Why Steam Distillation for Essential Oils?
Although there are other techniques, Steam Distillation remains the preferred process for the extraction of essential oils from plant material.From the consumer's point of view, the simplicity and transparency of the process gives reassurance of purity, as the process uses only water. From a commercial point of view, the ability to process large quantities of material with a technique that requires relatively modest investment and skill levels is attractive.
The Process
The steam distillation process for the extraction of essential oils from plant material consists of 3 basic parts - the retort, the condenser, and the separator.Overview : The Three main Components
c.chamomile.co.uk 1996/2006The Retort or Still
This contains the plant material containing the volatile essential oil.High pressure steam is passed in at the base into a void beneath a perforated grid which supports the charge of green herb.The steam passes through the plant material heating and saturating it with water.The resulting vapour, a mixture of steam and essential oil vapours, passes out at the top and is conveyed to the condenser.
Click for more information on : Retort DesignsThe Condenser
The vapours from the retort are cooled by passing down a long spiral or bundle of tubing or plates cooled by being immersed in a flow of water.
The condesate runs by gravity ino a container in which the oil and water separate by virtue of their differing specific gravities in the separator.
Click for more information on our : Standard Range of CondensersThe Separator
The mixture of condensed oil and water runs into the separator where the lighter insoluable oil floats on the surface, accumulates slowly and is drawn off periodically. This is the essential oil
The water - or rather water containg the more water soluable constituents extracted by the steam, known as the hydrolat or floral water - is drawn off continuously from the bottom of the separator.