" What is the difference between essential oils and hydrosols?
The tools of Aromatherapy are essential oils and hydrosols. Essential oils, non-oily in texture, are obtained from plants by a process called distillation, where selected plant materials are heated with water (or steam, or both) in an enclosed still, so that their volatile components are released from the plant. The components vaporize and are then present in the steam. The steam/vapor then condenses back to a liquid state. Due to differences in density, the essential oil separates from the water. The separated water contains water-soluble essential oil components and is termed the hydrosol or hydrolate. The term essential oil also usually includes the group of mechanically pressed citrus oils.
Essential oils are the highly concentrated, volatile, aromatic essences of plants. Scientists agree that essential oils may perform more than one function in living plants. In some cases they seem to be a part of the plant's immune system. In other cases they may simply be end products of metabolism. Essential oils can contain hundreds of organic constituents, including hormones, vitamins and other natural elements that work on many levels. They are 75 to 100 times more concentrated than the oils in dried herbs. "