You may already know why essential oils are great for improving your wellbeing in all sorts of ways and that the best products are completely natural. But how do the healing properties of plants, flowers, and herbs make it into oil form? To fully appreciate essential oils, it’s useful to understand how they come to be.
Extraction from Plants
Referring to the process of creating essential oils as “making” them is not entirely accurate, since the oils are extracted from plants rather than synthesized. The extraction process removes beneficial components and stores them in liquid form. It involves condensing botanical compounds and removing other material, which results in a product that is more potent than the whole plant.
To create this extract, the plant is added to a solvent, which aids in the breakdown of the plant material. Some compounds in the plant diffuse out of the organic material and into the solvent. The liquid that results from this process is the essential oil. The solvent often continues to play an important role by preserving the beneficial compounds of the plant.
Methods to Extract Essential Oils
There are a few different methods that can extract essential oils from plants. Steam distillation is the most common, but it’s only one of the several ways used to create the wide range of essential oils available for purchase.
As the name suggests, steam distillation involves using heat to separate essential oils from their plant material.
The plant is placed in a distilling apparatus called a still, usually made of stainless steel. Steam from boiling water enters the apparatus through an inlet, causing temperatures to reach between 140 and 212 degrees Fahrenheit. This makes the plant release the aromatic compounds that will become the essential oil.
These compounds rise to the top of the still, along with water, in the form of vapor, and they exit into a condenser. Cold water flows through the condenser to turn the vapor into liquid. Since the oil naturally remains separate from water (usually floating on the top, but sometimes sinking to the bottom, depending on the type of oil), it becomes possible to separate the essential oil from the water.
To gain essential oils from herbs, carbon dioxide extraction is often the ideal method. This can lead to higher-quality essential oils than with steam distillation because the method prevents altering the characteristics of the plant, which can happen to certain herbs when they’re exposed to high temperatures.
The CO2 extraction process is much like steam distillation, with the difference that carbon dioxide acts as the solvent. As a result, temperatures only need to reach about 100 degrees Fahrenheit.
This keeps the molecular composition of the essential oils much more similar to that of the plant matter and the oils contain more of the plant, resulting in a thicker product.
Carbon dioxide extraction is completely safe — just as safe as using heat. After all, growing plants need carbon dioxide as a fuel source and we breathe out CO2 in every exhalation. Plus, the method uses no chemical solvents that could be harmful to your health.
CO2 extraction simply involves pressurizing carbon dioxide to the extent that it becomes supercritical — meaning it is in both a gaseous and liquid state. Carbon dioxide is then pumped into the chamber containing the herbs, where it works as a solvent to separate essential oils from plant matter. These oils dissolve into the liquid CO2. When carbon dioxide is brought back to normal atmospheric pressure, it returns to a gaseous state and only the essential oil remains as a liquid.
Solvent extraction is typically used when plants only contain small quantities of essential oil, materials are mostly resin, or delicate oils would be damaged by steam distillation. This involves treating the plant material with hexane, ethanol, or another food-grade solvent, which results in a combination of wax and oil called concrete. To separate the oil from the wax, it is necessary to mix the concrete with alcohol and then heat the solution in a vacuum distillation chamber to remove the alcohol. Finally, the vapor passes through a condenser, leaving the essential oil in liquid form.
Cold Pressing Extraction
Also called expression and scarification, cold pressing is the most common method used to obtain essential oils from citrus fruits. After being washed, the fruit is placed, in its entirety, on a tray in a mechanical device that spikes or grates it. This breaks open the sacs on the internal side of the rind and releases the essential oils.
Next, the device sprays the fruit with water and squeezes it to release the rest of the essential oils and juice, which collect underneath the tray. Centrifugation separates the essential oils and juice from the solid matter, and these oils are then siphoned off.
Finally, there’s maceration. This involves chopping up plant material until it forms a powder and putting it in a container with carrier oil, which will act as a solvent. The mixture stays sealed in the container for a week and is undisturbed except for the occasional shaking. Once the week is up, the mixture is strained through a funnel. The solid residue is pressed to remove any remaining essential oil and this is also strained. The oils produced from both are mixed together and the resulting product clarified using either filtration or subsidence.
This option is ideal for preserving more qualities of the plant, since large molecules that may have been lost by other methods remain in the oil. Maceration works best for plant material that can be fully dried before the process to prevent microbes growing within the sealed container. It is common practice to add vitamin E oil or another product that is high in vitamin E to prevent the essential oil from turning rancid.
It’s important to always choose high-quality essential oils that are completely free from synthetic ingredients. LaCura has a range of essential oils to boost immune system functionality all year round. Check out our store to find the perfect blend or single for your needs.