Extraction of Essential Oils
A classic example is the orange tree, which gives us three wonderful and unique oils.
The peel of the orange fruit gives us orange oil, the leaf from the same tree provides Petit grain oil and the flowers give us Neroli oil, commonly called Orange Blossom oil. All these oils are extracted via different methods from the same tree.
Extracting the oils from their source is the first step in the process of bottling essential oils. Specific methods are best suited to extract the oil from different sources.
1) Cold Press Method
One of the simplest methods of oils extraction,this is used mostly for citrus family fruits.
The process, as the name suggests, involves taking the peel of the fruit (orange, lemon, lime, grapefruit) and mechanically crushing it to extract the oil present in the small pouches giving access to the pure oil. It is called cold press extraction as no heat is involved in the only disadvantage of this method is the oil extracted is highly volatile and has a very short shelf life of only 6 to 12 months.
2) Solvent Extraction
This method is mainly used for flowers where it becomes very difficult to extract their oils through any other method.
Freshly plucked flowers are put into huge metal containers and a highly deodorized solvent, such as hexane, is poured over it. The solvent extracts the wax from the flowers and is then taken for vacuum processing which separates the solvent from the wax. The solvent is then reused. The remaining wax is called concrete,which contains a high percentage of essential oil. After this step, the absolute alcohol is used to separate oil from the wax and what you get are oils that are called absolute. To technically differentiate the extraction process the word absolute is used after the name of the plant (generally flower) oil.
3) Steam Distillation
All other types of essential oils are extracted by this method. This is the most common method of extraction for essential oil from leaves, grass, roots, berries and other parts of plants.
Steam from boiling water is passed through the raw material, which drives out most of their volatile fragrant compounds. The condensate from distillation, which contains both water and the aromatic molecules, settles in a florence flask. This allows for easy separation of the fragrant oils from the water as in most cases the oil will float to the top of the distillate from where it is removed, leaving behind the water distillate. The water collected from the condensate, which retains some of the fragrant compounds and oils from the raw material, is called hydrosol and is sometimes sold for consumer and commercial use or is retrieved for reuse.
The yield from different plant varies from 0.02% to an average of maximum 2% of means, when you take about 40 rose flowers you will get only 1 drop of oil and in the case of lavender you will get about 2 ml of oil from 100g of flowers. Prices of plant material vary to a great extent and its yield also differs. Hence the prices of different essential oils are very disparate.
People all over the world are becoming aware of the powers of essential oils and their therapeutic benefits. Owing to which, the popularity of essential oils has increased manifolds in the past few years, irrelevant of the cost involved.