Published on: 07/23/ 2009 | By: Alex Quek
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About The Author: Mr Alexander Quek Poh Liak, graduated in 1986 from Kolej Tunku Abdul Rahman, Kuala Lumpur with a Diploma in Science (with Distinction in Chemistry and Mathematics) and a Bachelor
of Science Degree (Magna Cum Laude) from Campbell University, North Carolina, USA.
He has more than 20 years experience in the Chemical Industry, especially in Personal Care and Household Care industries. Website URL: http://www.alexquek.com
The plant is heated by water or steam in a still which causes the cell structure to rupture and frees the essential oil.
The steam carrying the aromatic molecules is cooled to produce a mixture of oil and water.
The essential oil is then separated and bottled.
Expression Process
This method of extraction is employed for obtaining oil from citrus fruits such as bergamot, grapefruit, lemon, lime, orange, mandarin and tangerine, as their oil is present in the rind of the fruit.
The expression process was originally carried out by hand, but now mechanical presses are employed.
Other Processes
Other processes do not yield true essential oils:
Solvent (alcohol, benzene, hexane) extraction which produces absolutes, concretes and resinoids.
Enfleurage (infusion with fat) which produces pomades and then enfleurage absolutes. This process is virtually obsolete today.
Other Processes (latest)
Percolation (hydrodiffusion) whereby steam at atmospheric pressure disperses throughout the plant material from the top of the plant chamber.
Turbodistillation extraction whereby the plants are soak in water, and steam circulates through this plant-and-water mixture.
