Over time, artisans and manufacturing industries have developed diverse manufacturing processes to extract the best odorous substances from plants, depending on their physical state. Each process produces different olfactory results, allowing the creator to expand his collection of components .
Enfleurage
The petals are placed on a glass plate, called a frame, covered with grease which absorbs their odor.
The process is repeated about 30 times to obtain a scented ointment. The ointment is scraped from the frame and washed in alcohol, obtaining a scented oil that is filtered, creating the "absolute" from which the perfume will be refined.
In hot enfleurage the petals are thrown into the melted fat in a bain-marie and stirred for two hours.
After about ten days, during which the flowers are renewed every day, the saturated fat is filtered using the same process as cold enfleurage.
In both cases, the perfumed alcohol thus obtained is called “pure absolute in ointment”.
Infusion
This is a particularly suitable process for slowly maturing raw materials of plant origin, such as vanilla pods, orris rhizome, tonka beans, and of animal origin, such as civet, musk, amber, and castoreum.
The substance is macerated in ethanol at varying concentrations, and then filtered. If the process is done hot, it's called infusion; if done cold, it's called tincture.
Squeezing
Squeezing is an extraction technique used for citrus peels, which uses mechanical actions such as scraping, pressing, centrifugation, etc.
The oil glands in the peel are compressed by a press or opened with rasps, and the released oil is drawn in by a current of water and then separated by centrifugation. More recently, pressing is done using a hydraulic press, where the citrus fruits are chopped and their pulp is steam distilled.
Steam distillation
Distillation is a very ancient technique, probably of Mesopotamian origin, which has been Developed by the Egyptians and perfected in the Middle Ages by the Arabs, it exploits the principle that most of the odorous molecules contained in a flower, a resin, or a bunch of grapes can be transported by vapor.
In a boiler (alembic), the substances to be distilled are mixed with a quantity of water equal to five times their weight. The water is brought to a boil, and the steam passes through the odorous substances and becomes charged with essential oils. This "odorous steam," conveyed through a swan neck to a cooler (a long coil immersed in a container of cold water), condenses and drips into a decantation vessel. Due to the difference in density, the essential oil is separated from the water (which remains fragrant and can be used) and collected. The resulting oil is light and moderately volatile.
Molecular distillation
Common transformation processes typically produce absolutes or essential oils, whose odor reflects part of the transformations they have undergone and does not always faithfully replicate that of the plant in its natural habitat. Thanks to the use of vacuum with a reduced steam circuit and low temperatures, molecular distillation allows the treatment of high-boiling-point products without damaging their odor.
During this process, the colored materials are not distilled, achieving the necessary separation and allowing the creation of colorless and therefore more versatile products for current perfumery uses and to respond to the public's demand for increasingly authentic products.
Fractionation
A technological extension of distillation, fractionation is an increasingly popular technique. It allows the various fractions of an essential oil to be isolated and the less desirable components to retain only the most noble components and obtain raw materials of the highest quality and finesse. Processes such as deterpenation (removal of terpenes) and rectification (separation of resins) make essences more stable and shelf-stable.
Extraction with volatile solvents
The process was first presented at the International Exhibition in Vienna in 1873 and has since then been applied to both dried and fresh raw materials.
In a special container, called an extractor, the natural material is repeatedly washed with a volatile solvent (for example, hexane), which has a high solubilizing power and is easily eliminated by evaporation. By following pre-established times, the olfactory principle, waxes, and pigments are obtained. After repeated passages in the decantation vessel, the scented and colored concentrate , more or less solid ( concrete ), is finally collected on one side, and the solvent on the other, which will be recovered and reused.
If the treated raw material is a balm, gum, or resin, a resinoid is obtained, which can be used in this same form by perfumers. Concretes, on the other hand, undergo another treatment, extraction with alcohol, to obtain a purer product, the absolute. The treated concentrate is then filtered, frozen, and filtered again to separate the insoluble waxy residues. Finally, it is concentrated under vacuum to eliminate all traces of alcohol.
Extraction by CO2 or super critical
It's a gentle extraction method because it allows for the extraction of low-volatile odorants, such as those released by spices and, in general, dried raw materials. Furthermore, there are no thermal alterations to the odor, no traces of solvents, and the resulting materials have extremely pure odors.
It is a process inspired by extraction with volatile solvents: carbon dioxide, converted to liquid form under pressure (supercritical state) and at low temperature, replaces hexane or other solvents. The resulting extract can resemble a resinoid which, when washed with alcohol, is then transformed into an absolute .
New production processes
Traditional extraction methods give rise to numerous derivatives, improved with the support of technology.
Furthermore, evolving consumer tastes toward increasingly authentic scents, the search for increasingly exclusive and unusual odors, and society's growing ecological awareness, attentive to protecting resources and endangered species, have pushed manufacturing industries to develop increasingly refined technologies and establish eco-conscious collaborations.
There are substances that release wonderful odors that no extraction method can capture. Fruit is an example, as are sweet treats. Some plants are not suited to extensive cultivation. Nature already provides many resources but is unable to renew itself at the speed at which needs emerge.
To tap into new riches without damaging the delicate ecological balance, leading companies in the sector have developed new production processes.
In the 1970s, the first cutting-edge technology was identified: Head Space. This technique involves enclosing flowers or plants, too delicate to be treated with traditional extraction processes, in a container containing a microreceptor with mild absorbency. The scented air around the flower is absorbed by the microreceptor for a period of time ranging from half an hour to several hours, depending on the species. The fragrance absorbed from the air surrounding the flower can be recovered through extraction using a suitable solvent. The different odorant molecules in the resulting sample are separated from one another, and those that will most faithfully reproduce the flower's scent are then selected. Once this selection is made, all the molecules must be harmonized to achieve a result as faithful to nature as possible.