Short ribs and pot roast are close neighbors on the cow, but they couldn't be further apart in taste. Pot roast exudes the beefy flavor that only comes from muscles that got a lot of work. Short ribs, though, possess a rich, marbled flavor, similar to prime rib but with the added kick of bone marrow. Both cuts have their advantages, differences and similarities, but if you're looking for big flavor at a low cost, you won't feel disappointed with either.
Primal cuts, the major muscle groups, break down into smaller sub-primal cuts, which break down into roasts and steaks, or market cuts. Short ribs come from the lower rib and the upper plate primals, along with a small portion of the chuck primal. Pot-roast cuts, on the other hand, originate only from the chuck primal, which starts at the shoulder and extends down to the lower chest. The chuck, lower rib and upper plate have a lot of flavor, but not much tenderness, so expect it to take a few hours to cook short ribs and pot roast to tenderness.
Pot roasts come from almost every chuck sub-primal cut, but most often from the chuck 7-bone pot roast, shoulder pot roast, chuck pot roast and shoulder center sub-primals. The sub-primals give you the market cuts you see at the store: cross-rib roast, chuck eye, arm roast, shoulder roast, top-blade pot roast, under-blade pot roast, rump roast, eye round roast and bottom round roast. Short ribs always come from the lower part of the ribs on the side and underside of the beef carcass. Although several market cuts classify as pot roast, you cook them all the same as short ribs: with low temperature and moist heat.
You get best results from short ribs and pot roast when you sear them in hot fat, then braise them until tender. Sear the seasoned pot roast or short ribs in a few tablespoons of oil or butter in a Dutch oven over medium-high heat until golden brown all over. Remove the meat and saute aromatic vegetables, such as roughly chopped onions, carrots and celery, until golden brown. Pour a few cups of cold stock or broth in the Dutch oven and scrape the bottom with a wooden spoon. Add the meat and enough stock or broth to reach halfway up the sides of the pot and braise in a 250 degree Fahrenheit oven until tender, or about three to six hours, depending on size.
Marinades are optional when preparing pot roast and short ribs, since the low, moist heat takes care of tenderization. Pot roasts make better use of acidic marinades than short ribs, though, because pot roasts' toughness comes mainly from exercise and short rib's toughness comes from connective tissue, which only breaks down during cooking. You can still marinate short ribs for flavor, though. Marinate the pot roast or short ribs for 30 minutes per pound using a base consisting of 1 cup oil to 1 tablespoon acid, such as lemon juice or Worcestershire sauce, and add spices and herbs as you prefer.