According to conventional food cooking practices, crabs are usually placed in the steamer with the lid down when steaming. The purpose of this is to allow steam to enter through the back of the crab so that the crab is heated more evenly and cooked more thoroughly. Also, steaming crabs with the lid down prevents the steam from escaping from the crab, keeping the crab tender. Therefore, steaming crabs with the lid down is in line with the cooking habits and effects of the practice.