There are three methods of distillation: water distillation, water and steam distillation, and direct steam distillation. The other methods of Essential oil production are cold pressing, carbon dioxide extraction, enfleurage, solvent extraction, phytonic process, and butane extraction. The type of distillation process used to extract the Essential oil from the plant material is dependent on the part and type of the plant material.
The water distillation process is used on plant material that can’t be damaged by boiling it in water. The plant material is boiled in water. The steam carries the oil droplets to another chamber where the steam is cooled thus changing it to water. The oil separates from the water.
The oil is usually lighter than water so it surfaces to the top of the chamber where it can be siphoned off. The water and steam distillation process is used for plant material that could be damaged by boiling it in water. In this process the plant material is suspended over the water on a type of grate. Low pressure steam passes through the plant material. The steam carries the oil droplets to a condensing chamber. Again the steam is cooled, changing it to water. The oil and water separate with the oil rising to the top. The oil can be removed from the water. The direct steam method is used for fresh plant material that has too high a boiling point such as seeds, roots, or wood. High pressure steam is passed through the plant material.
The steam carries the oil droplets to a condensing chamber where the steam is cooled, changing it to water. The oil can be removed from the water as in the other processes. The cold pressing or expression process is as its name suggests. The plant material usually a fruit or the peel of the fruit are compressed to remove the oil. The oil is then separated from the liquid by high speed rotation. Carbon dioxide extraction uses the unique properties of carbon dioxide both liquid and gas to the advantage of the Essential oil production process. It is this method that allows for the extraction of the “truest to nature” Essential oils. Liquid carbon dioxide is used as a solvent to extract the Essential oil from the plant material. Liquid carbon dioxide changes to a gas when the pressure is decreased. This then leaves only the Essential oil, since the carbon dioxide is now a gas (no residual solvent with the oil). Solvent extraction uses liquids that evaporate easily at low pressures similar to carbon dioxide extraction process. The solvent is mixed with the plant material usually flower petals. The solvent dissolves the Essential oil and then this solution is filtered. The solvent is evaporated at decreased pressure. The residual compound is called a concrete. The concrete still has insoluble vegetable wax with the Essential oil.This product is further processed by solvents and freezing to separate out the waxes. Remaining solvents are removed through a vacuum process that does not require heat.
This final product is called an absolute, highly concentrated oils. Phytonic process is a new method of solvent extraction developed in 1994. Most solvents are chlorofluorocarbons but in this process the solvent is a fluorocarbon named Hydrofluorocarbon 134a. It has the unique properties of not mixing with the Essential oils or dissolving the plant waxes. The plant material and Hydroflourocarbon 134a are mixed together using low pressure. The final product is called phytols, clear liquid Essential oils. This method of extraction does not make a concrete. Butane extraction is a process similar to solvent extracttion however it uses liquified butane gas as the solvent. Butane is mixed with the plant material so that the oil dissolves. Butane is removed with minimal heating (due to its low boiling point) and low pressure vaccum. The product that remains is a concrete. Alcohol is used to remove waxes making the final product an absolute. An absolute made using this process is call a Butaflor. The process of enfleurage is chiefly used to extract oils from flower petals. The flower petals are layered onto warm oils or cold wax. This process is repeated daily until the bottom of the wax is saturated with oil. This compound is called a concrete just as the compounds produced with solvent extraction. The concrete contains 1 percent Essential oil which is removed from the wax using a volitile liquid. The liquid is evaporated at a low temperature and decreased pressure with the remaining product called an absolute.