Distillation with steam
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The process of steam distillation is a very ancient one, and the first distillation machine was created by the Egyptians. But it was the Persian Avicenna who improved this concept by developing one close to that which is still used today. He made the first pure essential oil: the essential oil of roses.
Did you know?
The distillation time and the heating temperature are different depending on the plant to be distilled. Moreover, some plants are distilled fresh and other dried to obtain the best yield of essential oil of the plant in question.
How does the steam distillation process work?
The process consists in heating water in a boiler, the steam passes through a column to where the plant is. By exposure to the plant, the water vapor destroys the plant cells and carries the fragrant molecules with it. The water vapor concentrated with essential oil ends up in a condenser (cooling process) to collect the liquid in what is called a essencier.
Essential oil and water, called hydrolate, do not have the same density and therefore separate in this essencier.
The hydrolate is either recovered or returned to the boiler for a new distillation cycle. It contains much less aromatic molecules than the essential oil, but this is of enough interest in the cosmetic industry.
While essential oils are very stable, hydrolates have a high risk of microbiological contamination.
Essential oils are sensitive to light and heat, which is why they are most often packaged in opaque glass bottles.