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Making Essential Oils: Distillation, Cold-Press Extraction and Solvent Extraction


How are essential oils created?

Essential oils are natural oils typically obtained by the process of distillation. These oils tend to share characteristics of the plant or other sources from which it has been extracted. Think of these oils as the liquid form of the original source. Fruits, vegetables, spices, bark etc are all filled with vitamins and nutrients that make each plant special in their own unique way. By extracting the essence of a plant we are getting the most potent part of that plant for easy absorption and we introduce a new purpose for that plant, like topical skin-care. This allows us to take organic living to a whole new level, plant based skin care! We can target the exact nutrients our skin needs and apply them directly to our skin for fast absorption.

The essence of nature’s finest nutrients can be found in essential oils. If you’re like us, you're probably wondering, how do we get those yummy nutrients out of these plants! The answer is much simpler than you probably imagined. Not all plants can be extracted effectively through each method. Citrus fruits for example, use the Cold-Press Extraction (also known as Expression) method simply because the essence is found the peels. Throughout history these processes have been passed down as the most effective methods for producing these wonderful essential oils.

Essential Oils

  • Created by way of Distillation and Expression (Cold Pressing).

Absolutes

  • Created by way of Solvent extraction, or Enfleurage.

CO2 Selects/Extracts

  • A somewhat new method, but slowly making its way to being readily available. Essential oils or CO2 Selects are created with low CO2 pressure.
  • Totals are obtained with higher CO2 Pressures and contain all soluble components including the wax, resin and pigments. This resembles a hexane extract without leaving a solvent residue. These Totals are usually pasty and thick due to it collecting all the fats, resins and waxes from the desired plant.

3 Methods for Extracting Essential Oil

  1. Distillation
    1. Steam
    2. Water
    3. Water and Steam
  2. Cold-Press Extraction
  3. Solvent Extraction
    1. Hypercritical Co2 Extraction
    2. Maceration
    3. Enfleurage

DISTILLATION

This is the most popular method for extracting essential oils. Within the Distillation spectrum you have three different methods. Water Distillation, Water and Steam Distillation, and Steam Distillation. The temperature, plant type and time invested into this process are major factors in quality of these essential oils.

Steam Distillation

The Process:

  • The plant is placed into a large container known as a Still.
  • Steam is injected into the Still, causing the plants essence to vaporize.
  • The vapor is then funneled through a Condenser. The Condenser is encased in cold water, which forces the vapor to turn back into a liquid.
  • Once in liquid form it travels to a Separator. Since oil and water do not mix the Essential oil can be found floating on top of the hydrosol beneath and is eventually siphoned off. (In some cases the essential oil can be heavier than the water forcing it to the bottom of the separator.)

  • Water Distillation

    This is most effective for delicate flowers or plants that would otherwise clump together when introduced to steam.

    The Process:

  • The plant is placed into a Still submerged into water.
  • Heat is externally introduced forcing the water to boil. Full water submersion protects the essential oil from overheating.
  • Once at the appropriate temperature the water is sent through a Condenser. The Condenser is encased in cold water same as before.  
  • The hydrosol separates from the oil allowing it to be syphoned off and used as essential oil.

  • Water and Steam Distillation

    Just as it sounds it is a merge of the two previous distillation processes.

    The Process:

  • The plant is placed into a Still, submerged under water.
  • Heat is externally introduced causing the water to boil.
  • Once boiling it begins to produce plant infused to vapor.
  • The vapor is then sent through a Condenser. The Condenser is encased in cold water, which forces the vapor to turn back into a liquid.
  • Once in liquid form it travels to a Separator, where the hydrosol and essential oils separate and the oil is siphoned off.

  • COLD-PRESS (EXPRESSION)

    Or also known as Expression. This method is mainly used for citrus fruits (peels to be specific). All the yummy nutrients that we find in citrus can be found in the peel, and lets face it its rare you see someone munch down on a peel.

    Try Something New: Next time you cut up a lemon, make yourself a wedge, peel and pulp included, close your eyes, pop it in your mouth and chew. Surprisingly sweet!

    The Process:

    • The whole fruit is placed into a machine that pierces/blends the fruit. This breaks open the oil sacs found on the underside of the peel.
    • The mangled fruit bodies are then rotated into a chamber where it is then pressed and squeezed. Forcing out all the juice and oil.
    • Next, the liquids are sent into a filter to separate the remaining solid fruit particles from the liquids.
    • Finally all liquids are sent into a separator where the oils will separate from the juice and eventually siphoned off.

    SOLVENT EXTRACTIONS

    The umbrella of solvent extraction includes Hypercritical CO2 Extraction, Maceration and Enfleurage. Solvent extractions are processes that use food grade solvents (solvent: a liquid or gas that dissolves a solid, liquid, or gaseous solute, resulting in a solution) to isolate the essential oil components from the desired plant. This process is best used for plants that have high resin properties, produce low amounts of essential oil, or are extremely delicate matter that is unable to withstand the pressure of steam distillation. This method can also extract the wax and pigments. When a plant is treated with the solvent, it creates a compound referred to a “concrete”. It must be mixed with alcohol to release the essential oil.

    Hypercritical Co2 Extraction

    This method is one of the newer ones and more expensive than the rest. It produces a higher quality oil, and since heat is not introduced you are getting oil closest to the plants natural compounds. CO2 extraction gives you a closer chemical composition of the original plant for a couple of reasons. One, CO2 is a gas that plants naturally prosper from and not to mention we as beings exhale this gas. Secondly, it doesn’t heat the plant as much as distillation, so you are not getting heat degradation. Frankincense for example, when extracted with CO2 you get immune enhancing properties that are less prominent in a distilled essential oil. The downside to this method is that if there are pesticides used on the plants then this method will yield a higher ratio of those pesticides as well. So, if you plan on purchasing CO2 extractions I’d recommend searching for an organic source. Frankincense, ginger, German chamomile, and calendula are a few of the readily available CO2 extracts on the market today.

    The Process:

    • Pressurized carbon dioxide (CO2) becomes liquid while technically still in a gaseous state, this makes it “supercritical”. In this supercritical state, it is pumped into a chamber filled with the desired plant matter.
    • The liquid properties of the gas act as a solvent, isolating the oils, pigment, resin etc. from the plant matter. This essential oil content dissolves into the liquid carbon dioxide.
    • Once this process is complete the pressure is released forcing the carbon dioxide to turn back into its gaseous state, the liquid it leaves behind is the essential oil/CO2 Extract. In some cases, it’s referred to as CO2 extract even though the consistency is similar to an essential oil.

    Maceration

    These oils are created when carrier oils are used as solvents to extract the plant’s essence. In some cases, this can be a better method because it can capture heavier, larger plant molecules. These oils are also referred to as infused oils since it is part carrier oil. Highly known carrier oils are coconut, sweet almond (not bitter, bitter almond is considered toxic), and jojoba there are many more but these are just the top tier due to their delicate properties. When infusing with the carrier, you want your plant material to be as dry, no dew, but still alive, not dried out. Dewy/wet plant material will inspire bacterial growth and will ruin your batch of oil.

    The Process:

    • Finely chop, grind or crush your desired plant into a powder depending on the plant you may end up with a grittier powder.
    • Place the plant powder and carrier oil into a closed container.
    • Occasionally shaking, leave this mixture to bond together for one week.
    • Once your week is complete strain the liquid.
    • The solid residue pieces are pressed to ensure all the liquid has been collected from the plant particles.
    • The original strained liquid and newly pressed liquid are then mixed together.
    • Finally clarify your liquids through a final filtration process.

    Enfleurage

    Now this method is process of extracting a plants essence through animal fat, or vegetable fat. It is particularly used for creating perfumes. This ancient method was originally used to extract the beautiful floral scents from delicate flowers. Enfleurage was widely known throughout perfumeries in Grasse, a Commune in France. It is still one of the best ways to extract the purest scents but is rarely utilized due to how tedious and time consuming it can be.

    The Process:

    • First take a purified and odorless fat (animal or vegetable) and spread it evenly across framed glass plates and allow it to set.
    • Next take your freshly picked flowers and place them open side down (the pollen center down) into the fat and gently press in. The quality of flower will affect this process. You want fresh, recently picked. Also, try not to get dewy flowers; you don’t want them to go rancid. They need to be dry but not dried out. Another note is that the time of day that they are picked will also affect the scent. Early morning flowers tend to be at their peak fragrance.
    • Depending on the flower, you let them sit in the fat anywhere from 1-3 days or as long as 2 weeks. It is solely dependent on what flower you are using.
    • Remove the depleted petals and reset new ones (onto the same fat). Repeat this process until the fat reaches your desired saturation.
    • Finally once you are happy with the saturation the fat is washed with alcohol to separate the extract from the remaining fat. Once the alcohol evaporates from the mixture you are left with the fragrant extract. In this case it is categorized as an Absolute and not specifically an essential oil. Although in some cases these extracts are put into the essential oil category.