Natural perfume materials are obtained through a handful of main processes: distillation, cold expression for citrus fruits, extraction with volatile solvents and, more recently, supercritical CO2 extraction. Each process captures only part of the plant's molecules. The same rose, iris or vanilla can therefore yield materials that do not smell alike. Alongside these natural extracts, perfumers work with isolated molecules and synthetic molecules.
Steam distillation and hydrodistillation
Distillation is the oldest and most widespread process. In steam distillation, the plant material sits on a grid inside a still. Steam passes through it and carries off the most volatile odorous molecules. The mixture then travels through a cooled coil, where it condenses. At the outlet, the essential oil, lighter than water and barely soluble in it, separates and floats on the surface. The water left behind keeps part of the scent: this is the floral water, or hydrosol, such as rose water or orange blossom water.
In hydrodistillation, the plant is immersed directly in water, which is brought to the boil. This method suits materials that clump together or do not stand up well to dry steam. Damask rose is traditionally distilled this way in Bulgaria and Turkey. So is agarwood, often over several days, as we explain in our article on oud.
Yields vary enormously. Sandalwood gives a few percent of its weight in oil, clove buds even more. Rose gives a tiny fraction: several tons of petals are needed for one kilo of essential oil. That is one of the reasons for its price.
Distillation has its limits. Heat and water damage certain molecules, and many delicate flowers give very little oil, or an oil that does not resemble them. Jasmine and tuberose, for example, are hardly ever distilled. Other processes take over.
Dry distillation uses no water. Birch or cade juniper wood is heated without air until it releases a thick tar. Once rectified, these tars bring the smoky, leathery notes found in many perfumes.
Cold expression of citrus fruits
Citrus fruits are handled separately. Their oil sits in small pockets visible on the surface of the peel. Breaking them is enough to release it, with no heat at all. In Sicily and Calabria, the fruit used to be rubbed by hand against vessels lined with spikes, and the oil was then collected with a sponge. Today, machines grate or press the peels, and the oil is separated from the water by centrifugation.
The result is called an essence rather than an essential oil, since it is not distilled. It keeps a brightness and a zesty quality that distillation tends to dull. Bergamot, lemon, orange, mandarin, grapefruit and yuzu are almost always cold expressed.
These essences contain furocoumarins, molecules that make the skin sensitive to sunlight. Bergamot is rich in them. Perfumery therefore often uses a bergamot treated to remove them, known as "furocoumarin free".
Volatile solvents: concrete, absolute and resinoids
For flowers that do not take well to distillation, volatile solvents are used. The process developed at the end of the 19th century. The flowers are washed in a solvent, today most often hexane, which dissolves their odorous molecules but also their waxes and pigments. The solvent is then evaporated and recovered. What remains is a solid, waxy paste: the concrete.
Because of its waxes, the concrete does not dissolve in perfume alcohol. It is therefore washed with alcohol, the mixture is chilled so the waxes set, then filtered, and the alcohol is evaporated. The result is the absolute, a thick, concentrated and often colored liquid. It is the form closest to the smell of the fresh flower, with a depth and a honeyed side that distilled oil lacks.
Jasmine, tuberose, orange blossom, mimosa and centifolia rose from Grasse and Morocco are mostly worked as absolutes. The process is also used for materials that are not flowers: violet leaves, blackcurrant buds, tonka bean, vanilla pods, coffee, cocoa or tobacco leaves.
Resins and balsams, which are already dry, follow a similar path. Benzoin, labdanum, olibanum and myrrh are treated with a solvent, often alcohol. The result is a resinoid, a dense, sticky material used as a fixative in amber and balsamic bases.
Enfleurage, a technique from history
Before solvents, Grasse perfumery processed the most delicate flowers by enfleurage. Glass frames were coated with a purified, odorless animal fat. Workers laid the fresh flowers on it one by one, then replaced them every day for weeks, until the fat was saturated with scent. This perfumed fat was called the pomade. It was then washed with alcohol to draw out the fragrance.
Enfleurage required a huge amount of labor for very little material. It was abandoned during the 20th century and replaced by solvent extraction. Only a few artisans still practice it.
Supercritical CO2 extraction
Carbon dioxide becomes an effective solvent when it is compressed and gently heated. Above about 31 °C and under high pressure, it enters a so-called supercritical state, between gas and liquid. It then passes through the plant material and dissolves its odorous molecules. When the pressure is released, the CO2 turns back into gas and escapes, leaving no residue.
The process works at low temperature. It preserves molecules that the heat of distillation damages and recovers heavier compounds that steam does not carry. A CO2 extract often smells more faithfully of the raw material: crushed pink peppercorn, fresh ginger, the vanilla pod itself. It spread through perfumery at the end of the 20th century, especially for spices, seeds, woods and certain resins.
On a product page, the word "CO2" or "CO₂" after the name of a material indicates this process.
Tinctures and infusions
A tincture is the simplest method: the material is left to macerate in alcohol for weeks or months, then filtered. The alcohol slowly takes on the scent. Perfumers of the past prepared their tinctures of vanilla, benzoin, tonka bean, ambergris or musk this way.
Musk and civet tinctures have disappeared from mainstream perfumery. Ambergris tincture still exists, because this material, expelled by the sperm whale, is gathered on beaches without harming the animal. A tincture gives a softer, more diffuse result than an absolute. Some independent perfumers still prepare their own tinctures and infusions.
Fractionating, rectifying, isolating
An essential oil is not always used exactly as it comes out of the still. It can be redistilled under vacuum to separate its fractions, the lightest on one side, the heaviest on the other. This is fractionation, or rectification. It serves to remove an unwanted facet: the earthy, camphoraceous side of a patchouli, the dark color of an oil, allergenic molecules restricted by regulation.
Molecular distillation goes further. It works under a very deep vacuum, at moderate temperature, over a very short distance. It produces clearer qualities, such as the so-called "heart" patchoulis, woodier and less earthy.
The last step is the isolate: a single molecule extracted from a natural material. Linalool is drawn from Ho wood, eugenol from clove, citral from litsea cubeba, menthol from mint. An isolate is natural in origin, but it carries only one note of the plant.
Headspace: capturing the scent of a living flower
Some flowers give no usable extract at all. Lily of the valley, lilac, freesia and peony have never been extracted profitably. To reproduce them, chemists developed headspace capture in the 1970s and 1980s, notably Roman Kaiser at Givaudan.
A glass bell is placed around a flower still on its stem, and the surrounding air is drawn through a trap that holds the odorous molecules. Laboratory analysis then reveals the exact composition of this living scent. The flower remains intact. The perfumer then rebuilds its smell with available molecules, natural or synthetic. Headspace is a way of understanding a scent and provides no raw material. It is also used to study the smell of a forest, a rare plant or a fruit.
The role of synthetic molecules
Since the end of the 19th century, chemistry has supplied molecules that do not need to be extracted. Coumarin, synthesized as early as 1868, smells of hay and almond. Vanillin reproduces the main scent of vanilla, as we explain in our article on vanilla. Other molecules imitate materials that have become rare or protected, such as Mysore sandalwood, covered in our article on sandalwood, ambergris or animal musk. Ambroxan, made from a molecule found in clary sage, recalls ambergris.
Some molecules imitate nothing at all. ISO E Super, a molecule created in the 1970s, has a woody, velvety, almost abstract smell.
Synthesis plays several roles. It makes possible smells that do not exist in nature, stabilizes formulas, lowers costs and avoids harvesting endangered species. Almost every perfume combines natural extracts and synthetic molecules.
Why the same material smells different depending on the process
Each process acts as a filter. Distillation keeps the molecules that are volatile and can withstand heat. Solvents also take the heavy molecules. CO2 captures both light and heavy molecules, without heating them. The same plant therefore gives several materials.
Rose is the clearest example. Rose otto, the distilled oil of Damask rose, smells fresh, lemony, slightly green and peppery. Rose absolute smells rounder, more honeyed, closer to the petal. The reason is well known: phenylethyl alcohol, a molecule with a soft rose scent, dissolves in water. During distillation, most of it stays in the rose water. The absolute keeps it.
Iris shows another case. The scent comes not from the flower but from the rhizome of Iris pallida, which is dried for several years. During this aging, irones form, the molecules behind the powdery, violet scent of iris. The rhizome is then ground and steam distilled. The resulting oil sets at room temperature because of the fatty acids it contains: it is called orris butter or iris concrete. Here the word describes its texture, not a concrete in the solvent sense. Freed of these fatty acids, it gives orris absolute, which is more concentrated. It is one of the most expensive materials in perfumery.
The bitter orange tree alone gives several materials. Its distilled flowers give neroli, fresh and green, and orange blossom water. The same flowers extracted with solvent give orange blossom absolute, headier and more animalic. Its distilled leaves and young twigs give petitgrain, and the pressed peel of its fruit gives bitter orange essence.
Vanilla, finally, comes as an absolute, dark, woody and tobacco-like, or as a CO2 extract, truer to the pod and more gourmand. A product page that specifies the process therefore points to a choice made by the perfumer, just like the origin of the material.
Perfumes that name their processes
Most pyramids list a note without saying in what form it is used. The perfumes below are exceptions: their product pages explicitly name an oil, an absolute, a CO2 extract, a tincture or a molecule. These mentions tell you about some of the materials in the formula, without giving its full composition.
Rose otto and iris concrete
Oborotsuki, by Tada Parfumeur, brings together two of the materials described above. Thai oud, camphor and incense in the top, then jatamansi, rose otto and vetiver in the heart, over a base of Australian sandalwood, patchouli, oakmoss and iris concrete. The product page presents it as a 100% natural perfume, green, woody and earthy. The rose appears here in its distilled form, fresher than the absolute. The perfume has been discontinued by the house, and the bottles in stock are the last ones. Our profile of Tada Parfumeur tells more about the perfumer.
Citrus essences and orange blossom
Iyokan, from the same house, details almost every material. Iyokan oil, bergamot oil, pear and neroli oil in the top, then yuzu oil, jasmine, lily of the valley and orange blossom absolute in the heart, over a woody, amber base. Iyokan is a Japanese citrus fruit. The perfume pairs neroli and orange blossom absolute, two materials drawn from the same flower by two different processes.
A distilled wood oil
Sugidama, also by Tada Parfumeur, opens on sugi oil, Japanese cedar, with lavender, bergamot and saffron. A sugidama is the ball of sugi branches hung at the entrance of sake breweries, and the perfumer says he brought back wood used for the casks.
Absolutes of flowers and leaves
Lamoon, by Tada Parfumeur, lines up four absolutes: orange blossom and pandan in the top, jasmine sambac in the heart, ambrette seed in the base, with a coconut cream accord and vanilla. Jasmine and orange blossom are two flowers typically worked with solvents. Pandan is a leaf used in Southeast Asian desserts.
Red Fever, by Aaron Terence Hughes, puts a number on its rose. According to the product page, it contains 4% rose absolute, spread between the heart, with lily, raspberry, plum and peach, and the base, with almond, vanilla, amber, oakmoss and ambergris. The absolute gives a round, jammy rose here. Our profile of Aaron Terence Hughes tells more about the house.
Mango Ambrosia, by Zhufu, uses a less common absolute, green mango leaf, in the top with Calabrian bergamot, finger lime, pomelo and saffron. The heart adds an orange blossom absolute from Grasse to mango and tuberose. See our article on Zhufu.
Cocoa and tobacco absolutes
Virtues, by Cæleste, places a cocoa absolute in the heart, with jasmine, iris and honey, after a top of bergamot, star anise, cinnamon and clove. The very resinous base includes Mysore sandalwood, incense, benzoin, vanilla and labdanum. Our article on Cæleste introduces the house.
Adiere, by Adi ale Van, uses two absolutes. Tobacco absolute in the heart, with a whisky accord, leather, an ink accord and pine wood. Vanilla absolute in the base, with a smoke accord, patchouli, tonka, amber, cocoa and oud. See our profile of Adi ale Van.
CO2 extracts
Aswan, by Widian, uses a pink pepper CO2 in the top, with bergamot and raspberry. The heart brings together violet leaves, Virginia cedar and ambergris, the base patchouli, vanilla, tobacco, musk and leather. The CO2 extract renders the fresh, resinous berry of pink pepper very well. Our article on Widian introduces the house.
Itim Kati, by Tada Parfumeur, combines three processes in a single pyramid: a tonka bean absolute in the heart, with jasmine, cotton candy and Siam benzoin, then a roasted coconut CO2 and a sandalwood oil in the base, with vanilla and woody notes. The perfume recalls a coconut ice cream sold in the streets of Thailand.
A vanilla tincture
Bourbon Vanilla, by Shaman Perfumery, is one of the few perfumes to mention a tincture. Its heart combines a Bourbon vanilla absolute and a Bourbon vanilla tincture, with labdanum and Peru balsam, between a top of saffron, anise and heliotrope and a base of sandalwood, cedar, guaiac and amber. It is currently out of stock. The house is introduced in our article on Shaman Perfumery.
Wood tars
Labels of Feelings, by Adi ale Van, composed by Antonio Alessandria, opens with a blackcurrant bud absolute and juniper tar, with passion fruit and plum. The heart is floral, and the base brings together cedar, olibanum, labdanum, leather and smoke. The product page describes a white floral set on a tarry, leathery base.
Kama, by Pernoire, opens on birch tar, with blackberry, violet and orris root. Cotton candy, leather, cypriol and dry amber form the heart, moss, cashmere wool and musk the base. Birch tar gives the smoky leather that the product page sets against the candy note. Our profile of Pernoire covers the Swiss house in detail.
Molecules named on the product page
Vitias, by Pernoire, lists ISO E Super in the base, with ambergris, white musk and marine notes. The heart brings together angelica root, iris, blond woods and guaiac. The molecule lends its woody, velvety effect to a marine perfume.
New York, by Widian, names Akigalawood in the heart, a woody, peppery material derived from patchouli, alongside geranium, iris, rose, jasmine, patchouli and caramel.
Other perfumes in the catalog play with these materials in our selections of floral perfumes, woody perfumes and fresh perfumes.
Frequently asked questions
What is the difference between an essential oil and an absolute?
An essential oil is obtained by steam or water distillation. An absolute is obtained with a solvent, then washed with alcohol. The oil is lighter and fresher. The absolute is thicker, more colored, and often closer to the smell of the fresh flower.
Are an essence and an essential oil the same thing?
In perfumery vocabulary, an essence is the oil of citrus fruits obtained by cold expression of the peel, without distillation. An essential oil is distilled. In everyday language, the two words are often used interchangeably.
Is there any solvent left in an absolute?
The solvent is evaporated after extraction, and residual traces are governed by regulation. This is one of the reasons for the interest in CO2 extraction, which leaves no residue since the gas escapes completely.
Is a 100% natural perfume better?
Not necessarily. A natural perfume often has a more vivid texture and evolves more on the skin. It also has a more limited palette, since some smells, such as lily of the valley, do not exist as natural extracts. Quality depends above all on the composition and the materials chosen.
Why is iris so expensive?
The rhizomes must dry for several years before being distilled, and the yield of orris butter is very low. Time, labor and the quantity of material required explain its price, one of the highest in perfumery.
Further reading
The materials mentioned here are presented one by one in our guide Perfume materials, with detailed articles on oud, sandalwood and vanilla. To learn how to read a pyramid and the olfactory families, see our page Understanding a perfume. To feel the difference between a rose otto and a rose absolute on your own skin, the perfumes mentioned are available as 2 ml samples depending on the house, on our samples page.