To cook lobster you will need a large pot. Fill the pot with 8 quarts of water and 2 teaspoons of salt, and bring to a boil. For a 1 to 1 1/2 lb. lobster, put the lobster in the boiling water and wait for it to return to the boil. Then, reduce heat and let it simmer for 20 minutes. The lobster will turn bright red when ready.