Part 1: The Basics of Essential Oil Chemistry
easily separated from the water.
Cold Press is a method that doesn’t involve heat. Cold press
extraction is used exclusively with citrus fruits because it is a way of
extracting oil from the outermost layer of the fruit’s peel. The fruit is
passed across sharp rasping cylinders that abrade the surface of the
peel to break open small essential oil-containing sacs. Water is then
sprayed over the fruit to collect the essential oil. The resulting watery
mixture is then filtered and centrifuged to separate the essential oil
from the water.
Solvent Extraction can be used on every type of plant material, but
is most commonly used on flowers that are too fragile to endure
the conditions required for steam distillation. The plant material is
washed with a solvent to dissolve out the fragrant compounds. The
resulting mixture is then filtered to remove the plant material, and
then the solvent is removed using vacuum distillation. The yield
of this process is a thick, waxy material called a “concrete.” The
concrete is processed again in a similar fashion but with a different
solvent. After another round of vacuum distillation to remove the
second solvent, a pure mixture of only absolute remains. Common
absolutes extracted by this method are Jasmine and Vanilla.
1.3 ESSENTIAL OILS ARE COMPLEX MIXTURES OF
AROMATIC COMPOUNDS
Essential oils are made of volatile aromatic compounds. Volatile
aromatic compounds are small organic molecules that tend to
change from the liquid state to the gas state at room temperature.
These molecules are so incredibly small that a single drop of essential
oil contains around 40,000,000,000,000,000,000 (40 million trillion)
of them. The word “volatile” emphasizes their tendency to evaporate
quickly at room temperature. This property is what makes them smell
so potent. When you first open a bottle of essential oil, you instantly
notice the aroma, and you can smell it even from a distance. The
4