The lobsters start to cook the moment they hit the boiling water. It will take 3 to 4 minutes for the generous amount of water used to return to a boil once the lobsters have been added. That, plus the 6 minutes boiling time called for in the recipe, adds up to a total cooking time of 9 to 10 minutes, the perfect time for a 1 lb. lobster.
Bring 1 1/2 gallons of water to a rapid boil in a very large pot. Add the salt and return to a boil. Add the lobsters, return to a boil, and boil for 6 minutes. Carefully remove the lobsters from the pot and set on dinner plates. Serve with lemon wedges and, if desired, bowls of warm, melted butter.