Essential oils are obtained through various physical and chemical extraction methods, from various parts of plants, including leaves, flowers, peels, seeds, roots, bark, resin, etc. Prepared by cold pressing.
The most common way of extracting essential oils, suitable for plants that are resistant to heat and will not be destroyed. There are three ways:
- Water Distillation – Immerse plants directly in water and boil them for distillation; this method is most commonly used to extract essential oils from flowers, to prevent the flowers from clumping together during distillation, making it difficult for the vapors to pass through.
- Steam Distillation – In this process, water is placed under the plant to heat, so that the water vapor passes upward through the plant to extract the essential oil, and the water vapor with the essential oil is condensed into a liquid through a conduit, through the difference in specific gravity It can be separated into an oil layer and a water layer, the oil layer is the essential oil, and the water layer is the pure dew (or flower water), which is the most commonly used distillation method.
- Water and Steam Distillation: The first two methods are used alternately.
Cold pressed / Expression
The cold pressing method is used for citrus essential oils or base oils. The peel or pulp is pressed, and water is added to the juice. Finally, the essential oil is separated from the juice (water layer) by centrifugal force. For Examples sweet orange, grapefruit, tangerine, lemon, lime essential oil, etc. It is worth noting that the concept of cold pressing is not in a low-temperature environment, but in a lower operating temperature (40-60°C) compared to general high-temperature extraction.
This method is a very old and traditional method that is no longer available on the market. Apply oil (butter or lard) on the glass frame, then spread the petals on top, use the oil to absorb its essence, and constantly replace the petals until the oil is saturated, and then use alcohol for extraction and separation. The process takes several weeks The above is time-consuming, labor-intensive, and has a lot of costs, so it does not meet the economic value.
The product obtained in this way, called Pomade, can be said to be a very outdated product. Taiwan does not even have a unified translation. Strictly speaking, Pomade can no longer be called essential oil. Compared with the current essential oil products, the concentration is much lower. ; Today, except for a few extraction factories in Grasse, the capital of French perfume, which is extracted by liposuction for tourists to visit, they have generally disappeared from commercial use.
In the movie “Perfume”, there are clips of essential oils extracted by liposuction
Maceration / Immersion / Oil Bubble
The aromatic plants are soaked in hot oil (usually vegetable oil) to rupture the oil cells of the plant, and the hot oil will absorb the released essence, and finally filter and purify it. The oils obtained by the maceration method are called infused oils (Infused Oils or Macerated Oils) and are usually classified as vegetable oils, such as calendula oil, carrot oil, St.
In a broad sense, solvent extraction, in addition to chemical solvents, such as ether, hexane, toluene, formaldehyde, acetaldehyde, alcohol, etc., and even carbon dioxide (CO2), animal oil, vegetable oil, etc., uses the solvency of the solvent to extract plants. Since the boiling point of the chemical solvent is much lower than that of the essential oil, the chemical solvent is finally separated out by means of vacuum distillation (under a low-pressure environment, the boiling point of the solvent can be lowered so that the essential oil molecules are not destroyed).
Usually, after the first solvent extraction (usually with petroleum ether or hexane), the concentration of effective substances obtained is extremely high. After removing the solvent, a wax will be obtained. It contains a lot of waxes, pigments, and fragrances.
→ After taking the condensed body for the second solvent extraction (alcohol), the obtained product is the original essence.
The most common original essences are rose original essence, orange blossom original essence, jasmine original essence, and other precious flowers.
Due to the high solubility of chemical solvents, compared with other extraction methods, the products obtained by solvent extraction methods contain very complete and precious components, and are cheaper than distillation methods, so you can also consider more when purchasing.
Supercritical CO2 Extraction (SFE)
The supercritical CO2 extraction method uses supercritical fluid (Supercritical CO2 fluid, SCF) as solvent extraction, and extracts and separates the extract (such as essential oil) from the matrix (an aromatic plant), which is also one of the solvent extraction methods. At present, it is commonly used in the food industry (such as degreasing, decaffeinate removal, etc.), the pharmaceutical industry (vitamin separation and purification) and the cosmetic industry (ie, essential oil extraction).
The most commonly used supercritical fluid is carbon dioxide (CO2), which has the advantages of colorless, odorless, non-toxic, non-combustible, non-reactive to most substances, and low gas cost; compared with common distillation and solvent extraction methods, there are temperature Low, no solvent residue and other advantages. Common carbon dioxide extraction essential oils include ginger, frankincense, and calendula essential oils. Due to the richer components, the texture is much thicker, and the smell is different from general distillation extraction.