Steaming is a reliable method of cooking small crustaceans because it helps to keep them moist. In a wide shallow pan, bring to a boil ½ in/1.25 cm water (lobsters may need 1 in/2.5 cm) with wine, vinegar, and aromatics such as peppercorns, dill, bay leaf, fennel, star anise, and saffron. Simmer for five minutes, then place a few shellfish at a time on a steamer rack, evenly spaced so that steam reaches each item. Set the rack over the simmering liquid, cover and steam. large shellfish such as lobster and crab are cooked when they turn red (five to ten minutes), small shellfish after three to five minutes and bivalves should be steamed until they open. Serve the shellfish with butter sauce or simply with melted butter.