How Perfume Ingredients Are Extracted

Natural perfume ingredients are extracted in five main ways. Steam distillation carries aromatic molecules out of plants with steam and is used for most essential oils. Expression, or cold pressing, squeezes oil from citrus peel. Solvent extraction dissolves the scent of delicate flowers such as jasmine to make concretes and absolutes. CO2 extraction uses carbon dioxide under pressure to give extracts close to the raw material. Enfleurage, absorbing scent into fat, is historic and now rare. Each method suits different materials and gives a different smell from the same plant.

Steam distillation

Plant material — leaves, flowers, wood, roots, seeds — is exposed to steam. The heat releases aromatic molecules, which travel with the steam into a cooled condenser. There the vapour becomes liquid again, and the oil separates from the water and is collected. The fragrant water left behind is a hydrosol, such as rose water.

Used for: lavender, rose oil, vetiver, patchouli, sandalwood, cedar, geranium, many herbs and spices.

Distillation is old, robust and relatively simple, but heat can alter delicate materials, so some flowers lose much of their character this way.

Expression (cold pressing)

Citrus oils sit in tiny glands in the peel. Expression releases them mechanically — historically by hand-pressing peel against sponges, now by machines that scrape or press the fruit — without heat, which keeps their fresh, sparkling character.

Used for: bergamot, lemon, orange, mandarin, grapefruit. See Bergamot in Perfume.

Solvent extraction

For flowers too delicate to survive distillation, a solvent dissolves their aromatic molecules along with waxes and pigments. Removing the solvent leaves a waxy, fragrant mass called a concrete. Washing the concrete with alcohol and removing the waxes gives an absolute — intense, rich and close to the living flower.

Used for: jasmine, tuberose, rose absolute, orange blossom, mimosa. Resins and balsams are treated similarly to make resinoids, such as benzoin and labdanum. See Jasmine in Perfume and Rose in Perfume.

CO2 extraction

Carbon dioxide under pressure behaves as a solvent and, when the pressure is released, simply evaporates, leaving no residue. CO2 extracts often smell strikingly like the raw material — a vanilla CO2 smells of the pod, a pink pepper CO2 of crushed peppercorns. The equipment is costly, so the method is used for selected materials. See Vanilla in Perfume.

The same flower, distilled, pressed into fat or washed in solvent, gives three different smells. Extraction is the first act of interpretation.

Enfleurage

In the traditional method associated with Grasse, fresh petals were laid on glass plates coated with purified fat, which absorbed their scent; spent petals were replaced daily for weeks. The scented fat, or pomade, was then washed with alcohol. It was laborious and expensive, and has been almost entirely replaced by solvent extraction, though it survives as a craft demonstration and in small-scale artisanal work. See the story of Grasse.

Isolates

Some natural oils are further separated into individual molecules — isolates — such as linalool from certain oils. Isolates are natural in origin but used like single synthetic materials, giving perfumers a particular facet of a plant on its own.

Why the method matters

The same plant can smell different depending on how it is extracted. Rose oil from distillation is bright and lemony; rose absolute from solvent extraction is deep and honeyed. Perfumers choose between them for the effect they want — another reason a note on a perfume describes an impression rather than a single ingredient. See Are Perfume Notes Real Ingredients?.

Where synthetic materials come in

Synthetic aroma molecules are not extracted from plants but made by chemical processes, sometimes from natural starting materials. They complement naturals rather than simply replacing them. See How Synthetic Molecules Created Modern Perfume and Is Natural Perfume Better Than Synthetic?.

Common questions

What is the difference between an essential oil and an absolute?

An essential oil is usually distilled or pressed; an absolute is made by solvent extraction. Absolutes are generally richer and closer to the fresh flower.

Are there traces of solvent in absolutes?

Absolutes are processed to remove the solvent; regulations and industry standards limit residues.

Why don’t some flowers have an oil?

Some, such as lily of the valley, yield too little or nothing usable by any method, so their notes are built from other materials.