Expression

The technique of expression

Cold expression, or cold pressing, is a process reserved for fruits, and more specifically for citrus fruits. The essential oils of these plants are contained in small glands located in their peel. The idea is to subject the peel to strong pressure using a press in order to obtain a juice known as the absolute. This process is without doubt the simplest of all the know-how involved in perfumery. It does not alter the base product in any way, so the scent of the raw material is all the more faithfully preserved. It is also a technique widely used in aromatherapy. Thanks to this method, the therapeutic qualities of each ingredient are preserved. Nevertheless, the main drawback of expression remains the limited shelf life of the products obtained. Since they are cold-pressed, their raw shelf life (before their essence is incorporated into a finished fragrance) does not exceed six months. Finally, as an example, it takes about 1500 lemons, 1500 bergamots and 1000 citrons to obtain about 1 kg of their respective essence. Likewise, it takes about 1000 oranges to extract about 500 grams.

The two methods of expression

Cold expression is a technique that originated in Sicily. After all, what could be more logical, considering that it is one of the main producers of citrus fruits? In the past, expression was done by hand, through a process known as the sponge method. The citrus fruit was cut in half, emptied of its pulp, and its peel was thoroughly soaked. After being left to rest for about ten hours, it was then pressed to release its essence onto an assembly of sponges fixed to a basin. After settling, the fruit's essence was then collected in a vessel by wringing out the sponges. However, this method has now given way to industrialization. Expression is now carried out in two ways. It is possible to use a whole fruit and press it: the juice is then separated from the fruit's essential oil using a centrifuge. The other method consists of removing the peel of the fruit and grinding it, since it is the peel that contains the essential oils needed to create a fragrance.

As can be seen, expression is a relatively simple technique that does not involve exorbitant costs and that has been known for centuries. However, since it applies only to citrus fruits, perfumers have had to show great ingenuity in order to use the scent emanating from other plants…