We think most of your cookbooks do discuss the problem, because it has everything to do with time and temperature. And you have too much of one or the other or both. It sounds like you’re seriously overcooking the meats.
When you overcook meat, the fibrous proteins in it become solid, dense, and dry. You need to find a happy compromise between getting the meat done and keeping it moist and tender.
We strongly suggest you invest in an instant-read thermometer, which will help you know when your meat is fully cooked. Meats will continue to cook after you remove them from the heat - small cuts like pork chops and hamburgers will rise an additional 5° or so while large roasts will rise 10° or so - so you should remove them shortly before they reach the desired temperature.
The US Department of Agriculture says the following temperatures will produce safely cooked, but still flavorful meats:Meat Internal Temp. Centigrade Fresh ground beef, veal, lamb, pork 160°F 71°C Beef, veal, lamb roasts, steaks, chops: medium rare 145°F 63°C Beef, veal, lamb roasts, steaks, chops: medium 160°F 71°C Beef, veal, lamb roasts, steaks, chops: well done 170°F 77°C Fresh pork roasts, steaks, chops: medium 160°F 71°C Fresh pork roasts, steaks, chops: well done 170°F 77°C Ham: cooked before eating 160°F 71°C Ham: fully cooked, to reheat 140°F 60°C Ground chicken/turkey 165° F 74°C Whole chicken/turkey 180° F 82°C Poultry breasts, roasts 170° F 77°C
Additionally, the USDA says the thighs and wings of poultry should be cooked "until the juices run clear."
Some people say the government, with all its lawyers and bureaucrats, errs on the side of caution at the expense of flavor, and that some meats taste much better cooked 5° to 10° lower. You will notice that there is no allowance in the chart above for meats cooked rare, for instance. Similarly, when the thigh of a roast chicken reaches 180°, the breast is still around 165° to 170°, which is, in the opinion of many, a little overcooked for best flavor. If you cook the bird until the breast is 180°, the thigh will be around 190° and no part of the bird will be particularly appetizing.