Essential oils are natural, volatile constituents which are found in various plant parts, including the leaves, bark, fruit, flowers, berries, seeds and more. Only a relatively small proportion of the plant population contains these oils which are mainly produced for the plant's defence or survival purposes.
Essential oils are the liquids that are isolated from the plant when it is extracted. Extraction is the process of taking this botanical constituent from the plant, essentially now a ‘liquefied version of itself’, ready to use for aromatherapy and fragrance purposes,
The methods of extraction vary from plant to plant and depend on the type of plant material being used and where the oil is located in the plant. The method used dictates the product produced - a rule of thumb is that enfleurage and solvent extraction produce concretes and absolutes, such as rose and jasmine, and steam distillation and Co2 extraction produce essential oils.
Here we look at the different methods of extraction used to create essential oils…
Steam distillation
Perhaps the most historical and widely used method, steam distillation involves heating the plant material in a still where the steam permeates the plant material, releasing the plant’s aromatic molecules and turning them into vapour. The vapour and steam produced are then cooled, turning back into liquid form as the steam becomes a watery distillate and the volatile essence turns into the essential oil, collecting at the top as it is lighter, where it is then separated off. The water remaining is known as hydrolat, or flower water, quite often used in toners and as an aromatic by-product for use in other cosmetic preparations in place of, or in addition to water.
Essential oils which are made in this way include Basil, Eucalyptus, Lavender and Petigrain, as well as many more.
Expression
Otherwise known as cold-pressing, expression is used predominantly for oils derived from fruit peel, citrus fruits in particular. The essence is contained within the fruit peel and is extracted through pressure to essentially squeeze the oils out, helping to retain all the aromatic goodness - when someone peels an orange nearby, and you smell the fruit across the room, that is the release of the essential oils from the peel.
A small amount of juice is often expressed too which is then separated from the oil. Essential oils which are extracted in this way include Bergamot, Mandarin and Grapefruit.
Solvent extraction
This method of extraction is used for plant material that is too delicate for steam distillation or which has little essential oil. Essential Oil Absolutes are created from the most fragrant and delicate flowers such as Neroli, Jasmine and Rose. The solvents used dissolves the non-volatile compounds in the plant and is then evaporated to leave a waxy compound, known as ‘concrete’ which typically contains half essential oil and half wax.
A second phase of solvent extraction is then undertaken using ethanol to remove the wax. Although small traces may still be found. Certain oils are then further processed by ‘molecular distillation’ which can remove all traces.
This process results in an extremely concentrated form of oil, Absolute, which due to the fact that they contain more material than essential oils, are considered to be ‘absolutely complete’ in their aromatic quality, often smelling almost exactly like the original flower and therefore attracting a higher price.
Essential oils extracted in this way include Rose damascena, Jasmine and Violet.
Enfleurage
One of the oldest methods of extracting and not commonly used today, enfleurage uses animal and vegetable fats to extract the fragrant compounds of a plant/flower. The essential oil diffuses into the layers of fat as it’s left for a number of days or weeks. The fat that is saturated with fragrance is called ‘enfleurage pomade’ before being washed by an alcohol solvent to separate the botanical extract from the fat. The remaining fat is often used for soap-making. Once the alcohol evaporates from this mixture, the ‘Absolute’ is what remains.
Essential oils created in this way include Frangipani, Honeysuckle and Tuberose.
CO2 extraction
A relatively new form of extraction, this technique freezes and compresses carbon dioxide, then passes the cold CO2 liquefied gas through the plant, pulling all of the essential oil-soluble and water-soluble elements out of the plant material, producing a highly concentrated oil. C02 is colorless, odorless, and can be easily and completely removed. One of the main benefits of using CO2 is that it can extract a wide range of essential oils, including those sensitive to heat and damaged by traditional steam distillation methods.
It is also considered a sustainable method of extraction due to the absence of solvents.
Oils extracted in this way include Ginger, Turmeric and Vanilla.
Maceration
Although not strictly classed as essential oils, when extracted in this way - maceration is a way to produce carrier oils, with added plant properties. Macerated oils are also referred to as ‘infused oils’. They are created when carrier oils, such as olive or sunflower, are used as solvents to extract therapeutic properties from plant material. The flowers are soaked in the hot carrier oil which breaks down the plant membrane and allows the oil to absorb its ‘essence’. This is then strained with the flowers being removed and often, other liquids can be mixed in at this stage depending on the desired final use. Essential oils are fragrant, but carrier oils are not.
Oils such as Calendula, which we use in our Beauty Balm, Face & Body Oil and Massage Balm. are created in this process.
Discover our range of essential oil blends, created in-house using high-quality ingredients, both ethically and responsibly-sourced.