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How is fragrance extracted from flowers and plants?

By Omer Siton, founder of PerfuMate · Updated

By six methods, each suited to a different plant: distillation for most leaves, woods, seeds and many flowers; pressing for citrus peel; solvent extraction into concretes and absolutes for delicate flowers; supercritical CO2; tinctures in alcohol; and enfleurage in fat, which the trade has abandoned. The method changes the smell, which is why the same rose is sold as an otto, an absolute and a CO2 extract that smell different.

Which extraction methods are there, and what does each make?

Each method has its own product, and ISO 9235, the international vocabulary of aromatic natural raw materials, names them; the table pairs each with materials from PerfuMate's catalog.

MethodWhat it makesCatalog examples
Steam or water distillationEssential oil, plus an aromatic water (hydrolate)Rose Otto, Lavender Essential Oil, Vetiver Essential Oil, Orris Butter
Cold pressing (expression)Cold-pressed essential oilBergamot Essential Oil, Lemon Essential Oil
Solvent extractionA concrete (fresh material) or a resinoid (dried), then an absolute by washing with ethanolJasmine Grandiflorum Concrete and Absolute, Benzoin Siam resinoid
Supercritical CO2Supercritical fluid extractRose CO2 Extract, Vanilla CO2 Extract, Agarwood CO2 extract
Maceration in alcoholTinctureVanilla Tincture, Orris Root Tincture, Ambergris Tincture
EnfleurageA pomade (perfumed fat), then an absolute by washing with alcoholHistoric; nothing in the catalog is made this way

How are essential oils distilled?

Steam carries the volatile part of the plant out of the still, the vapour is cooled, and the oil that separates from the water is the essential oil; the water left behind is the hydrolate, such as lavender water or orange blossom water.

ISO 9235 counts two kinds of steam distillation: directly by steam, which passes through the plant, and hydrodistillation, with water added to the still so that plant and water are heated together. Rose is hydrodistilled, and its distillation water is distilled a second time (cohobation) to recover more oil; even so, the rose bulletin of the Botanical Adulterants Prevention Program puts the yield at about 4,000 kg of flowers per kilogram of oil. A small home still works the same way and mostly makes floral water: rose water, the bulletin notes, usually carries less than 0.1 percent of rose oil.

Distillation also changes the smell. Heat can break down delicate molecules, and molecules that dissolve well in water stay behind in it. Phenethyl alcohol, the honeyed body of a rose, is one: extracts of rose water carry much more of it than the oil does. That is why the catalog estimates Rose Otto at about 38 percent citronellol and 20 percent geraniol, while the solvent-extracted Rose Absolute is about 62 percent phenethyl alcohol: two roses from one flower. Ylang ylang shows another effect: it is distilled in fractions, and a 2026 review of ylang-ylang notes that the extra and first grades are collected in the first hours; the catalog describes the extra as the first, finest fraction and carries Ylang Ylang Essential Oil Extra, First, Second and III as separate materials.

What is expression (cold pressing), and why are pressed citrus oils phototoxic?

Expression squeezes the oil out of citrus peel mechanically at room temperature, and because nothing is distilled, the heavy furocoumarins in the peel come out with it; those molecules react with sunlight on skin, which is why IFRA caps the expressed oils.

ISO 9235 defines a cold-pressed essential oil as one obtained by mechanical processes from the peel of a citrus fruit, at ambient temperature. The US Cosmetic Ingredient Review's assessment of citrus peel oils puts the contrast in one line: steam distillation removes non-volatile furocoumarins. In IFRA's 51st Amendment, Category 4, the expressed oils are capped as a share of the finished perfume: bergamot 0.4 percent, lime 0.7, bitter orange 1.25, lemon 2 and grapefruit 4, with a separate limit of 0.0015 percent on the bergapten all of them bring together. Distilled and furocoumarin-free (FCF) grades are separate materials, not capped by those standards: Bergamot FCF Essential Oil, Lime Essential Oil Distilled, Lemon Essential Oil Distilled. They still carry citral, limonene and linalool. Phototoxic perfume ingredients has the full list.

What are concretes and absolutes (solvent extraction)?

A concrete is what a solvent such as hexane draws out of fresh flowers: scent, pigment and plant wax together, a waxy mass once the solvent is removed; washing the concrete with ethanol, chilling it and filtering out the wax, then distilling off the ethanol, gives the absolute.

That is ISO's definition, and the rose bulletin describes the same chain: rose concrete from soaking fresh petals in hexane or petroleum ether, rose absolute as the ethanol extract of the concrete. A dried raw material gives a resinoid instead, such as Benzoin Siam resinoid. Solvent extraction took over the delicate flowers, jasmine and tuberose above all, and it keeps molecules a still loses: the bulletin puts rose absolute's yield at about ten times the oil's, with phenethyl alcohol at about 60 percent of its volatiles.

The wax is why concretes suit solid perfumes and why absolutes can leave a faint haze in alcohol. The catalog describes Mimosa Concrete as carrying a high wax load, and Orange Flower Water Absolute as the absolute recovered from the water left over from neroli distillation, the water-soluble half of the flower. Why a perfume turns cloudy.

What is CO2 extraction?

CO2 extraction uses carbon dioxide under pressure as the solvent: above about 31 degrees Celsius and 74 bar it becomes a supercritical fluid that dissolves aromatic molecules, and when the pressure is released it turns back into gas and leaves the extract behind, with no solvent left in it.

The critical point is NIST's figure for carbon dioxide (304.2 K and 73.8 bar). Because the method works at a lower temperature, a 2025 study of agarwood oil notes, it keeps aroma molecules that heat would destroy; carbon dioxide itself, the 2026 ylang-ylang review adds, is non-toxic and non-flammable. The extracts smell different from both oil and absolute: the catalog describes Rose CO2 Extract as carrying the fresh green top the otto cooks off and the honeyed body the otto leaves behind, and Vanilla CO2 Extract as closer to the split bean than the absolute. The rose bulletin adds that rose CO2 extract comes at a low yield and differs in composition from the oil and the absolute.

What is enfleurage, and how does it work?

Enfleurage draws a flower's scent into fat: fresh petals are laid on a layer of odourless fat and replaced again and again until the fat is saturated, and the scented fat, a pomade, is washed with alcohol to give an absolute.

ISO 9235 distinguishes cold enfleurage, where the scent diffuses into fat at room temperature, from hot enfleurage, where the flowers are digested in melted fat. In the cold method, as the perfumery school Cinquième Sens describes it, fat was spread on a glass plate 50 to 60 cm across held in a wooden frame, the chassis; 30 to 50 g of sorted flowers were laid on it, and the operation was renewed 30 to 40 times. The saturated fat was beaten with alcohol, which takes up the scent, and evaporating the alcohol left the absolute of pomade. A 2021 review in Molecules describes the fat as lard or tallow and the flowers as the ones too sensitive to heat for a still, jasmine, tuberose and orange flower, and notes that enfleurage was abandoned for its cost and replaced by solvent extraction.

How long does enfleurage take? With 30 to 40 charges of flowers, each left on the fat for a day or a few, one batch takes weeks to months. At home it works on the same principle, with a glass dish and a fat that has no smell of its own; how to make perfume from flowers gives the steps and the hygiene that keeps mould out.

What is a tincture in perfumery, and how do you make one?

A tincture is a single raw material soaked in alcohol until the alcohol has taken up its scent: ISO 9235 defines it as a solution obtained by maceration of a natural raw material in ethanol of various strengths, or in water, with tincture of benzoin, tincture of ambergris and vanilla infusion as its examples.

A tincture is a material, not a perfume: one raw material in alcohol, weighed into a formula like any other line, where a perfume is a composed blend. The catalog carries several. Vanilla Tincture is cured beans macerated in perfumer's alcohol at 10 to 20 percent; Orris Root Tincture is estimated at about 90 percent ethanol; Ambergris Tincture is used at 1 to 5 percent tincture strength; and Deer Musk Tincture is, the catalog notes, replaced in modern work by synthetic musk reconstitutions.

  1. Weigh the raw material and the alcohol. For a 10 percent vanilla tincture: 10 g of chopped cured vanilla beans and 90 g of Perfumer's ethanol.
  2. Close it in a jar, keep it in the dark and shake it every few days.
  3. Smell a strip each week, and stop when it no longer gets stronger.
  4. Filter it, chill it for a day and filter again, then label it with the material, the strength, the solvent and the date, like any dilution.

In a formula a tincture adds little aromatic weight: the catalog estimates Vanilla Tincture at about 0.4 percent vanillin against about 20 percent in Vanilla absolute. So "how many drops of tincture" is the wrong question: weigh it, and count the alcohol it brings as solvent. How to label dilutions.

How is sandalwood oil, and a sandalwood perfume, made?

Sandalwood oil is steam-distilled from the heartwood of mature sandalwood trees; a sandalwood perfume is built from that oil, from synthetic sandalwood molecules, or from both.

A 2024 review in Biomolecules describes the oil as mainly extracted from the heartwood of well-matured trees by steam distillation, with santalols making up about 90 percent of its sesquiterpenes: 40 to 60 percent alpha-santalol and 20 to 25 percent beta-santalol. The catalog estimates Sandalwood Essential Oil East Indian at 50 and 20 percent. Supply is the difficulty: the same review cites 2004 records putting Indian sandalwood oil production at around 70 tonnes, down from nearly 180 to 200 tonnes in earlier decades. The catalog also lists Western Australian plantation Santalum album, which it calls the dominant legal supply of genuine album oil, the drier Australian sandalwood and New Caledonian sandalwood.

A sandalwood note can also be built from synthetic molecules: Sandalore, Javanol, Ebanol, Bacdanol and Polysantol. PerfuMate's Sandalwood Accord is built on them: Sandalore 22 percent, Iso E Super 18, Bacdanol 15, Ethylene Brassylate 14, Ebanol 12, with a lactone for the milky note of the real wood. Natural or not, it is checked like anything else: by its typical composition, the East Indian oil on its own would pass Category 4 up to about 30 percent of a perfume, where its farnesol reaches the limit, and Sandalore has a standard of its own. The EU allergen list names both the oil and santalol (Santalum Album Oil, Santalol). Sandalwood oil is also the base of traditional Indian attars: what attar is.

PerfuMate's catalog keeps the grades apart, otto from absolute, expressed from distilled, oil from CO2 extract, each with its own typical constituents, so the IFRA check reads the material you actually weighed. Start a formula, free.

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