• Every substance boils at a different temperature. This allows the process of distillation to purify drinking water, oils, medicines, and more. Distillation can eliminate germs, poisons and even heavy metals from water. Steam distillation is a slightly more high-tech, and faster, version of the classic methods of distillation. It extracts essential oils from plants that might break down under normal distillation methods and produces a higher, purer, end product. It is also used to refine petroleum and other chemicals.
  
  

Water-Steam Method

• There are two major methods of steam distillation. One is the water-steam method. It is superior to the usual water distillation method, as it won't break down essential oils or other chemicals as readily. With this method, the material to be distilled is suspended above boiling water. Steam rises and mixes with the material.
  
  

Steam Method

• The other main way to steam distill is the "steam method." An external boiler supplies live steam directly to the mixture to be distilled. Live steam is steam that has been heated above its boiling point, and is very hot and fast-moving.
  
  An example is the extraction of essential oils from an herb. The herb is affixed to a wire mesh above the source of the steam. As the steam travels over the herb, it heats the herb. The herb's essential oils are vaporized and rise with the steam to the top of the container, where they condense back into oil and water. These collect in a receiving flask and are separated later.
  
  

Variant Steam Method

• A variation of steam distillation distills liquid instead of solid materials. This liquid is usually a solution of one or more other liquids with solids dissolved in them. It uses a special flask that forces steam to bubble through the liquid in the flask.