughly the square of the thickness, moving a recipe from a hog casing to a beef middle does not add a few days, it changes the product into a different one with a different season. The width also decides the slice, which is why the same farce cased narrow and cased wide gives two salumi with different names in most traditions.
Casings arrive packed in salt and must be treated as the raw animal material they are. They are rinsed, then soaked in cool water to rehydrate and to flush the salt from the interior, and they are flushed through the lumen rather than merely soaked outside. Warm water is a mistake; it weakens them. A soaked casing should be slippery, supple and free of the salt smell.
They are inconsistent by nature, and this is the honest cost. Diameter varies along a single length, so pieces from one batch dry at slightly different rates. There will be weak spots that burst under pressure while stuffing, and the occasional hole. Stuff firmly but not tightly, keep the pressure even, and prick deliberately where air is trapped rather than reflexively along the whole length.
Fitness for purpose comes last and decides the choice. Cook a fresh sausage and any tender casing serves. Dry a salame for three months and it needs a casing that breathes, clings and holds a mould bloom, and that is the natural casing's territory.
Temple element. Roof, Microclimate