What are the Methods of Extracting Essential Oils?Some methods of extracting essential oils have been around for thousands of years while others are still being proven. The section will give you an understanding of the different methods!
There are many different ways to extract essential oils and they are listed below:
- Expressed Oils
- Steam Distillation
- Solvent Extraction
- Fractional Distillation and Percolation
- Carbon Dioxide Extraction
- Phytonic Process
What is Enfleurage?
Enfleurage is one of the oldest methods of extracting essential oils and is rarely used these days because of its high cost. It involves placing the flower petals on a layer of glass that is first spread with a thin layer of fat called"chassis". The volatile oil diffuses into the fat, then the fat is collected and the oil is extracted from the fat using alcohol.
Once the alcohol evaporates what is left behind is called the absolute. As you can imagine, this is a very time consuming process, but it was the only way to extract delicate flowers like Jasmine for a very long time!
What is Expression of Oils?
When oils are taken from the rind of fruits they are called "expressed oils". This method is cold and does not involve any solvents or heat of any kind. Most of the citrus oils are extracted in this manner including grapefruit, lime, orange and lemon essential oils.
These are not technically considered essential oils for this reason, but they are still definitely therapeutic oils. The most important thing to consider with cold pressed oils is the source of the crop since citrus fruits are constantly sprayed with pesticides and it can be very concentrated in the oil!
What is Involved in Steam Distilling Essential Oils?
Steam distillation has been used for hundreds of years and today remains one of the most favorably methods of extracting essential oils. Technically speaking if it not extracted using steam distillation or cold expression it is not a therapeutic grade essential oil.
There are actually three different steam processes that are described further in the distilling section. But in all of the methods, steam is used to rupture the oil membranes in the plant and release the essential oil.
The steam carries the essential oil to a condenser and then as it re-liquefies the lighter essential oil floats on top. The water and oil is then separated and the water portion is referred to as the hydrosol, hydrolat, or flower or floral water. And the oil portion, of course, is the essential oil!
The essential oil distilling equipment including the condenser, separator and cooking chambers can all have an enormous impact on the quality of the oil. As well as, the distillation temperature and pressure! And even if everything appears correct, the process can still produce oils that don't meet the AFNOR Standards. So essential oil distillers must have the knowledge and expertise to know how to produce therapeutic grade essential oils.
What is Solvent Extraction?
Solvent extraction is a method of extracting essential oils that are sold by the perfume industry. And technically does not produce therapeutic grade oils because chemicals such as hexane, acetone, di-methylene-chloride.
Are these the oils that are used in bath oils and gels, candles, shampoos, toothpaste, fly spray, and air fresheners?
These are also the 98% of the oils sold in health food stores, retail outlets and aromatherapy suppliers!
What is Percolation and Fractional Distillation?
Fractional distillation separates the volatile oil in different fractions or portions at various boiling points. This is used in oil refineries for distillation of petroleum products and is not suited for therapeutic grade essential oils.
Percolation is one of the newer methods of extraction essential oils. It is similar to normal distillation but the equipment is literally upside down! It has been used successfully in France; however sometimes an emulsion is produced that can not be separated out, so until it can be further developed you will not see it on a large scale.
What is Super Critical Fluid Extraction? (Carbon Dioxide Extraction)
Super critical fluid extraction or carbon dioxide extraction is also a fairly new solvent extraction process that uses carbon dioxide at very high pressure. The carbon dioxide is injected into the tank where the plant material is contained and acts as a solvent to extract the oil.
The carbon dioxide is colorless and odorless liquid and can be completely removed which is a good thing.
Additionally, the distilling equipment is extremely expensive. So until more is known about this process, it is advised to use only steam distilled and expressed oils!
What is the Phytonic Process?
The Phytonic process is a one of the newest methods of extracting essential oils using non-CFCs (non-chlorofluorocarbons). It is also called Florasol Extraction and the oils are referred to as phytols.
Distilling Essential Oils takes
Expertise and Knowledge!
Distilling essential oils is an art and a science! And most essential oils distillers use methods of extracting essential oils that use solvents or attempt to adulterate the oil prior to distribution.
Honestly, like many things out in our world, the process of distilling can be good for the consumer (and the environment) or not so good, so please take the time to be an educated oil user!
What are the Methods of Extracting Essential Oils?
There are many different ways to extract essential oils. This section will mainly deal with the details and methods of steam distillation.
What is Steam Distillation?
Distilling essential oils by steam distillation can be accomplished three different ways. They are:
- Water Distillation;
- Water/Steam Distillation; and
- Straight Steam.
What is Water Distillation?
This method is where the plant material is placed in boiling water. The steam and oils are captured and then separated out to produce the essential oil. Clove essential oil is collected using water distillation.
What is Water/Steam Distillation?
This method is where steam and water are pushed around and though the plant material. And then the steam and oils are captured and then separated out to produce the essential oil. Nutmeg oil is collected using this method!
What is Straight Steam Distillation Method?
Distilling essential oils using the straight steam method involves pushing steam through the plant material and then picking up the essential oil. Lavender essential oil is distilled in this manner!
How do the Methods Vary?
In all of the methods, steam is used to rupture the oil membranes in the plant and release the essential oil. The steam carries the essential oil to a condenser and then as it re-liquefies the lighter essential oil floats on top.
The water and oil are then separated out, and the water is referred to as the hydrosol or hydrolat, or flower or floral water. And the oil of course is the essential oil!
How Does the Essential Oil Distilling Equipment Affect the Oil?
The size and material of the cooking chamber, the condenser type and the separator all can change the outcome of the oil.
For instance, the cooking chambers that are best are made of non-reactive metal. This minimizes the essential oil from being adulterated (changed) by reactive metals such as copper and aluminum. The best metal that is non-reactive is stainless steel!
Also, vertical steam distillation seems to produce the best quality oil when distilling essential oils. There is no risk of overheating the plant material!
What other Factors Effect Distilling Essential Oils?
They are other factors such as temperature and pressure that affect the quality of oil. For instance, if the pressure or temperature is too high than the oil is changed. It is like over cooking vegtables!
Additionally, the chemical constituents of the oil when over heated become changed or adulterated. The oil pH and polarity can even be completely altered!
So, it has been found that low pressure and low temperature is extremely important to producing therapeutic grade oils. This is how ancient cultures distilled oils for thousands of years!
Can you give the proper pressures and temperatures for Cypress or Tea Tree or Melaleuca Alternifolia Essential Oil?
Sure, here they are!
- Cypress Essential Oil – If we start with 2,000 pounds of material we produce 1 pound of oil. The pressure in pounds must be 0 and the optimal distillation time and temperature is 220 degrees at 24 hours! Anything less, produces oil that has 18 to 20 constituents missing from the oil completely!
- Tea Tree Essential Oil (Melaleuca alternifolia) – If we start with 1,000 pounds of material we produce ten to fifteen pounds of oil. The pressure in pounds must be 3 and the optimal distillation time and temperature is 218 degrees for 2-3 hours.