Steam Distillation Steam distillation is the most common method of extracting essential oils. Many old-time distillers favor this method for most oils, and say that none of the newer methods produces better quality oils.
Steam distillation is done in a still.
Fresh, or sometimes dried, botanical material is placed in the plant chamber of the still, and pressurized steam is generated in a separate chamber and circulated through the plant material. The heat of the steam forces the tiny intercellular pockets that hold the essential oils to open and release them. The temperature of the steam must be high enough to open the pouches, yet not so high that it destroys the plants or fractures or burns the essential oils. As they are released, the tiny droplets of essential oil evaporate and, together with the steam molecules, travel through a tube into the still's condensation chamber. As the steam cools,it condenses into water.