Late 19th century food scientists examined meat doneness, offering temperature/time recommendations according to type of meat, cut, and method of cooking. Meat thermometers (1930s) took the guesswork out of judging doneness. When today we ask for our steak well done, medium or rare, we are repeating a choice that the Renaissance writers revived from Hippocratic writings.Like their 17th century predecessors, early 20th cooking texts warn against rare meat. Black and blue (aka "Pittsburgh style" steak surfaces in print in the 1970s. In 1626 Pierre Duchatel noted the physical reactions to be expected from meat prepared in each of the thre ways '(1)...well-Boiled meat is suitable to the digestion. (2)...those meats that have been medium boiled or medium roasted add moderately to vigor and digestion.
Fat coats and lubricates meat fibers during cooking, and stimulates the flow of saliva and creates the sensation of juiciness no matter hwo dry the meat fibers themselves have become.
Medieval physicists--or physicians--told their contemporaries that cooking added either warmth and moisture or warmth and dryness to their foodstuff that was cooked: the cook chose his cooking method according to the inherent nature of the foodstuff and any need he had to correct this nature.