Very delicate plants and flowers such as Jasmine blossoms cannot survive the process of distillation and to extract the essences a process of solvent extraction is frequently used. In this process trays of blossoms are washed with a solvent (hexane) which dissolves all the extractable parts, aromatic molecules, waxes and pigments.
The resulting solution is then filtered to recover the solvent for reuse. The remaining waxy material is called a concrete.
The concentrated concretes can be processed further to remove the waxy materials by warming it and stirring it with ethanol which breaks the wax into tiny globules allowing the smaller molecules of the essence to separate.