Put the pork loin into a large pot and add 8 cups of cold water. Bring to a boil, skimming off and discarding any foam that rises to the top. Add the salt, bay leaf, garlic, and parsley root. Reduce the heat to medium-low and cook, uncovered, for 1½ hours or until the pork is very tender.
Remove the meat from the pot and set aside. Strain the stock, discarding the solids, and return it