Short answer
Natural fragrance materials differ by how they are extracted. Essential oils are distilled with steam or water, or expressed from citrus peel. Concretes are made by washing plant material with a volatile solvent, and absolutes by washing the concrete with alcohol. Resinoids are solvent extracts of resins and gums. CO2 extracts use carbon dioxide under pressure. Isolates are single components separated from a natural material. Each process captures a different part of the plant's scent, so the same plant can yield materials that smell quite different.
The main types
| Type | How it is made | Typical character | Examples |
|---|---|---|---|
| Essential oil (distilled) | Steam or water distillation | The volatile part of the plant; heat can alter some components | Lavender, vetiver, patchouli, rose oil |
| Essential oil (expressed) | Cold pressing of citrus peel | Fresh, bright; contains non-volatile components | Bergamot, lemon, orange |
| Concrete | Solvent extraction (e.g. hexane), solvent removed | Waxy solid or semi-solid | Jasmine concrete, orris concrete |
| Absolute | Concrete washed with ethanol; waxes removed; ethanol evaporated | Concentrated, often closer to the living flower | Jasmine, tuberose, rose absolute |
| Resinoid | Solvent extraction of resins, balsams, gums | Viscous, warm, long-lasting | Benzoin, labdanum, olibanum resinoid |
| CO2 extract | Supercritical or subcritical carbon dioxide | Often close to the raw material's smell; no heat damage | Pink pepper, ginger, vanilla CO2 |
| Tincture / infusion | Material steeped in alcohol or oil | Dilute; traditional | Vanilla tincture, ambergris tincture |
| Isolate | Fractionation or other separation of one component | A single note from a complex material | Natural linalool, natural citral |
Why the same plant gives different materials
Each method captures molecules according to their volatility and solubility, and each affects some of them. Distillation captures volatile components and can change heat-sensitive ones; solvent extraction captures heavier, less volatile ones that distillation leaves behind. That is why rose oil (distilled) and rose absolute (extracted) smell distinctly different, and why perfumers keep both. It is also why a material should be recorded by type, not just by plant: "rose" is not a material, "rose absolute, Turkey" is.
Practical differences in formulation
- Solubility. Absolutes and resinoids may contain components that are not fully soluble in alcohol and can cloud a perfume. Chill and filter, or pre-dilute.
- Color. Many absolutes and resinoids are strongly colored and will tint a finished perfume.
- Viscosity. Resinoids and some absolutes are thick and hard to weigh accurately; keeping them as dilutions helps (how to dilute aroma chemicals and raw materials covers the method).
- Strength. Absolutes are often much more powerful than oils from the same plant.
- Residual solvent. Solvent-extracted materials may contain trace residual solvent; the specification should state limits.
- Variation. All naturals vary with crop, origin and year — test each new lot.
Safety and restrictions
Natural materials carry their constituents into a formula, including restricted ones: furocoumarins in expressed citrus oils, allergens such as linalool, limonene, geraniol and citral in many oils. The IFRA Standards and labelling rules count these constituents wherever they come from. Ask suppliers for an allergen statement and data on restricted constituents for each natural, and use them when checking formulas — the comparison with synthetics is in natural vs synthetic fragrance materials.
Storage
Naturals are among the materials most affected by age, light, heat and air. Expressed citrus oils oxidize relatively quickly; many resinoids and some woody oils are much more stable. Keep them cold, dark and in well-filled containers, and date them on arrival and on opening. Fragrance raw material shelf life and storage covers this in detail.
Recording naturals
- Type (oil, absolute, resinoid, CO2 extract, isolate), plant, botanical name and part used.
- Origin and, where known, extraction method and year.
- Supplier, product code and lot.
- Allergen and restricted-constituent data, dated.
- Evaluation notes per lot.
The full set of fields is in the raw material documentation guide, and definitions of each material type are in the perfumery glossary.
Frequently asked questions
Is an absolute better than an essential oil?
Neither is better; they are different materials. Absolutes often smell closer to the fresh flower and are stronger; oils can be brighter and more volatile. Many formulas use both.
Are absolutes safe to use in perfume?
Many are used widely, within the limits that apply to their constituents. Check each one's restricted constituents and allergens, as with any material.
Written and reviewed by the RUŌOD Lab team. This article is general education about perfume formulation and record-keeping; it is not legal, regulatory or safety advice, and the examples are illustrations, not validated commercial formulas. How we write and check these guides.