Some tips on braising from
Harold McGee:
• No matter what you're braising - big roast, small chunks of meat, or a vegetable - use a heavy pot that conducts heat well, with a tight-fitting lid.
• Keep meat chunks large, and try not to give them ragged edges or pierce them when you put them into the pot. You want their juices to stay in and also be able to absorb and retain the moisture you're adding.
• If you're cooking meat, brown it very quickly over high heat. You don't want to cook the meat very much at all - just create flavor.
• Manage the heat; just boiling meat for two hours will not make a tender stew.
• Start the braise in a cold oven or over a cold burner, and let the the liquid slowly heat over a period of two hours. McGee says that the time that the meat spends below 120F replicates the aging process, weakening connective tissue, so a slow, deliberate warming will make it even more tender.
• Let the meat or vegetable cool in the liquid. This will help it reabsorb moisture.