Perfumery naturals are named by the process that made them, not only by the plant. The same jasmine flower can become a concrete, an absolute or a floral wax, and each smells and behaves differently. The definitions below follow ISO 9235, the international vocabulary for aromatic natural raw materials.
Essential oil
An essential oil is obtained by distillation with water or steam, by dry distillation, or — for citrus fruits — by mechanical expression of the peel. It contains only the volatile part of the plant. Distillation suits robust materials such as roots, woods, leaves and seeds: vetiver, patchouli, cedarwood and cardamom are all essential oils.
Concrete
A concrete is an extract obtained from fresh plant material by extraction with a non-aqueous solvent, which is then removed. Because the solvent dissolves waxes and pigments as well as odorants, a concrete is usually waxy and semi-solid at room temperature. Flowers too delicate for a still, such as jasmine and tuberose, are extracted this way. Concretes are used where their waxes are welcome — in solid perfumes and some oil-based products — and as the starting point for absolutes.
Absolute
An absolute is made from a concrete (or a resinoid) by extraction with ethanol. The alcoholic solution is chilled and filtered to drop out the waxes, and the ethanol is then removed. What remains is a concentrated, alcohol-soluble material that is the closest perfumery gets to the smell of the living flower — which is why jasmine, tuberose, orange flower and rose absolutes are the foundation of fine-fragrance florals.
Resinoid
A resinoid is extracted with a solvent from a non-cellular natural material — a resin, gum resin, balsam or oleoresin — rather than from fresh plant tissue. The result is thick, tenacious and slow to evaporate, which is why labdanum, benzoin, olibanum and styrax resinoids are used as fixatives and to give a base its warmth.
At a glance
| Starting material | Process | Texture | Typical use | |
|---|---|---|---|---|
| Essential oil | Roots, woods, leaves, seeds, peel | Distillation or expression | Liquid | All applications |
| Concrete | Fresh flowers and plant tissue | Solvent extraction | Waxy, semi-solid | Oil and solid perfumes; making absolutes |
| Absolute | A concrete or resinoid | Ethanol washing, chilling, filtering | Viscous liquid | Fine fragrance, alcohol-based perfume |
| Resinoid | Resins, gums, balsams | Solvent extraction | Thick, tenacious | Fixatives, ambers, orientals, incense |
Which one should you buy?
For alcohol-based fine fragrance, absolutes dissolve cleanly where concretes leave a waxy haze. For attars and oil-based perfumes, a concrete or an absolute will both work, and a concrete may be the more economical choice. For a long-lasting base, resinoids do the work of fixing. If you are unsure, ask for 30 g samples of each form and compare them in your own base — that is the only test that settles it.
Questions to ask a supplier
- Is this an absolute, or a “base” or “type” built to resemble one? Both are legitimate; they are not the same thing, and should not cost the same.
- Which solvent was used, and what does the specification say about residues?
- What is the botanical name and origin, and does the COA match the lot you receive?
- What does the IFRA conformity certificate allow in your product category?