Essential Oil Extraction

• Distillation is the most common method used to extract an essential oil from its original form. It is not, however, the only method used. Solvent extraction, carbon dioxide extraction and cold pressing are also used. The oils come from aromatic plants and the extraction of the oil can require very delicate handling of the plants in order to be successful. The plants have varying ways and time frames of deterioration. If they are not processed carefully and in a timely manner, the qualities being extracted from them may not be present and the process will be a waste of time. An intricate industry has surrounded this capturing process for centuries. From recognizing the right time to extract, to developing a nose for the right result, to knowing the exact temperatures that work, varying skills are needed for the process to be successful.
  
  

Types of Distillation

• The earliest type of distillation process used is called hydrodistillation. Plants are covered with water, creating a soupy mixture that is then heated. The steam that rises is caught and allowed to settle---it contains the valuable oil. The risk with such a primitive method is overheating and burning, which imparts an offensive smell to the oil. This process is best used on tougher materials like roots and wood. More modern distillation processes use a condenser to capture and cool the steam. The resulting distillate is gathered and the oil is then separated from the water (the hydrosol). The oil usually floats to the top of the hydrosol. Steam distillation uses high pressure to push the steam into and through the plant material and into the condenser taking with it the essential oils. Leaf extraction happens easily through a combination of water and steam distillation. The plant material is hung above the boiling water, allowing the steam vapor to pass through it and taking the essential oils with it.
  
  

Other Extraction Methods

• Delicate plants cannot hold up to the distillation process and must be extracted through solvents. Placed on a perforated tray, blossoms are continually washed with a solvent appropriate for that blossom. The solvent falls through the tray and is captured. The result is a solvent filled with the essential aromatic material, which is then subjected to a very delicate distillation process. A waxy material (called concrete) is produced and further processing using alcohol and then a low temperature freezing removes the waxy matter and separates the essential oil. Three products are actually the result of solvent extraction---the absolute (the oil), the concrete and the floral wax. Floral waxes are sometimes used in candles. Liquid carbon dioxide works as a solvent in a similar process with one exception, it does not produce a residue that needs removal. Cold pressing uses machines to remove citrus oils from rinds and produces a more vibrant and direct result from extraction.