Natural casing:The best choice for sausage
                        makers!
                 
                As one of the biggest country in the world,China play a leading
                    role in the production of natural casing products.In 2004,China
                    exported over 500 million USD natural casings worldwide.
                Natural casings:
                
                  - are a natural product; 
- are edible and easy to digest; 
- respond in the same way as meat to drying, smoking and
                    cooking; 
- are porous; 
- absorb enough moisture; 
- absorb smoke flavours; 
- adopt attractive colours when smoked; 
- are flexible; 
- are environmentally friendly; 
- have an attractive home-style appearance. 
Natural casings dimensions
      The diameter of natural casings is expressed in terms of calibre. 
      The calibre shows the number of mm of the diameter when the casing is stuffed. 
      Example: 20/22 calibre means between 20 and 22 mm. 
      The colour of the binding ring often indicates the calibre.
                 
                Quality issues
      Sheep casings are assessed mainly in terms of the presence of holes.
      A-quality casings are free of holes.
      B-quality casings have few holes, of medium size (3 mm in diameter).
      The casings are filled with water or air to determine the quality.
      At the same time the diameter is calibrated.
      Casings are classified in stages of 2 and 3 mm.
      Hog casings from 26 mm to 45 mm or more.
      Sheep casings from 14 mm to 28 mm or more.
      Sometimes, the casings exceed the maximum diameter. They are then categorised
      as 'extra wide'.
                Fringe on the casing ('whiskers')
                    Casings may have a small fringe of connective tissue. These
                    are the remains of blood vessels in the caul, and show that the
                    caul was not cut away cleanly from the small intestine. Heating
                    removes these 'whiskers'.
                    
                    Visible fat around veins (veiny tissue)
                    The veins are the remains of blood vessels. The fat around the veins
        is clearly visible. This fat disappears when the casings are heated.
        
        Light (thin) spots in the intestinal wall (worm holes)
        The light spots arise during cleaning. The show the sites of lymph glands,
        the 'Peyer plates'. These plates are removed, together wit the mucous membrane.
        As a result, the tissue is thinner at these points.
        
        Supply units for natural casings
        Supplied in hanks or bundles
      Lengths vary. 
      Lengths are measured by machine or manually, when the casings are wet.
                 
                Packing of natural casings
                In dry salt or brine pack in barrels
                Pre-flushed pack in barrels 
                Soft or hard tubed pack in barrels
                 
                Storage of natural casings
                    Casings should be stored in a controlled, cool environment.
                    Special care should be taken to avoid excessive heat. A neutral
                    temperature of 4-10ˇăC is ideal.
                (source from HBS and CNSCA)