Extracting essential oils by pressing is an age-old practice. Modern distillers make extracting oil from flowers, leaves, bark and roots of plants very easy. Besides distillation, solvent extraction is also used. They have been used in medicine, cosmetics, household items and flavoring food since long time.
Extracting essential oils requires a distillation process. Many companies use large, centralized equipment. For small-scale and home-based business, smaller decentralized equipment is also available. The distiller is primarily made up of three components: a steam generator, a condenser, and a separator.
A steam generator uses a heat source to boil water and generate steam. The steam, then passes through a small chamber, that holds the particular plant part, and extracts the oils by creating an oil-steam mixture. The condenser cools this mix, and condenses it into an oil-water mixture. Finally, the separator separates the essential oils from the water.
The extraction can be done in four ways, namely, water distillation, steam distillation, dry steam distillation and solvent distillation. Some plants and herbs are just too delicate to handle steam distillation, and need water distillation process to get the right grade of essential oil.
Water Distillation: In this method, water and plant parts are heated in a container to make vapor. When this vapor cools down, it drips into another empty container meant for collecting the essential oil. Water distillation is favored for extracting oil from cinnamon and sandalwood barks.
Steam Distillation: The plant part is placed in a vacuum-sealed container and heated, generating a massive pressure that separates the oil from the particular part of the plant, meant for oil extraction. More care is required, while operating a steam distiller, as the pressure it builds can burst out of the container, if not latched properly.
Dry Steam Distillation: Dry steam distiller has the same operating mechanics, as the steam distiller. However, this is much safer to operate, but, this process can only extract very small amounts of oil.
Solvent Distillation: Certain plant parts do not respond well to any of the methods. For them, a solvent, such as hexane or supercritical carbon dioxide, is used. Here the solvent extracts wax and the essential oil together.
The distillers are available in many sizes. The choice of apparatus differs based on personal requirement. Tabletop or home-grown distillers are meant for home use, and consist of a copper distillation tube, a boiling flask, a receiving beaker, and a condenser. One can extract small amounts of essential oil using this apparatus.
The boiling flask is filled with water and the plant material is heated to make steam. The condenser is attached to the flask with the tube, which in turn is attached to the receiving glass beaker. The receiving beaker is where the extracted oil drips, after it gets strained through the tube.