Solvent extraction is often used for gums and resins, but also for other plant materials. It involves covering the plant material in a solvent, which may be a petrochemical, and then extracting the essential oil by filtering the plant material and evaporating the solvent. While this method may be perfectly acceptable to the perfume trade, good aromatherapy companies try to avoid buying essential oils and absolutes produced using petrochemical solvents.


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