The way in which oils are extracted from plants is important because some processes use solvents that can destroy the therapeutic properties. The usual method of extraction is through steam distillation. After extraction, the properties of a good quality essential oil should be as close as possible to the “essence” of the original plant. The key to a ‘good’ essential oil is through low pressure and low temperature processing. High temperatures, rapid processing and the use of solvents alter the molecular structure, will destroy the therapeutic value and alter the fragrance. Other processes include expression, or solvent extraction. They are used in perfumes and cosmetics, for flavoring food and drink, and for scenting incense and household cleaning products. There are many ways in which essential oils are extracted. The vast majority of true essential oils are produced by distillation. Distillation is a method of separating chemical substances based on differences in their volatilities in a boiling liquid mixture.
The mixture of water and essential oil is collected in the “essencier” where the two elements decant and separate due to their different densities – the essential oil is lighter and rises to the top, floating above the aromatic water. Steam distillation uses an outside source of steam which pipes the steam into the distillation unit, sometimes at high pressure. The steam passes through the aromatic material, and exits into the condenser. Another method is essential oil extraction is Pomades. Pomades are produced using a process known as enfleurage, which is seldom done today. Various essential oils have been used medicinally at different periods in history. Medical applications proposed by those who sell medicinal oils vary from skin treatments to remedies for cancer, and are often based on historical use of these oils for these purposes. Such claims are now subject to regulation in most countries, and have grown correspondingly more vague, to stay within these regulations.
Essential oils are extracted from many different parts of their plants. For example, Lavender is extracted from its flowers, Orange from the rind of its fruit, Frankincense from the resin of its tree, Cinnamon from its bark, Pine from its needles, and so on.
Pressing is a simple method of squeezing out literally, essential oils from the rinds and peel off ripe fruit such as orange and lemon into a sponge. Solvent extraction is used in combination with distillation. A hydrocarbon solvent is put in with the plant material and dissolves the essential oil. The resulting solution is then filtered and put through a distillation process that concentrates the oil to produce a resin, or resinoid.
Essential Oil Extraction – Enfleurage
This is the method by which flower essences such as Jasmine, Rose, which are more delicate and difficult to obtain are extracted. Flowers or petals are crushed between wooden framed, glass trays smeared with a greasy animal fat until the fat is saturated with their perfume.
Essential Oil Extraction – Pressing
This is a simple method of squeezing out literally, essential oils from the rinds and peel off ripe fruit such as orange and lemon into a sponge.