To create löyly steam, a bucket of water (often containing fragrant essential oils) is carried into the sauna and ladled over the hot stones on the sauna heater. This fills the sauna with a cloud of fragrant löyly steam. As the level of humidity in the sauna rises sharply, you suddenly feel intense heat. This sensation is further enhanced by swirling the humid air around the room with a towel. Pouring water over the stones provides an additional heat stimulus which gets your sweat glands working overtime. During the procedure, the door of the sauna should not be opened. Water is generally poured over the stones towards the end of your sauna round – the crowning glory, so to speak, of your sauna experience.