The definition of an essential oil, which was adopted by the International Standards Organization (ISO) at the 9th Plenary Meeting of the Technical Committee ISO/TC54 Essential Oils, held in Lisbon, 5th-9th March, 1968, was:
Essential oils are volatile oils, generally odorous, which occur in certain plants or specified parts of plants, recovered by accepted procedures such that the nature and composition of the product is, as nearly as practicable, unchanged by such procedures.
"This is an important definition. It specifies clearly that the nature and composition of the oil must be unchanged by the process of extracting it and is therefore one reason why steam distillation is an appropriate method of extraction. Furthermore, because steam distillation has been the extraction method for most essential oils, the market accepts steam distilled oil as normal oil.
Oil derived by another technique might be of slightly different chemical composition and therefore might not be accepted by the market."
- Department of Trade and Industry Document South Africa Dec 2004
Components of a Distillation Unit
1. Steam Generator or Boiler
The boiler or steam generator supplies the steam for the system and each plant material has its own steam flow rate.
Fuel source can vary due to customers various circumstances and preferences.
Over the years we have built up relationships with suppliers and can supply boilers for you at completive rates or use an existing steam source.
Please note boilers fall under government laws as they are pressurised vessels and have to be inspected on a continuous basis. They are normally the only thing that can go wrong with our machines and this is why we normally work with your countries suppliers and adhere to your rules and regulations that these pressure vessels fall under.
Should a problem occur with the boiler your supplier is close at hand.
Please see your government gazette for these laws.
Classed as a steam generator, if it operates at atmospheric pressure, it therefore does not fall under and governing laws as boilers do.
We also supply pressurised electrical boilers and they are classed as boilers. They need to be inspected regularly by an inspector in your country.
They require a specific water type
These electrical boilers are easy to clean and service.
Diesel or LP Gas
Diesel or gas boilers fall under the laws and need to be inspected by government officials.
They normally need to pass an inspection when installed.
They are harder to clean and to do maintenance on.
They cannot handle certain water types
Wood or Bio Mass
2. Heat Exchanger
The heat exchanger turns steam and the volatile oil gas back into water. Designed for the machine's steam flow rate, plant material and water quality.
The Separator separates the oil and hydrosol. Designed for the machine's flow rate and plant material used. Some oils sink and some float and some do both.
Separators are available for oils heavier than water.
The size of the still is determined by the plant material. E.g. lavender has a window period and all material has to be harvested in a short time, which increases machine size and boiler steam flow rate.