Odorants are a very important factor in the creation of perfumes. They are basically obtained by drawing out aromatic compounds from suitable raw materials which are obtained from parts of the plant or other natural sources. Although they can be created through synthetic methods too, the natural methods used in extraction of essential oils are far more superior and in demand. The whole procedure of extraction of odorants requires it to go through several processes.
There are different methods employed for the extraction of essential oils from natural sources, like distillation, solvent extraction, expression, enfleurage, etc. The method used depends upon the nature of the raw materials. These processes results in end products like essential oils, absolutes, concretes, or butters according to the wax concentrate on the extract.

Expression is one such process employed in the extraction of aromatic compounds. In this method, the raw materials used are squeezed, pressed, or compressed to extract the oil from it. This is a technique which is frequently employed in the extraction of oils from fruit peels, especially of those which fall into the category of the citrus family. The peels from such fruits contain a large amount of oil and hence expression is one method where all the oil can be taken out in the most economically viable manner. Normally, the peels are cold pressed or expressed mechanically for the maximum benefit.

Expression, as a method of extraction is a comparatively low cost method and when combined with the easy availability of raw materials, it is generally seen that citrus oils are cheaper in the market than other aromatic oils. Examples of such oils are lemon and sweet orange oils that are among the low cost oils in the aromatic industry.

The method of expression has been in use since very ancient times, as can be found in traditional Egyptian practices. It came into the picture long before distillation. Conventionally, the ancient Egyptians used to press the raw plant material and bury it in the dessert for a few months in unglazed ceramic utensils to dry out the water content which naturally used to get diffused through the pores of the ceramic vessel. What would remain inside the pot was the oil, which used to be taken out. It can be seen that scents obtained in such a manner still managed to retain its fragrance even after 3000 years, as can be proved from the lotus oil found in sealed alabaster vessels which were found in Tutankhamen’s tomb.

Tim Walt