Distillation is the main method of extracting essential oils from plant bodies.
Distillation is the only method to extract essential oils
In fact, according to many pharmacopeias, distillation is the only method of extracting essential oils, and those obtained by other methods are called essences or raw essences.
To perform the distillation method, the plant tissue must be heated, which is done in two ways.
- Placing the plant tissue in water, which is then heated to boiling.
- Placing the plant tissue on a rack or net and heating the water beneath the plant, allowing the steam to pass through the plant tissue. Leaves, branches, berries, petals, and other plant tissues can be distilled.
What are the different forms of distillation methods?
The method of putting plant tissues into water is called direct distillation.
And the other method, which allows steam to pass through plant tissue placed on a grid is called steam distillation.
Both of these distillation methods allow the cell walls of the plant cells to rupture, releasing the essence stored in the cells as steam.
The vapors from these essences are mixed with water vapor and together they enter a cooling tube before returning to a liquid state and finally being collected in a larger bottle.
The water vapor condenses into water, while the essence condenses into essential oil. Essential oils are lighter than water, so they can be easily separated and collected from the water layer.
Some of the aqueous layers also have a high value and can be sold under the name “floral water” or “herbal water”. The French call these distilled liquids “pure dew”.
There are some plants where distillation does not extract much essential oil but produces by-products, such as rose puree or neroli puree.
In this case, sorption or solvent extraction can be used to extract the essences from these by-products, as well as to extract the essences contained in the delicate petal tissue.
Distillation technology is constantly improving
Distillation techniques were well developed as late as the 10th century, and people were known to use distillation to extract essential oils.
The origin of the distillation technique was probably Persia when people used these essential oils as perfumes.
However, recently archaeologists have unearthed some distillation apparatus in Italy. These antiquities prove that the Romans already knew about distillation and that the Persians adopted their technique.
In the more technologically backward areas and in the small-scale European countryside where essential oils are produced, the distillation apparatus used today is similar to that used in the past.
In areas where essential oils are produced on a large scale, people have made distillation apparatus larger and more complex, but the basic principles are still the same.
Most modern apparatus are made of stainless steel to avoid contaminating the distilled essence and to guarantee the quality of the essential oil (although this is not proven).
The ability to produce good quality essential oils suitable for aromatherapy is very closely related to the distillation technique.
The temperature of the distillation, the time of distillation, and other factors are closely related to the quality of the essential oil.