The Different Methods of Essential Oil Extraction Explained

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Reviewed by:  Kacie La

Have you been wondering how oil extraction processes produce the essential oils you use and love? Well, you’re in luck because this article explains all essential oil extraction methods!

Are these modern methods?

Some of them are, but people have reportedly been engaged in essential oil production since 4500 BC , pioneered by the Egyptians, who used them for cosmetic purposes and mummification.

Even some of your beloved essential oils todaywere first discovered and formulated by Egyptians, Romans, and Greeks. This means some oil extraction processes were discovered ages ago!

It’s just fascinating how humans thought of extracting essential oils of different varietiesfrom natural plant materials. And now, we have essentials for skin and beauty , hair care, and a wide range of other uses!

The question now is, how do you extract essential oils?

Well, if you’ve been wondering the same thing, then keep reading to learn how essential oils are extracted and what’s the best way to extract essential oils?

HOW ESSENTIAL OILS ARE EXTRACTED

1. Steam Distillation

This is one of the oldest methods of essential oil extraction and remains one of the most popular and commonly used methods to this day.

The steam allows the plant’s pores to open and vapourises the volatile compounds within the plant material. This eventually goes through a condensation tube and is collected in a separate container.

Process

Pressurised steam is injected into the Still, a large container with the plant material. This vapourises and releases the plant’s aromatic molecules which travel through two pipes: one pipe allows hot water to exit and one pipe for the cold water to enter the Condenser, turning the vapour to cool back into liquid form.

The molecules drop from the Condenser and into the Separator, containing water, where the oil floats and is collected.

Advantages

1. Highly applicable to most plant materials and for both small and large amounts of raw materials
2. Retains their original properties and aroma

Disadvantages

1. Might reduce the quality of some delicate raw materials due to the high temperatures
2. Process can be time-consuming, especially for hard or wood-based plants

2. Solvent Extraction

This essential oil production method uses food-grade solvents, such as hexane and ethanol, to separate essential oils from plant material.

Solvent extraction is the best way to extract essential oils from plant materials that produce relatively small amounts of essential oils, largely resinous, or materials vulnerable to pressure and distress of steam distillation, such as benzoin.

Solvent extraction is also used for delicate flowers such as rose, jasmine and frangipani which easily lose their fragrance at high temperatures set during steam distillation. The resulting concentrated oil is called an Absolute oil

Compared to other essential oil extraction methods, solvent extraction produces a finer fragrance and other by-products, like waxes and pigments.

Process

The plant material is prepared and placed in a container, then the solvent is added in order to separate the oil. The solvent then evaporates via vacuum distillation, leaving the oil, which is further purified through additional distillation from the remaining solvent.

Advantages

1. Requires little energy to conduct
2. Maintains the original scent of the origin plant

Disadvantages

1. Limited applicability, mainly blossoms that can’t withstand high temperatures and resinous materials.
2. Solvent-extracted oils quickly oxidise

3. CO2 Extraction

CO2 extraction is a relatively new and yet highly efficient way of extracting a variety of oils. Extracting essential oils using this method involves the use of pressurised carbon dioxide (CO2) as a solvent, producing oils without heat.

Thus, compared to heat-based oil extraction processes, CO2 extraction yields higher-quality oils and retains most of the nutrients and qualities of its raw plant material, including its aroma.

Also, CO2 is colourless, odourless, and easily released, making it harmless to human contact and the environment. Because of this, some of your skin-loving essential oils may have been produced using CO2 extraction!

Process

CO2 becomes liquid once pressurised whilst remaining in a gaseous state, meaning that the CO2 is “supercritical” which is then added to the plant material as a solvent. The pressure in the e xtractor container is drecreased and this lets the CO2 evaporate; what’s left is the extracted essential oil. And that is how essential oils are extracted using CO2 extraction!

Advantages

1. Extracted oil is highly pure, solvent-free, and retains most of the plant material’s nutrients and properties, resulting in a high-quality oil
2. Harmless and environmentally friendly as CO2 is a reusable solvent

Disadvantages

1. More costly than traditional methods
2. Needs advanced equipment and technical knowledge

4. Maceration

Maceration is among the oil extraction processes people use today. Extraction of essential oils with this method uses carrier oils, such as olive or sunflower oil, as solvents, and the end product is referred to as ‘infused oils.’



Extracting essential oils via maceration requires the plant material to be as dry as possible as any hint of moisture may lead to microbial growth and the oil becoming rancid, although mixing 5% of Vitamin E oil or Wheatgerm oil may help avoid rancidity.

Process

With the maceration extraction of essential oils, the plant material is crushed or ground into powder form, placed in a closed container, and mixed with solvent ie carrier oils in this case. This mixture is kept for 1 week and shaken at different intervals.

Then, the liquid is strained and clarified through filtration and poured into an airtight container, and can now be used for up to 12 months.

Advantages

1. Easy to conduct and requires minimal equipment
2. Preserves properties of plant materials, even delicate ones

Disadvantages

1. Produces oils with lower concentration
2. Oil quality depends on the base carrier oil used

5. Enfleurage

This is among the oldest essential oil production methods that use odourless and solid fat. Extracting essential oils using this method can be implemented in either “hot” or “cold” procedures, with the cold process taking much longer time while the hot procedure compromises the end product’s quality.

Process

Purified and odourless vegetable or animal fat is spread out and set in the chassis, or glass plates in a frame. Plant materials are placed on top of the fat layer and pressed in for 1 day up to several weeks, based on the plant material.

This allows the scent of the plant materials to seep into the fat (cold enfleurage), or you may heat the fat layer to speed up the absorption process (hot enfleurage).

Plant materials are replaced with fresh batches until the fat achieves its desired state: the enfleurage pomade, a combination of fat and fragrant oil. The oil is separated from the fat using alcohol until the alcohol is left to evaporate, leaving behind the oil, which is usually called an Absolute oil.



Advantages

1. Preserves delicate floral fragrances often lost when using distillation or solvent extraction methods
2. Requires simple tools

Disadvantages

1. Time-consuming and needs large amounts of plant material to produce a small amount of fragrance; thus, the end product is sold more expensive

6. Cold-Press Extraction

Most of the essential oil production methods discussed above involve heat but, as you know, this can compromise the quality of the essential oil. So, how do you extract essential oils without using heat?

Use cold-press extraction, an essential oil extraction method, also called ‘expression’ or ‘scarification,’ that extracts oil from plant materials without heat.

This is known as the best way to extract essential oils from citrus oils, such as oranges, lemons, and bergamots, and involves pressing the plant materials to produce the eventual oils.

Process

Cold-press extraction of essential oils begins with piercing the entire fruit or plant material, allowing the essential oil and pigments to flow into the collection container.

The entire fruit is again squeezed out, and the collected extracts are filtered to remove residues. The oil is separated from the juice layer and is transferred to another container for use and storage.

Then, the liquid is strained and clarified through filtration and poured into an airtight container, and can now be used for up to 12 months.

Advantages

1. Requires minimal energy vs. other essential oil extraction methods
2. Generates high-quality oils without the use of solvents

Disadvantages

1. Produces lower quality oil as it is prone to oxidisation vs. other essential oil extraction methods

7. Water Distillation

Delicate flowers, like roses and orange blossoms, tend to clump together when steamed. So, how do you extract essential oils from these plant materials?

The best way to extract essential oils from these plant materials is by soaking them in pure boiling water in a method called ‘water distillation.’

Process

Plant materials are submerged in heated water. The presence of water creates a protective barrier on the extracted oil, preventing it from overheating.

Extracts are cooled, and the oil is separated from the leftover water, which often contains fragrance and is turned into an hydrosol, or floral water.

Advantages

1. Hygienic method that offers effective extraction

Disadvantages

1. Reduced properties from plant material due to heat
2. Time-consuming as the process can take several hours
3. Limited applicability to some plant materials due to their specific properties, such as citrus oils
4. Yields less oils

SUMMARY OF EXTRACTION METHODS

Commercial-grade essential oils & their extraction process

Commercial-grade essential oils are made of 100% pure essential oils mixed with natural ingredients and/or nature-identical materials. These are typically produced via cold-press and water distillation methods.

Commercial-grade essentials oils offer excellent fragrant profiles for more cost-friendly rates, compared to purer yet higher-priced Conventional 100% Pure Essential Oils (not blended nor formulated) or Blended 100% Pure Essential Oils (mix of 100% Pure Essential Oils of same botanical name but from different places of origin).