Maryland-Style Crab Feast

steps

1. Have ready a large steamer pot or stockpot with steamer basket insert. (Alternatively, cook the crab in batches in a smaller pot.) If there is no steamer insert, improvise by coiling twisted ropes of aluminum foil in the bottom of the pot to hold the crabs above the liquid.
2. Pour beer (or a combo of beer and water) into the pot to reach a depth of about 1 inch. Add a few glugs of vinegar. Liquid must stay below steamer to ensure crabs cannot sink down into it, which can flood them and turn the meat mushy. Bring to a boil over medium-high heat. There should be plenty of steam rising through the steamer, but liquid should not bubble up through it.
3. Discard any dead crabs. They might be lethargic if deeply chilled, but they should move when prodded or jostled.
4. Using long tongs to protect your hands from the snappy crab claws, arrange a layer of crabs over the steamer rack, and sprinkle them generously with crab seasoning, depending on spice preference. Repeat to make no more than 4 layers of seasoned crab. Cook in batches, if necessary—it’s easy to overcook the crabs on the bottom of overfilled pots.  
5. Cover pot tightly and steam crabs until shells turn bright red with no remaining traces of blue, about 15 to 20 minutes, or perhaps longer if the pot is very large and/or very full. When cooking in batches, check liquid level between batches to ensure pot doesn’t boil dry.
6. Immediately pour the crabs onto a large table lined with paper, serve with melted butter, vinegar, and more seasoning, and have at ’em.