The process: how does an essential oil get made?
Part art, part science, different distillation methods are used for different plants to most optimally extract their ‘essence,’ i.e. transform them from plant, bark, petal, or leaf into essential oil. A specific method might be chosen based on how delicate a flower is, what consistency it starts off as, and the desired output. Even within each method there can be great variances – for e.g. how long it takes, what type of pressure is applied, the temperature used, etc.We primarily use 4 different extraction methods for our oils: hydro distillation, solvent extraction, alcohol extraction, and CO2 extraction.
Hydro distillation uses water to gently extract fragrance from flowers and transform them into oils. We use this distillation method to extract our chamomile oil, lavender oil, neroli oil, rose oil, clary sage oil and sandalwood oil.
In the hydro distillation method:
- Flowers (or stems, leaves, petals) are added to a big tinned copper or stainless steel container
- Water is then added to the container until filled up
- The water is heated and when it reaches 100°C, the temperature is maintained
- At this stage, water (which is now mixed with the fragrant flowers) evaporates through a small pipe and travels to a condenser
- In the condenser, the evaporated water cools and returns to liquid form – called distillate. The condenser temperature is maintained at 35°C to avoid premature solidification
- The distillate is collected in Florentine flasks, where we see a separation of liquid and oil because of the different densities of each substance
- What floats on the water’s surface is a layer of oil, and in our case, chamomile oil, lavender oil, neroli oil, rose oil, clary sage oil and sandalwood oil.
Solvent extraction is commonly used for flowers that are quite delicate. We use this process combined with alcohol extraction (below) to extract our jasmine absolute sambac, and rose absolute.
In the solvent extraction method:
- Flowers are loaded into an extractor, which looks like an empty bird cage with shelves, and a rotating drum.
- A solvent is added to the extractor, which ‘washes’ through the flowers by the rotating drum (think a washing machine without the water), and draws out the flowers’ fragrant components.
- The flowers go through 3 ‘wash’ cycles with additional solvent pumped into the extractor after each wash.
- After the 3 ‘washes,’ the now fragrant solvent is filtered and pumped into a concentrator. It’s then heated to 60°C, which allows the solvent to slowly start evaporating.
- The resulting substance is transferred to an evaporator, where it is again heated at a low temperature to get rid any remaining traces of solvent.
- This results in what’s called a concrete, a wax-like substance that solidifies at room temperature.
Some perfumers might use a concrete at this waxy consistency, but we transform it into an absolute using a process called alcohol extraction.
To transform a concrete [the wax-like substance from the solvent extraction phase] into a fully soluble absolute, a process called alcohol extraction is used. This is the final step of extraction for jasmine sambac absolute and rose absolute. Benzoin goes through this step as well.
In the alcohol extraction method:
- The ‘concrete’ is melted by a water bath and dissolved in ethyl alcohol.
- It is then stirred for an hour in an apparatus called a batteuse, which results in liquid being separated from insoluble wax.
- The insoluble wax is removed, and the liquid is cooled.
- The process is repeated once again to remove any remaining insoluble wax.
- Finally, the liquid is heated at a low temperature to remove alcohol, leaving us with our absolutes of rose, jasmine sambac, and benzoin.
Carbon dioxide extraction
Carbon dioxide (CO₂) extraction is a method used to extract a plant essence by using carbon dioxide as a solvent. It is used to extract our cardamom CO₂ extract, and preserves components within cardamom better than other extraction methods.
In the CO₂ extraction method:
- Pressurised carbon dioxide is pumped into a chamber filled with the plant or flower. The pressure makes carbon dioxide have liquid like properties, while technically still being a gas.
- Since the carbon dioxide now acts like a fluid, it functions as a solvent and pulls the ‘essence’ components out of the flower.
- Once the aromatic oil is extracted from the plant, the pressure in the chamber is lowered. This returns the carbon dioxide back to its gas state and allows it to completely dissipate, leaving us with our pure cardamom extract.
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