While we can say without a doubt that essential oils are an essential part of aromatherapy, the term "essential", in this case, does not mean "being a necessary part of".
In the practice of aromatherapy, essential oils are the fragrant oils extracted from the "essence" of a plant, or, those parts that contain the plant's aroma molecules.
The many different methods of extracting essential oils can be confusing to the novice, However, the option of using different methods of extraction guarantees that the highest concentrations of oils can be extracted under various situations.
Essential oils can be extracted from many different types of plants, and many different parts of those plants as well. The plants' flowers, fruits, herbs, stems, roots, leaves, buds, blossoms, seeds, nuts and even tree bark can produce some of the most aromatic and therapeutic essential oils.
The methods of essential oil extraction fall into three main categories: expression, solvent extraction and distillation.
Following is an overview of the common extraction processes and methods.
The expression method of essential oil extraction is popular in many instances because it does not involve the use of a heat source, as does distillation.
Expression is a common method for extracting oils from the rinds of citrus. In earlier eras, rinds of these fruits were squeezed by hand and a sponge was used to collect the essential oils. The fruit itself would be removed and the rinds, along with the pith, would be soaked in water to make them easier to work with.
Then, they would be turned upside-down!
The purpose in turning them upside-down is to cause the cells containing the oils to break apart. Once broken, the oils would drip out and soak into a sponge. Once the sponge became saturated, the oils would be squeezed into a container to be decanted.
Ecuelle a Picuer
Another expression method of extracting essential oils involves sticking pins into the skins of fruit for the purpose of damaging the cells that contain the sought-after essential oils. The apparatus commonly used had a built-in container for collecting the oils and the other parts of the fruit that also ended up in the collection area. The final steps involved separating the essential oils and, again, decanting them. This is called the ecuelle a picuer method.
Those previous processes are quite labor-intensive, but, technological advances have led to the invention of machines to do this sort of tedious work. In our modern mechanical era, oils from rinds are extracted using centrifugal force. This high-speed process is called Machine Abrasion.
This popular, and often preferred, method of extraction of essential oils is commonly used to extract essential oils from nuts and seeds and from the rinds of citrus. Cooks are familiar with "cold pressed" olive oil, which is usually considered to be of better quality than others.
Essentially, no pun intended, in this method mechanical pressure is used to force the oils out of the plant material. The oils extracted in this way contain water, but this water will, in time, evaporate, leaving just the desired essential oils. Although popular with purists, one disadvantage of using this extraction method is that cold pressed oils generally spoil more quickly than those extracted using other methods. That's why, in order to eliminate waste, it's important to purchase these types of essential oils in smaller quantities.
Benefits and Basics of Aromatherapy