PRODUCTION OF ESSENTIAL OILS

Have you ever wondered about how to make essential oils? Let us explain that Essential Oils are not made, but instead, they are extracted from plant materials. Extractions are used to obtain a plant’s active botanical constituents that function as its “life force.” They are essentially the liquefied version of a plant, and they effectively allow its beneficial compounds to reach the blood stream faster than they would by simply consuming the plant.

An herbal extract is produced when a botanical material is introduced to a solvent in which some of the plant material components dissolve. Ultimately, the solvent becomes infused with the botanical materials that it has pulled from the source plant, and this is what is referred to as the “extract.” The solution that remains at the end of the process can be liquid, or the liquid can be removed to turn the remnants of the botanical into a solid. The solvents can act as preservatives or as agents that help plant cells to break down and release their contents.

ESSENTIAL OIL STEAM DISTILLATION

Steam Distillation is the most popular method used to extract and isolate essential oils from plants for use in natural products. This happens when the steam vaporizes the plant material’s volatile compounds, which eventually go through a condensation and collection process.

STEAM DISTILLATION PROCESS FOR ESSENTIAL OIL

A large container called a Still, which is usually made of stainless steel, containing the plant material has steam added to it.

Through an inlet, steam is injected through the plant material containing the desired oils, releasing the plant’s aromatic molecules and turning them into vapor.

The vaporized plant compounds travel to the condensation flask or the Condenser. Here, two separate pipes make it possible for hot water to exit and for cold water to enter the Condenser. This makes the vapor cool back into liquid form.

The aromatic liquid by-product drops from the Condenser and collects inside a receptacle underneath it, which is called a Separator. Because water and oil do not mix, the essential oil floats on top of the water. From here, it is siphoned off. (Some essential oils are heavier than water, such as clove essential oil, so they are found at the bottom of the Separator.)

SOLVENT EXTRACTION OF ESSENTIAL OIL

This method employs food grade solvents like hexane and ethanol to isolate essential oils from plant material. It is best suited for plant materials that yield low amounts of essential oil, that are largely resinous, or that are delicate aromatics unable to withstand the pressure and distress of steam distillation. This method also produces a finer fragrance than any type of distillation method.

Through this process, the non-volatile plant material such as waxes and pigments, are also extracted and sometimes removed through other processes.

Once the plant material has been treated with the solvent, it produces a waxy aromatic compound called a “concrete.” When this concrete substance is mixed with alcohol, the oil particles are released. The aforementioned chemicals used in the process then remain in the oil and the oil is used in perfumes by the perfume industry or for aromatherapy purposes.

CO2 EXTRACTION OF ESSENTIAL OIL

Essential oils derived from the supercritical CO2 extraction of herbs are similar to the oils produced through distillation in that they can be used in aromatherapy and natural perfumery.

Oils derived from steam distillation vary in their qualities depending on the temperatures, pressures, and length of time applied for the process. The CO2 extraction process might thus produce higher quality oils that have not been altered by the application of high heat, unlike the steam distillation process. In CO2 extraction, none of the constituents of the oil are damaged by heat.

Thus, the difference between traditional distillation and supercritical extraction is that instead of heated water or steam, CO2 is used as a solvent in the latter method. The supercritical extraction process operates at temperatures between 95 to 100 degrees F whereas steam distillation operates at temperatures between 140 to 212 degrees F.

In steam distillation, the molecular composition of both the plant matter and the essential oil are changed due to the temperature applied. On the other hand, a CO2 extract is closer in chemical composition to the original plant from which it is derived, as it contains a wider range of the plant’s constituents.

For example, CO2 Extraction of German Chamomile flowers yields a green extract, because the absence of heat means it was not altered from its natural state or “denatured.” The resulting extract is thus more similar in composition to the original flower than the distilled essential oils is.

CO2 extracts are usually thicker than their essential oil counterparts and often give off more of the aroma of the natural herb, spice, or plant than a distilled essential oil. CO2 extracts have been said to contain more plant constituents than the amount extracted from the same plant using steam distillation.

THE CO2 EXTRACTION PROCESS

Pressurized carbon dioxide becomes liquid while remaining in a gaseous state, which means it is now “supercritical.” In this state, it is pumped into a chamber filled with plant matter.

Because of the liquid properties of the gas, the CO2 functions as a solvent on the natural plant matter, pulling the oils and other substances such as pigment and resin from the plant matter. The essential oil content then dissolves into the liquid CO2.

The CO2 is brought back to natural pressure and evaporates back into its gaseous state, while what is left is the resulting oil.

WATER DISTILLATION

Delicate flowers such as roses and orange blossoms would clump together when introduced to steam in the distillation process, so the most effective method of extraction in this situation is to submerge fragile plant material in pure boiling water instead. The water protects the extracted oil from overheating. The condensed liquids cool down and separate from each other. The remaining water, which can sometimes be fragrant, is referred to by several names including hydrolate, hydrosol, herbal water, essential water, floral water, or herbal distillate.