Rinse the crabs with cool water and transfer to a large cooler. Top with ice and let sit until the crabs are still, about 1 hour.

Meanwhile, to make the seafood seasoning, grind the bay leaves in a spice grinder until finely ground. Transfer to a bowl and stir in the paprika, celery salt and cayenne.

Pour the beer into a 36-quart stockpot with a basket insert and add the vinegar, 2 tablespoons of the seafood seasoning and 6 cups water. Stir to combine. Add the steamer basket (the liquid should be below the basket), cover and bring to a boil over high heat.

Put 12 crabs in a single layer, shell-side up, on the steamer rack. Sprinkle liberally with about 1/4 cup seafood seasoning. Repeat the process, layering and sprinkling, with the remaining crabs and seasoning. Cover and steam until the crabs are bright orange all over (there should be no traces of blue or green), 20 to 25 minutes.

Transfer the crabs to a large platter or rimmed baking sheet–or spread them out directly on a table covered with butcher paper — and serve with crab mallets for cracking the shells.