By putting meat in cold water and allowing water to heat gradually, a large amount of juice is extracted and meat is tasteless; and by long cooking the connective tissues are softened and dissolved, which gives to the stock when cold a jelly-like consistency. This principle applies to soup-making. By putting meat in boiling water, allowing the water to boil for a few minutes, then lowering the temperature, juices in the outer surface are quickly coagulated, and the inner juices are prevented from escaping. This principle applies where nutriment and flavor is desired in meat. Examples: Boiled mutton, fowl.
By putting in cold water, bringing quickly to the boiling point, then lowering the temperature and cooking slowly until meat is tender, some of the goodness will be in the stock, but a large portion left in the meat. Examples: Fowl, when cooked to use for made-over dishes, Scotch Broth.