January 19 2017
There are many different ways to extract essential oils from different plants and each method results in something a little bit different. Some methods are more suitable for some plants than with others, but each method, when done properly, will result in essential oils being made. Here are the different methods.
Steam distillation is one of the better known methods for extracting essential oils from plants and has been done since before the middle ages. Freshly picked plants are placed over boiling water and the steam progressively pulls the oils out of the plant which is kept in a small chamber suspended over the boiling water. The hot steam releases the aromatic molecules of the plant(s) by opening up whatever pores in the plants contain these molecules. This steam, now containing the essential oil from the plant is rapidly cooled down and the oil separates from the water.
A very direct method of extracting essential oils is expression, which is when you press down on whatever part of the plant you choose to extract oil from. This is commonly used for many citrus type essential oils because the oils in the skins of these fruits are most easily pressed out.
This method is rather old and hardly used but still noteworthy. This is typically used with flower based essential oils where the blossoms would be set on a layer of glass covered by a layer of warm fat (originally animal fats were used, now it’s more vegetable based fats). Eventually the essential oil would be blended in with the fat and the used flowers would be replaced with new flowers and this is repeated until the fat is completely infused with the fragrance and then the fat and the oil are separated.
While many aromatherapists tend to not use this method for fear that some of the chemicals from the solvents will remain in the finalized oil, they are typically completely removed and are another useful way to extract essential oils and is a method that is used a lot in the perfume industry. First, the plant selected is dissolved in a solvent like benzene, hexane. Next, the solvent, which is at a low boiling point, is evaporated off and the resulting oil is called an “absolute”.