Essential oil is a general term used to define a large variety of aromatic products like essences, resinoids, concretes, absolutes, etc. The main aim of any extraction process is to obtain the oils from the aromatic essence molecules of a particular plant. These molecules are present in different parts of each plant. Lavender oil is extracted from the lavender flower, orange from the rinds of the fruit, cinnamon from the bark of the tree, pine from the needles of the pine tree, and so on.
Steam Distillation Process
This is the most popular, and at the same time, the oldest method to make essential oils. It is believed that this method of extraction started as early as the 8th century. Many people opine that the quality of essences extracted through this technique is most superior. It can be used to extract oil from roots, stems, seeds, leaves, and flowers. Aromatherapy uses oils are extracted with the help of this method.
Two large containers are used in this method. The first container holds steamed water and the raw material from which the oil has to be extracted. This is then heated at a low pressure. Due to the simmering heat, the oils are released into the water, and change into vapor. This extracted oil is then passed on to the second container through a vent. The cold water present in the second container converts the vapor of the oil into liquid. Then, the mixture of oil and water is made to pass through an alembic so that the oil separates from water. Apart from the oils, you also get another by-product at the end of this process. Rose water, orange water, and lavender water are those obtained after their floral distillation process.
A thick layer of vegetable oil is applied on a glass sheet, which is then placed on a wooden rack. Then, the flower petals are kept on the glass, and it is placed under the sun. Due to the heat of the sun, the oil of the flowers gets extracted, and mixes with the vegetable oil. Once the vegetable oil gets saturated with the essence of the flowers, the mixture is dissolved in alcohol, and left untouched. When the alcohol evaporates, the oil is obtained in its purest form. Sometimes, animal fat is also used in place of vegetable oil.
Solvent Extraction Process
This is another method which is good for extraction of oil from delicate flowers. For this process, hydrocarbon solvents like petroleum ether are used. The flower petals are kept on a metallic tray with perforations. The solvent is sprayed on, and absorbed by the petals. As a result, the essence of the flower gets released. Then, alcohol is added to the concentrated essence. When the alcohol dries up, the fatty substances are removed, and the essential oil is left behind.
Maceration process not only extracts the essences, but also to create resins. It is similar to the enfleurage process. The raw materials are soaked in vegetable oil, which is then heated artificially to extort the oils. The vegetable oil is then strained. This oil is often used for body massages. When instead of vegetable fat, other solvents like water or alcohol are used for soaking the plant matter, then a thick extract or resinous substance is obtained at the end of the process.
The quality of essential oil mainly depends on the method used to extract it. It also largely depends on the quality and quantity of the raw material used for the extraction process. Good quality raw material is ensured if the soil is good, and the plant is grown in a geographic location where the climatic condition is suitable for the plant.