This modern method implements solvents such as ethanol or hexane to isolate the oils. It’s often used for extracting essential oils from delicate aromatics, which are generally unable to withstand the pressure of steam distillation. Plus, solvent extraction typically produces a finer fragrance than most other extraction methods which further adds to its appeal for certain applications , Solvent Extraction happens in muti-phase process.
Concretes
Concretes are produced mainly from flowers (rose, jasmine, chamomile, etc.), but also from other plant materials (basil, geranium, clary sage, violet leaves, etc.). A yield between 0.2 to 0.35 % based on the starting flower material.
Fresh plant material is extracted with non-polar solvents ( Hexane ). the first phase is extraction of the concretes using the hexane solvent ,On evaporation of the solvent, a semi-solid residue of essential oils, waxes, resins and left behind is a waxy substance called a concrete ( aromatic concretes ).
The second phase is the extract of the absolute from the concrete ,
The aromatic oils are extracted from the concrete with ethyl alcohol, and after the ethyl alcohol is removed, the remaining substance is an absolute – an oil with an aroma close to the plant from which it came. An absolute is the most concentrated form of fragrance and highly regarded in natural perfumery.
Waxes considered as a by product substance after the end of the solvents extraction process.
Absolutes still contain some waxes and pigments along with other constituents from the plant, but are mostly comprised of the concentrated aromatic material that can range in consistency from mobile to quite viscous and even solid.
