In a small bowl, mix the wine, garlic, bay leaves and allspice. Marinate the butt, skin and fat for 30-45 minutes. Cut the pork skin in strips about ½” x 7” and feed it through a meat grinder fitted with 1/8” openings. Cut the fats into pieces and grind at a 3/16” setting. Cut the lean butt in pieces and grind at 1/2” or have the butcher do the grinding.

In a large bowl, mix the ground meats with your hands (or use a mixer dough hook), adding the salt, ground pepper, whole peppercorns, and the saltpeter, if desired, and distributing them evenly. Strain the wine marinade over the meat and mix thoroughly. Cover and refrigerate overnight.

Wash the sausage casing well, pat dry, and stuff with meat mixture, tying off sausages every 6” or 7” and leaving 1” unfilled casing between them. Continue until all the meat has been used.  Hang the cotechino overnight in a cold place (50-55 degrees), exposing all sides to the air, then refrigerate until ready to use.

To cook, set the cotechino in lightly salted cold water with 6 bay leaves. Bring to a boil, reduce to a simmer, and cook 1 hour. Remove and drain the cotechino, slice it 1/2” thick, and, after removing the casing, serve with good mustard and mostarda di Cremona (available at Italian groceries and specialty food shops). The best accompaniment for cotechino is lentils.