Stews are a perfect way to use the tougher, cheaper cuts of meat. Long, slow cooking makes the meat tender and full of flavor. But tough, stringy meat can be the result of cover cooking, especially if it is cooked at too high a temperature so that the liquid boils and breaks up the fibers of the meat. The temperature at which the stew cooks should be no higher than 50C, and this should be maintained for at least 2 hours. The aim is to achieve a very gently simmering, with only the occasional bubble breaking the surface of the liquid. A heat diffuser made of wire mesh and placed between the hot-plate and saucepan can prevent the stew cooking too quickly.
The pan should be heavy with a tight-fitting lid that keeps in the moisture. A pan that is too thin or buckled can cause the stew to burn at the bottom. Your pan should also be the appropriate size; small quantities of stew in a large pan will dry out very quickly, while too much food in a small pan might boil over.
** Asian Recipes