Today, most common essential oils, such as lavender, peppermint, and eucalyptus, are distilled. Raw plant material, the flowers, leaves, wood, bark, roots, seeds, or peel, is put into a distillation apparatus over water. As the water is heated, the steam passes through the plant material collecting the scents. The steam flow through a coil, where it is condensing back to liquid, which is then collected.