How can you tell when a pot roast is done? What internal temperature am I looking for? I cooked a rump roast for 3 1/2 hours, and it was very dry. - Tim Ryan, Holbrook
A thermometer is invaluable for true roasting: Take beef or lamb out of the oven when the temperature reaches 120 for rare, 125 to 130 for medium-rare, 135 to 140 for medium, 145 to 150 for well. But internal temperature is not a good guide to doneness when you are pot roasting, i.e. braising.
Braising (or pot roasting) means cooking meat slowly in a lidded pot where the meat is partially covered by liquid. Meat cooked this way may achieve internal temperatures of more than 200 degrees, but that will not tell you if the meat has achieved peak tenderness because braised tenderness is not just a function of tem-perature. Tenderness is what happens when all the meat's fat has melted and its connective tissue has dis-solved. That connective tissue, so unpleasant when encountered in a steak, is made from collagen. Slow, moist heat turns it into gelatin, which lends a silky smoothness to the finished dish.
I submit that your pot roast was dry because it was made from a rump roast. The rump, from the rear end of the steer, lacks both the fat and the connective tissue of a great braising cut. My favorite cut to braise is a chuck roast, which is blessed with both.
Note to brisket braisers: This cut also can tend toward dryness. Try to get a brisket with a nice fat cap on it and make sure the fat is facing upward in the oven.
Here is a standard braising procedure: In a pan just large enough to hold the roast snugly, brown the meat all over in a little oil, then remove it from the pan. Add more oil to pan and saute a lot of chopped onions, celery, carrots, salt and pepper until soft. If desired, add some herbs and/or garlic, then nestle in the meat, fat-side up, and add enough liquid (broth, water, wine, beer or a combination) to come about halfway up the roast. Bring to a simmer, then cook at a very slow simmer either on top of the stove or, easier still, in a 300-degree oven. Turn roast over once or twice an hour and add more liquid, if necessary. Depending on the size of the roast, the meat will be done in anywhere from 3 to 5 hours. Pierce it with a sharp knife, and it should offer almost no resistance. Let the meat rest, covered, in its cooking liquid for at least 45 minutes and up to 2 hours. To thicken braising liquid, pour it into a saucepan and reduce it.