There are various methods being employed these days for extracting essential oils from different spices and herbs. The quality of oil extracted depends on the kind of method used for extracting oil. Below are few of the major extraction methods being used these days:

• Steam Distillation : One of the most popular method for extracting oil from spices, the process involves heating the water to produce steam, which is a carrier of volatile chemicals present in the spice. An outside source of steam is used, which is introduced into the distillation unit at a high pressure. The steam is finally condensed and the resulting essential oil is collected separately.
• Hydrodistillation : This is one of the oldest methods of extraction used. The spice is fully immersed in hot water. The result is a soup, which carries aromatic molecules of the plant. The method is not much in use these days, because of the risk of over heating the plant and subsequent loss of the oil. The method is best suitable for spice in dry and powdered form of roots and barks.
• Solvent Extraction : Many herbs and spices cannot be extracted from distillation method, so solvent extraction is the safest method for extracting high quality oil. Spices or herbs to be extracted are washed with a solvent, which dissolves all extractable matter from the plant. These include pigments, volatile molecules and non-aromatic waxes. The herbs and spices are then subjected to low pressure distillation and the volatile oil is then separately collected.
• Carbon Dioxide Extraction : This method is also being popularly used for oil extraction from different spice. Carbon Dioxide in liquid form is used as a inert and safe liquid solvent for extracting aromatic molecules. The process is more advantageous, as there is no residue left at the end of the process. The liquid carbon dioxide simply reverts back to the gaseous state.