Distillation & Extraction of Jasmine Oil
The sheer difficulty of extracting jasmine oil from the flower petals requires that a very sophisticated process must be used. Steam distillation, the extraction method used most commonly to create essential oils, uses high heat that can cause the delicate petals to deteriorate and form a dense mass that steam cannot penetrate, rendering the precious oil impossible to extract from the petals. Also, because steam distillation relies on water, many water-soluble chemicals present in the petals are lost in the process, creating a different scent profile than that found in the actual flower. Finally, the heat involved in steam distillation can denature the delicate aromatic molecules present in the flower, and almost all the fragrance is lost.
For these reasons, it is clear that steam distillation is not an appropriate method of extraction for jasmine oil. The most efficient method to extract jasmine oil from the delicate flowers has been researched since the 1970’s. However, low efficiency and yield continue to plague the production of the expensive jasmine oil. The final product, regardless of the method employed, tends to have resultant quality issues, such as solvent residues and other impurities which tend to distort the true aroma.
Two-step Solvent Extraction
The most common method currently used to coax the precious jasmine oil from the delicate petals without damaging the fragrance molecules is by producing an absolute, a highly concentrated, entirely alcohol-soluble, liquid extract. (Arctander, S. (1960) Perfume and Flavor Materials of Natural Origin. Artander). A two-step chemical process called solvent extraction is typically employed to create the concrete and then the absolute.
The first step of creating jasmine absolute is to produce what is called a ‘concrete’ by extracting the oil from the flower petals using a solvent such as hexane or similar purified chemical solvents. Different solvents can produce drastically different oil yields due to their polarities, as one study found that 95% ethanol produced higher yields than diethyl ether, which in turn produced higher yields than hexane. However, the tradeoff appears to be that ethanol may be so effective at extraction that it pulls non-volatile compounds out of the flower petals in addition to the fragrant volatile chemicals, creating a less pure oil that typically does not have a ‘true’ scent, or requiring further steps to attenuate the inferior oil. (Paibon, W., Yimnoi, C. A., Tembab, N., Boonlue, W., Jampachaisri, K., Nuengchamnong, N., et. al. (2011). Comparison and evaluation of volatile oils from three different extraction methods for some Thai fragrant flowers. J Cosmet Sci. 33(2): 150-6. doi: 10.1111/j.1468-2494.2010.00603.x.)
In solvent extraction, the delicate flower petals are carefully placed in thin layers onto circular, perforated trays arranged on racks. These racks are then placed inside a cylindrical drum along with the solvent of choice. The drum rotates slowly, allowing the solvent to penetrate the petals and efficiently remove the fragrance molecules. The longer the solvent is in contact with the flower petals, the longer time available for the volatile chemicals to rise to the surface of the flower petal and diffuse throughout the solution. Thus, there is a significant positive relationship between the amount of time the solvent is allowed to remain in contact with the flower petals and the direct yield of oil. (Paibon, W., Yimnoi, C. A., Tembab, N., Boonlue, W., Jampachaisri, K., Nuengchamnong, N., et. al. (2011). Comparison and evaluation of volatile oils from three different extraction methods for some Thai fragrant flowers. J Cosmet Sci. 33(2): 150-6. doi: 10.1111/j.1468-2494.2010.00603.x.) In addition, two solvent washes are typically performed in an effort to extract as much aroma as possible.
The solvent is then evaporated by distillation, until a highly aromatic, waxy substance is left behind, called a concrete. Jasmine concretes are essentially semi-solid to solid waxes that contain pigments ranging from yellow-brown to dark orange. It takes 1000 pounds of jasmine petals (about one million flowers!) to eventually create one pound of jasmine concrete. From this point, the concrete is either used to make solid perfumes that have a slightly more fruity aroma than typical jasmine, or continues to the second phase of solvent extraction. Concretes have the benefit of being long lasting in their wax form, although they don’t have as highly concentrated aroma profiles as an essential oil (typically only 0.2% - 5.5% aromatic molecules). However, they are also difficult to use unless one has adequate knowledge of how to use an oil with such a thick, heavy consistency. Thus, typically the concretes are processed further to remove the ‘absolute,’ which composes approximately 50% of the concrete. (Arctander, S. (1960) Perfume and Flavor Materials of Natural Origin. Artander)
During the next step of the two-step solvent extraction process, a form of grain alcohol, such as pure sugar cane alcohol is added to the concrete in order to remove nearly all of the pigments and waxes until only the aromatic absolute is left behind. The mixture is brought to a temperature of approximately 115-140 degrees Fahrenheit. Most of the alcohol-soluble aromatic molecules quickly separate from the waxy substance, although the mixture must be frozen and shaken or stirred to completely remove most of the final traces of waxy material. Occasionally, multiple extractions from the concrete will take place until the resulting absolute has absorbed all of the aromatic principles. (Arctander, S. (1960) Perfume and Flavor Materials of Natural Origin. Artander).
Finally, the alcohol is gently vacuum distilled off and time is given to allow most of the alcohol to evaporate from the solution, leaving behind a slightly viscous jasmine absolute that is typically a dark orange to reddish orange color. Absolutes have the benefit of being the most concentrated form of a natural fragrance, lending a very close scent profile to the original jasmine flower. The absolute has been described as having a ‘’peculiar, waxy-herbaceous, oily-fruity, and tea-like undertone.” (Arctander, S. (1960) Perfume and Flavor Materials of Natural Origin. Artander) However, absolutes still contain trace amounts of alcohol (approximately 2-3%) pigments, and waxy substances leftover from the original concrete.
Similar to other essential oil profiles, jasmine oil contains over one hundred chemical constituents. However, it’s major components consist of benzyl acetate, linalool, cis-jasmone, indole, and methyl anthranilate. Other components include:
Benzoic acid, benzaldehyde, benzyl alcohol, benzyl benzoate, cis-3-hexenyl benzoate, ceosol, eugenol, farnesol, geraniol, p-cresol, nerol, gamma terpineol, nerolidol, isohytol, phytol, methyl benzoate, (E,E)-alpha-farnesene, (Z)-jasmone
tricosane, (Z)-methyl jasmonate, (Z)-isoeugenol, methyl octadecanoate, methyl 9-decenoate, methyl linoleate, (E)-phytol, plamitic acid, y-terpineol, (E)-nerolidol, heneicosane, hexahydrofarn3esyl acetone, (Z)-3-hexenyl benzoate, methyl hexadecanoate, tricosane, methyl jasmonate, linalyl acetate, benzyl alcohol, jasmone, racemic (5-pent- 2-enyl)-5,1-pentanolide, 1-α-terpineol, γ-jasmolactone, isophytol acetate, β-γ-hexenal and oleacin.
(Arun, M., Satish, S., & Anima, P. (2015). Phytopharmacological Profile of Jasminum Grandiflorum Linn. (Oleaceae). Chinese Journal of Integrated Traditional and Western Medicine. DOI: 10.1007/s11655-015-2051-3)
Organic Jasmine Extract
A recent method has been created in order to produce an extract that can receive the title ‘organic extract’ as long as all materials used to create the extract are certified organic.
This begins with using certified-organic jasmine flowers in the following manner: plants are grown without the use of chemical pesticides, herbicides, or fertilizers or any other artificial or polluting agents (e.g. composts made with urban/sanitary sludge) added into the soil. The manufacturing process (e.g. distillation, expression, extraction.) must also be approved by the organic certification agency. Then, the solvents themselves must be organic, using certified oil and organic alcohol or other similar organic certified solvents.
The final jasmine organic extract from the Jasminum officinalis flowers is substantially different than jasmine absolute, in that the organic extract is green in color, softer in fragrance and has a more green, animalic, honey-like nuance to the aroma. Jasmine absolute is typically not accepted for use in true aromatherapy (due to the remaining solvents in the absolute), however aromatherapists are able to use jasmine organic extract for therapeutic uses.
CO2 Supercritical Extraction
A newer and more efficient way of extracting jasmine oil is by use of CO2 supercritical extraction. Typically, this is carried out by using pressurized CO2 to extract a viscous oil from the jasmine concrete. The jasmine CO2 extract that results from using this method is very viscous, wax-like material with an aroma that is lighter, more delicate and more ethereal than the more typical Jasmine absolute.
Subcritical Fluid Extraction
Researchers developed a new method of coaxing volatile jasmine oil from the delicate flowers in an effort to find a more efficient manner of creating jasmine tea. In this process, activated carbon, a highly absorbent material, is placed in a closed chamber with jasmine flower petals while oxygen is pumped through. Once the activated carbon has taken in as much of the aromatic material as possible, the carbon is removed and placed in another chamber to which a solvent (in this case, dimethyl ether) is added at a specific, low temperature. After the solvent is vacuum distilled, the aromatic substances are all that remain.
Compared to CO2 supercritical extraction, this method is said to produce a jasmine oil that has less of the sweet notes that are typically produced when extracting at a higher temperature. Gas chromatography/mass spectroscopy analysis reveals that a sample of jasmine oil obtained from this method, compared to solvent extraction, contains significantly more of the chemicals that are thought to be largely behind jasmine’s alluring aroma: benzyl acetate (37.93% vs. 6.21%, respectively) and linalool (31.14% vs. 16.91%, respectively). Overall oil yields were also higher, with subcritical fluid extraction providing nearly 200 mg/kg more oil. In sum, the authors claim that this method is superior to conventional organic solvent extraction in that it provides lower operating temperatures and pressures, shorter extraction times, environmental compatibility, good selectivity, only one step for all separation, and little residual solvent formation.” (Ye, Q., Jin, X., Zhu, X., Lin, T., Hao, Z., Yang, Q. (2015). An Efficient Extraction Method for Fragrant Volatiles from Jasminum sambac (L.) Ait. J Oleo Sci. Apr 20. [Epub ahead of print])
Infused Jasmine Oil
A vegetable-infused jasmine oil can be made in which jasmine flower petals are infused or macerated in a vegetable oil such as palm oil or other vegetable oil. While this method is not typically utilized in commercial settings, it is a very simple way to create an infused jasmine oil at home if one has access to enough jasmine petals.
Another way to create a fragrant oil from jasmine flower petals, is the extraction method of enfleurage, or fat maceration, that was perfected hundreds of years ago in southern France, (Arctander, S. (1960) Perfume and Flavor Materials of Natural Origin. Artander) although it is believed the ancient pharaohs of Egypt also used this method to release the aromas from delicate flowers like jasmine and rose.
The traditional version of enfleurage is a two-step extraction process similar to an absolute that employs odorless animal fats, typically from cows or pigs. Fat is used as the lipophilic properties of fats excellently promote the extraction of the fragrance molecules from the flower petals. (Paibon, W., Yimnoi, C. A., Tembab, N., Boonlue, W., Jampachaisri, K., Nuengchamnong, N., et. al. (2011). Comparison and evaluation of volatile oils from three different extraction methods for some Thai fragrant flowers. J Cosmet Sci. 33(2): 150-6. doi: 10.1111/j.1468-2494.2010.00603.x.) The fat is spread across a glass plate housed inside a wooden frame, or châssis, and fresh, fully opened jasmine flower petals are carefully placed into the fat which is capable of readily dissolving the aromatic molecules present in the delicate flower petal and absorbing the fragrance. After a day or two, the spent flower petals are exchanged for fresh petals until the fat is completely saturated with the fragrant oil from the jasmine flower. The result of the first step is referred to as a pomade, rather than the concrete that would be produced by chemical extraction.
In order to release the jasmine oil from the pomade, alcohol is used as a dissolving agent in the second step. The aromatic molecules gravitate toward the alcohol, which is subsequently evaporated, leaving behind what is technically referred to as a ‘jasmine absolute by enfleurage.’ The chemical composition of an enfleurage typically resembles that of jasmine absolute, and contains benzyl acetate, ∂ - linalool, linalyl acetate, benzyl alcohol, jasmine, indole, methyl anthranilate, 3-hexen-1-ol, 3-hexen-1-ol acetate, methyl benzoate, phenyl actonitrile, benzyl ester, phenyl ethyl acetate, faranesene, cadinene, cis-3-hexenyl benzoate, benzyl benzoate, ferenesol or nerolidol.
An additional source of oil obtained from the enfleurage process is termed ‘jasmine absolute by châssis.’ In this extract, an absolute is obtained by solvent extracting the small amount of fat that remains on the spent flowers that are removed from the châssis, as well as the exhausted flowers. This fat is similarly alcohol extracted, chilled, filtered, and vacuum distilled to reach its end result: an absolute. The oil produced by this method is much darker than is typical of a jasmine absolute, nearly brown in color. It also has a much different scent profile, as this version of absolute contains less of the indole molecules typically present. The scent has been described as rich, fatty, and tenacious. (Arctander, S. (1960) Perfume and Flavor Materials of Natural Origin. Artander).
A more recent variation of the enfleurage process involves using cold vegetable fats (typically palm oil) rather than animal fats. The resulting oil is extracted using alcohol and then vacuum distilled, producing a truer, less fatty smelling jasmine. (source). This contemporary enfleurage process is not commonly used, and currently can only be found in Colombia, South America.
Both versions of the enfleurage process (animal or vegetable fat) can be executed in such a way that they can be certified ‘organic jasmine absolute by enfleurage.’ Similarly to organic extracts, the jasmine plants must be grown in an entirely organic matter. These organically grown petals are then pressed into an organic vegetable oil, and the resulting pomade is then dissolved using organic alcohol, typically sugar cane. Organic jasmine enfleurage is currently very expensive, as going rates typically amount to more than $500 per ounce of oil.
In yet another version of enfleurage, the Indian version uses hulled sesame seeds in place of the fat, which is laid down in a cement pit with jasmine flower petals (typically Jasminum sambac). After soaking in as much of the aromatic material as possible, the seeds are then run through a mill until the oil is completely extracted. Using this method, it takes nearly 1300 pounds of jasmine flowers to saturate 500 pounds of seeds. The resulting oil is termed ‘Sira’ oil, meaning it is of high quality. The flowers that were used during the first enfleurage processing can be used again to create baju (middle) or raji (low) grade oil. Oils produced from the Indian version of enfleurage are commonly used in body applications, as the method does not use heat in its application to break down the aromatic cell barriers and creates a more ‘pure’ product.
The appeal of enfleurage is that the use of no heat or low-heat temperatures, depending on the exact method, serves to preserve the aroma without damaging the delicate flower petals and destroying the chemical bonds that contain the pungent aroma. Also, the ‘chemical’ smell that can sometimes be present when extracting jasmine oil using chemical solvents is not present, leaving a truer fragrance behind that is quite similar in makeup to the flower itself. It has also been suggested that part of the reason a more accurate fragrance emulates from enfleurage is that the flower petals remain in their natural state during the few days they are placed on the fat; in a sense, they continue to live and give off their precious scent for those few days, rather than being immediately decimated by a chemical solvent. (Arctander, S. (1960) Perfume and Flavor Materials of Natural Origin. Artander). In this way, enfleurage brings out a more evolved, complete version of the aroma profile, rather than chemical extraction which removes the fragrance from the flower petals as they are at that exact moment.
One study found that in comparison to oil extracted from hydrodistillation and solvent extraction, research participants found enfleurage to have the truest scent when compared to actual jasmine flower petals. (Paibon, W., Yimnoi, C. A., Tembab, N., Boonlue, W., Jampachaisri, K., Nuengchamnong, N., et. al. (2011). Comparison and evaluation of volatile oils from three different extraction methods for some Thai fragrant flowers. J Cosmet Sci. 33(2): 150-6. doi: 10.1111/j.1468-2494.2010.00603.x.)
Enfleurage is not routinely employed anymore by commercial producers, especially outside of France, as the process of extracting jasmine as an absolute has become more popular. Largely, this is due to the fact that the process of enfleurage is quite a labor intensive and thus expensive, requiring a good deal of time and effort in order to coax the jasmine oil from the large amounts of flower material needed. Some estimates reveal that it can take weeks before the fat is completely saturated with the precious jasmine oil. Prices for one ounce of enfleurage can cost upwards of $300 and is increasingly difficult to find.
The method of distilling jasmine oil via attar is an ancient technique that has been used long before the two-step solvent extraction process. This method has been traditionally employed in India, specifically in a city named Kannauj in the northern part of the country.
This method typically involves hydro-, or water-distilling, the aromatic plant materials into a receiving vessel filled with either pure sandalwood oil (traditional) or vetiver oil (contemporary). This method most often uses Jasminum sambac flower petals to produce the attar, termed either ‘Bela’ or ‘Mogra’ attar. The flowers for the attars are harvested in the early evening and hydro-distilled in the late evening. Baskets full of Jasminum sambac petals are placed inside the copper still and covered with water. The aromatic molecules are steam distilled where they pass into a chamber containing sandalwood oil to create a hydrosol. This continues for a number of hours. After the resulting hydrosol is left to cool, the water separates from the sandalwood/jasmine mixture. The water is reused to distill another batch of attar, and this process continues on for approximately 15 more days.
At the completion of the hydro-distillation process, the remaining sandalwood/jasmine mixture only contains trace amounts of jasmine oil, typically thought to be approximately 3-5% of the aroma dissolved in the sandalwood oil. What remains is a very subtle jasmine note blended in a luscious sandalwood oil. Understandably, the resulting attar produces a very different scent profile than that of absolutes.
There is some debate as to whether jasmine ‘ruh,’ an oil created by a process refined in India, can be considered a true essential oil. Rather, it may be considered by many, in particular by French distilleries, to be classified as a ‘compounded oil’. The process of creating ruh is very similar to hydro-distillation and making an attar, in that the flower petals are placed into a copper deg vessel and the petals are steamed at a low temperature and pressure over a longer period of time than is customary. Jasmine ‘ruh’ can be created from multiple species of jasmine, including Jasminum grandiflorum (ruh chameli), jasmine auriculatum (ruh juhi), and Jasminum sambac (ruh motia).
However, the process differs from both an attar and a traditional absolute in many ways, as described by one company who produces ruhs:
“The main difference between a ruh and an attar is that in distilling the ruh the receiving vessel contains no sandalwood. In short, it is a pure essential [oil] distilled from the flower under low pressure and low temperature as compared with modern techniques. The yield is less than half of what can be expected if the same flower was subjected to extraction with solvents to produce a concrete and then washed with alcohol to produce the absolute. The cost is significantly higher than the absolute. The odor profile is also different as the distillation process captures more of the top notes than the absolute and less of the base notes.”
Comparison of Extraction Methods
One novel study sought to examine the differences in fragrance, yield, and chemical composition when extracting Jasminum sambac oil taken via three different methods: hydrodistillation, solvent extraction, and enfleurage. (Paibon, W., Yimnoi, C. A., Tembab, N., Boonlue, W., Jampachaisri, K., Nuengchamnong, N., et. al. (2011). Comparison and evaluation of volatile oils from three different extraction methods for some Thai fragrant flowers. J Cosmet Sci. 33(2): 150-6. doi: 10.1111/j.1468-2494.2010.00603.x.)
According to the study, jasmine oil extracted by solvent extraction produced the highest yield of fragrance oil. The lowest yield (.04%) was produced by the oil generated from hydrodistillation. The authors hypothesize that this is due to a large fraction of the fragrant molecules being lost to the atmosphere or being destroyed by the heat and/or water. Accordingly, when comparing the scents of the three oils extracted by different means to actual jasmine flower petals, research participants found this oil to smell the most dissimilar. The authors postulate that this is also due to the evaporation of the phytochemicals.
Jasmine oil obtained by enfleurage, on the other hand, had a reasonable yield of 37%. It also had the truest scent when compared to jasmine flower petals, as 39% of research participants confused oil obtained by enfleurage with actual jasmine flower petals.