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Concrete, in perfumery, is a waxy mass obtained by solvent extraction of fresh plant material. It is usually used for the production of absolutes, which are highly concentrated and aromatic oily mixtures.

Production
Fresh plant material is extracted with nonpolar solvents (e. g. benzene, toluene, hexane, petroleum ether). On evaporation of the solvent, a semi-solid residue of essential oils, waxes, resins and other lipophilic (oil-soluble) plant chemicals remain.

The resulting residue after evaporation consists mostly of heavier nonvolatile substances like waxes and resins, which gives concrete its "waxy" properties.

Putting the plant materials under high pressure before treating it with solvents has been found to greatly increase the yield of the concrete.

Uses
The main use of concrete is for producing absolutes. Concrete may be extracted with ethanol to produce an absolute. Absolutes are highly concentrated and aromatic oily mixtures that are similar to essential oils. They are completely soluble in ethanol and can be used as perfume ingredients.

Concretes are only partially soluble in ethanol due its composition of heavier substances. Therefore, they are of limited use in perfumery, but they can be employed for scenting soaps.

Issues
The first issue with using concretes in perfumery is that their extracts can become rancid after several months, especially if the containers are exposed to strong light.

The second issue is regarding residual pesticides in concretes. Cultivation of natural raw materials for producing concretes is often done by using monoculture techniques that use pesticides. There are laws regarding permitted residual levels of pesticides used in cultivations of raw materials. However, currently, there is no universal method for analyzing the amount of residual pesticides in concretes that could show if the amount of residual pesticide in a concrete sample is safe. Previous analyses used methods like gas chromatography, but they were heavily affected by the different components of the complex mixture of concrete samples. Therefore, it is likely that their analyses of the amount of pesticide in concrete was inaccurate. This is a concern, as a level of pesticide in concrete that is above the safe limit could lead to health risks.