Every perfume is a race between molecules evaporating at different speeds. Citrus and green notes leave first, florals and spices in the middle hours, and what remains on the skin at the end of the day is the base: woods, musks and, in a great many fragrances, resins. Resins are the perfumer’s way of making time pass more slowly.
Why resins are base notes
Resin molecules are big. Coniferyl benzoate, cinnamyl cinnamate, labdane diterpenes and the triterpenes of frankincense have high molecular weights and low vapour pressures; they sit on skin for hours or days. Two consequences follow. They are heard last, so they define the drydown. And they slow everything else: in a mixture, a heavy, slightly sticky base traps lighter molecules and lets them out gradually. That second effect is fixation, and it is why a citrus cologne with a touch of benzoin lasts longer than one without.
How resins are turned into perfume materials
Raw resin cannot go into a bottle. It is extracted:
- Resinoid. Raw resin washed with a solvent (hexane, ethanol, or a heavy solvent like benzyl benzoate), then the solvent removed. Dark, thick, sticky; close to the smell of the raw material; cheap. Used in soap, incense pastes, heavier bases.
- Absolute. The resinoid taken up in ethanol, chilled to drop out waxes, filtered, and the alcohol evaporated. Paler, cleaner, more diffusive, more expensive. The perfumery standard for benzoin, labdanum, opoponax, tolu, styrax.
- Essential oil. Steam distillation of the resin. Works for gum resins and oleoresins with a real volatile fraction (frankincense, myrrh, elemi, galbanum) and gives a lighter, fresher material. Does not work for benzoin, labdanum or the balsams, which have too little volatile oil.
- Tincture. Raw resin in alcohol, the oldest method and still useful for hobbyists and for softer, more natural-smelling bases.
See Benzoin absolute vs resinoid for the practical differences.
What each resin contributes
| Resin | Role in the base | Pairs with |
|---|---|---|
| Benzoin | Sweet, vanillic, powdery softener and fixative | Vanilla, labdanum, tonka, rose, sandalwood |
| Labdanum | Leathery, ambery, animalic warmth | Benzoin, vanilla, oakmoss, patchouli, Ambrox |
| Frankincense | Bright, resinous, smoky lift | Citrus, pepper, iris, cedar, myrrh |
| Myrrh | Bitter, dry, medicinal depth | Frankincense, rose, labdanum, saffron |
| Opoponax | Honeyed, balsamic bridge | Benzoin, labdanum, lavender, vanilla |
| Styrax | Leathery, spicy-floral darkness | Rose, iris, leather bases, labdanum |
| Tolu / Peru | Cinnamon-vanilla richness | Benzoin, vanilla, spices, tobacco |
| Elemi | Fresh lemon-pepper top over resin | Frankincense, cardamom, lavender, cedar |
| Galbanum | Sharp green opening | Iris, hyacinth, violet leaf, oakmoss |
The fragrance families that depend on them
Amber (oriental). Built on the labdanum–benzoin–vanilla accord, with styrax, tolu and opoponax for depth. See The ambery fragrance family.
Chypre. Oakmoss and labdanum over bergamot, with benzoin and styrax common in the base.
Fougère. Lavender, coumarin, oakmoss, with benzoin or tolu for warmth.
Incense and “sacred” perfumes. Frankincense and myrrh in the heart, benzoin and labdanum underneath.
Gourmand. Benzoin, tolu and vanilla for the edible sweetness, often with synthetic vanillin and ethyl maltol.
Regulation
The International Fragrance Association limits several resin materials because of sensitizing constituents: benzoin (benzyl benzoate, cinnamates), styrax and Peru balsam (cinnamates; crude Peru balsam is prohibited), tolu, opoponax. Limits depend on product category and change with each amendment. Anyone selling a product should formulate to the current standard. See Benzoin safety and allergies.
Getting started
Buy small amounts of benzoin absolute, labdanum absolute and a frankincense oil. Dilute each to 10 % in ethanol. Smell them on blotters over a day. Then combine labdanum and benzoin in different ratios and add a drop of vanilla: you will have understood the amber accord, and most of what resins do. See How to build an amber accord.
Frequently asked questions
What is a fixative in perfume?
A material that slows the evaporation of the more volatile components and holds the composition together on skin. Resins are natural fixatives because their large, heavy molecules evaporate slowly and interact with lighter ones.
What is the difference between a resinoid and an absolute?
A resinoid is made by washing raw resin with a solvent and evaporating it: thick, dark, close to the raw material. An absolute is a resinoid further purified with ethanol and filtered: cleaner, paler, more concentrated, more expensive.
Which resins are used most in perfumery?
Benzoin, labdanum, frankincense (olibanum), myrrh, opoponax, styrax, tolu, Peru balsam, elemi and galbanum. Benzoin and labdanum are the workhorses of amber bases; frankincense and elemi are the fresher, more top-to-heart resins.
Sources & further reading
- perfumery
- base notes
- fixatives
- resins
- pillar
