The absolute of some delicate flowers is extracted using solvent extraction, a method that was first tried in the 1830s and became commercially available by the 1890s.
The process of collecting essential oils using the extraction method is as follows.
- The petals are first placed on a perforated shelf, i.e., a shelf with holes in a completely sealed container, while several containers are connected by a channel, but are completely sealed to the outside.
- At one end of the channel is a vat of liquid solvent, while at the other end of the channel is a vacuum container.
- The liquid solvent is activated so that it flows slowly through each petal, allowing the essential oils contained in the petals to dissolve in it.
- Distillation of this solvent results in a semi-solid fragrance substance, the “condensate”, and the distilled solvent can be returned to the channel for reuse.
The condensed body contains a lot of fragrance substances from plant bodies and natural plant waxes. 25 grams of the condensed body is equivalent to 1 kg of high-quality balsam (obtained by liposuction).
The treatment of the body is very similar to that of the balsam. After shaking the condensate in alcohol and removing the vegetable waxes that cannot be dissolved in the alcohol, a high-quality absolute is obtained.
In the 19th century, the solvent used at the beginning was petroleum ether, which was later changed to benzene.
Modern extraction methods tend to use liquid butane or liquid carbon dioxide, which do not destroy the aroma molecules and therefore give very good quality extracts.