After watching the movie “Perfume: The Story of a Murderer” again recently, I was once again captivated by its intricate storyline. The protagonist, Grenouille, uses a method both sensual and horrifying to extract scents from young women, prompting one to wonder: can essential oils truly be extracted in such a manner?
In this educational piece, let’s delve into the four primary methods of extracting essential oils.
Perfume’s main ingredients are alcohol, fragrance oils, and water, with essential oils being the core and source of fragrance. There are two main types of fragrance oils: synthetic and naturally extracted. Today, let’s start our journey into the world of perfumery from the harvesting of natural aromatic crops and explore how natural essential oils are extracted and refined.
(For the purpose of this article, “fragrance oils,” “essences,” and “essential oils” all refer to the same substance, hereinafter collectively referred to as “essential oils.”)
Preparation: Harvesting the Raw Materials
The journey from harvesting the plants to successfully extracting essential oils for a small bottle is no easy feat. Aromatic crops from around the world, such as roses from Grasse, lavender from the Mediterranean and Provence, and bergamot from Sicily, require meticulous cultivation and timely harvesting. Only high-quality raw materials can ensure the resulting essential oil’s sufficient quality.
The same plant species grown in different regions may produce essential oils with significantly different aromas due to factors such as climate and soil. For example, while both Damask roses and Moroccan roses belong to the Rosa damascena species, the former tends to have a softer, more elegant fragrance, while the latter’s aroma is brighter. Similarly, compared to Damask roses, Damascus roses have a sweeter, richer scent.
For this reason, luxury brands like Chanel often sign exclusive supply contracts with plantations to ensure that their perfumes have unique and high-quality scents.
Having covered the harvesting of raw materials, let’s now explore how Perfume Essential Oil are extracted.
I. Steam Distillation
In the history of perfumery, steam distillation stands out as the most widely used extraction method. The invention of the distillation apparatus in the 10th century greatly improved the process, marking a significant advancement in perfume history. Common essential oils such as lavender, chamomile, peppermint, and rose are all obtained through steam distillation.
Steam distillation is a relatively simple process. Plant material is heated by steam, which carries the essential oil components of the plant. After the steam enters the condenser, it condenses into a liquid and then enters the separator. Because essential oils are insoluble in water, lighter essential oils float on top in the separator, while heavier ones sink to the bottom, thus separating the essential oils.
The remaining water from the distillation process still contains aromatic compounds, making it a common product in the market known as hydrosols. Hydrosols have various beauty benefits and are used for facial treatments, hair care, and bathing with excellent results.
II. Enfleurage
As one of the oldest extraction methods, enfleurage has evolved over time to become the precursor of solvent extraction. Currently, this method is rarely used, with only Grasse, France, still employing this traditional enfleurage technique.
Enfleurage is primarily used to extract fragrance from expensive plant flowers such as jasmine and rose. Taking advantage of the property that volatile aromatic molecules can dissolve in fats, fresh flowers are placed on wooden boards saturated with oil (animal or vegetable). As the flowers naturally dry, the aromatic compounds are absorbed by the fat. The process is repeated with fresh petals until the fat is fully saturated with fragrance. Impurities are then removed from the fat, and it is washed with alcohol. After the alcohol evaporates, the essential oil from the flowers is extracted.
So, is it feasible to use enfleurage to extract the body scent of young girls, as depicted in the movie “Perfume: The Story of a Murderer”?
Absolutely Not!!
This is because the body odor of humans originates from the secretion of sebaceous glands and bacteria, with the secretion itself being almost odorless. Body odor is primarily produced by bacteria. Different secretions, temperatures, and humidity determine the types of bacteria present, resulting in different odors.
In the movie, the protagonist attempts to extract the body and hair oils from young girls using enfleurage. While the body’s secretions indeed contain lipid-soluble aromatic components, their concentration is extremely low. It would be impossible to extract a small bottle of essential oil from dozens of young girls. Therefore, in practical terms, this method of extracting body scent is not viable.
III. Solvent Extraction Method
Some delicate plants, such as hyacinth, daffodil, and tuberose, cannot withstand the high temperatures of steam distillation. Therefore, solvent extraction method is commonly employed for extraction.
The solvent extraction method primarily utilizes volatile solvents like hexane or diethyl ether. These solvents are used to repeatedly wash the petals, allowing the aromatic compounds from the petals to transfer to the solvent. The solvent is then distilled, and after separation, a semi-solid substance called concrete containing volatile oils is obtained.
Concretes can be used as solid perfumes themselves, but they are often further processed. The concrete is dissolved in ethanol, cooled, filtered to remove impurities, and then subjected to vacuum distillation to recover the ethanol. The resulting product is called an absolute. Absolutes are a type of essential oil, characterized by their high purity and thus command a higher price compared to essential oils extracted using other methods.
IV. Carbon Dioxide Extraction Method
Carbon dioxide extraction method, also known as “supercritical extraction,” primarily involves the extraction of essential oils through the interconversion of carbon dioxide between liquid and gas phases.
In this method, carbon dioxide is compressed into a liquid state and used as a solvent. Natural plant material is immersed in this liquid carbon dioxide, allowing the volatile essential oils to dissolve. The liquid carbon dioxide is then converted back into a gas phase, separating the essential oils.
Carbon dioxide extraction is highly efficient and leaves no solvent residues. The resulting aroma is also closer to the natural scent of the plants. However, this extraction method requires complex and expensive equipment. Additionally, the closer resemblance to natural aromas often means an increased risk of irritation for sensitive skin, making this method less common.
V. Cold Pressing Method
Citrus essential oils are predominantly found in the peel of fruits such as oranges, bergamots, grapefruits, lemons, and others. Since fruit peels cannot withstand high-temperature steam, cold pressing is commonly used for extraction. Due to variations in the pressing method, cold pressing is generally divided into three types: sponge method, pricking method, and centrifugation method.
The first two methods, sponge and pricking, are outdated and labor-intensive, and are rarely used today. Therefore, we will focus on the centrifugation method, which is the most common technique employed nowadays.
The centrifugation method has been improved upon the shortcomings of the former two methods. It involves placing the fruit peels into a high-speed rotating machine with spiral grooves and spikes, followed by filtration of the extracted oil to remove impurities. Subsequently, a centrifuge is utilized to separate the essential oil from water based on their differing densities, making the process more efficient and less labor-intensive.
Conclusion:
The history of perfume development unfolds like a magnificent tapestry, with the extraction methods of essential oils serving as decisive strokes. These 5 extraction techniques cater to various aromatic plants, each with its own advantages and drawbacks, representing the culmination of countless trials by past experts and advancements in technology. Let us traverse through time and space, relishing the beauty recorded by perfumers over the centuries, awakening memories long forgotten.
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