Concrete
In perfumery a concrete is the waxy, semi-solid mass left after solvent-extracting flowers like jasmine and rose — washed with alcohol, it yields an absolute.
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In perfumery, a concrete is the waxy, semi-solid mass you get when you extract fresh plant material — usually flowers — with a nonpolar solvent and then drive the solvent off. What stays behind is everything oil-soluble the plant had to offer: the volatile aroma compounds, but also waxes, pigments, and resins. That wax load is why a concrete is thick and often solid at room temperature rather than a free-pouring oil, and it's the whole reason the material rarely goes into a fragrance as-is.
The concrete is an intermediate, not a finished material. To make it usable in alcoholic perfumery, a perfumer washes it with ethanol: the fragrant molecules dissolve into the alcohol while most of the wax does not. Chill the solution, filter out the precipitated wax, then distill off the ethanol, and what remains is the absolute — alcohol-soluble and far more concentrated. The numbers vary by flower, but a rose concrete runs roughly half wax, and yields on the order of 60 percent absolute. Concrete and absolute are two stages of one process, which is why the pair is almost always discussed together.
Solvent extraction exists because steam distillation doesn't work for every flower. Jasmine, tuberose, narcissus, and mimosa are too delicate or yield too little oil to survive distillation's heat, so they're captured as concretes instead — which is why most jasmine and tuberose in modern perfumery is an absolute, not an essential oil. Rose is done both ways: distilled into rose otto, and solvent-extracted into rose concrete and absolute. Concretes themselves still appear directly in soap and solid wax-based bases, where the wax is an asset rather than a flaw.
- Concrete
- The waxy, semi-solid mass obtained by extracting fresh plant material — most often flowers — with a nonpolar solvent such as hexane, then evaporating the solvent. It holds the plant's volatile aroma compounds alongside roughly 50 percent waxes, pigments, and resins, which makes it too thick and too cloudy to use directly in an alcoholic fragrance.
- Absolute
- The alcohol-soluble extract made from a concrete. Washing the concrete with ethanol dissolves the fragrant compounds but leaves most of the wax behind; cold-filtering and distilling off the alcohol gives the absolute. Closer to the living flower's smell than a distilled oil, and the form most florals reach perfumers in.
- Essential oil
- The aromatic oil obtained by steam distillation or cold expression rather than solvent extraction. It carries only the volatile, distillable fraction of the plant — no waxes — which is why it differs in character from an absolute of the same flower and why heat-sensitive blooms can't be captured this way.
- Solvent extraction
- The method behind concretes and absolutes: dissolving a plant's aromatic and waxy material in a volatile hydrocarbon, then removing the solvent. The standard modern choice is hexane, having replaced earlier petroleum ether and the long-abandoned benzene.
- Pomade
- The fat charged with floral scent in enfleurage, the cold-fat capture method that predates solvent extraction. Washing a pomade with alcohol yields an enfleurage absolute — the same alcohol-wash logic that turns a concrete into an absolute, applied to fat instead of a solvent residue.