EXTRACTION OF OILS
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Transcript of EXTRACTION OF OILS
Essential oil
What is an essential oil?
Essential oils are volatile (quickly evaporating) aromatic fluids extracted from plants through steam distillation, or in the case of citrus fruits through expression (or cold pressing) of the rind to obtain an oil that retains a juicy, fresh fruit scent.
These “oils” are found in tiny sacs or globules within the plant, are highly aromatic, and although referred to as oils, are not fats.
Essential oils can be extracted from the leaves, stems, roots, bark, flower or resin from a wide variety of botanicals, and can be used for fragrance as well as for their therapeutic benefits.
Extraction of essential oils Various extraction methods are
used in the manufacture and extraction of essential oils, and the method used is normally dependant on what type of botanical material is being used.
EXTRACTION METHODS
Extraction Methods Distillation & Extraction Absolutes CO2 Extracts Organic Extracts Resins
EXTRACTION METHODS Although steam distillation is the most
well-known technique for extracting essential oil from plants, there are several other methods that are used to remove and concentrate the aromatic constituents from plant materials.
Here is a brief description of each method and their influence on the aromatherapeutic properties and fragrance of the oil.
Distillation & Extraction
ESSENTIAL OILSDISTILLATION & EXPRESSION Essential oils are produced in the cells of
aromatic plants and are held in specialized glands.
They are released from the plant and collected (concentrated) most often through steam distillation (and sometimes hydro or water distillation or a combination thereof).
Distillation is a method of separating components based on differences in volatile constituents in a heated mixture.
Steam distillation involves bubbling steam through the plant material.
The temperature of steam is easy to control, making it ideal for heat-sensitive essential oils.
The essential oils contained in plants are immiscible in water and have a higher boiling point, allowing the essential oil to vaporize at a lower temperature than it normally would on its own.
Other methods used to create pure essential oils are dry or vacuum distillation, dry/destructive distillation, and expression (for citrus peels).
Expression, also referred to as “cold pressed”, is a method where oil is obtained by using high mechanical pressure to literally squeeze the oil from the plant material.
Essential OilsDistillation & Expression
WHAT IS AN ABSOLUTE?Like essential oils, absolutes come from
volatile, aromatic fluids extracted from plants.
Delicate flowers such as rose, jasmine and orange blossom are oftentimes extracted as absolutes to yield a higher percentage of oil without using the heat that can damage the petals during steam distillation.
Absolutes differ from essential oils in that they contain a higher density of colorants, waxes and other constituents from the plant, making the aroma highly concentrated and more true to nature.
They are solvent extracted, and since a trace amount of solvent may be present they are not used for therapeutic purposes, but instead, for natural perfumery.
ABSOLUTES: SOLVENT EXTRACTION Absolutes are highly concentrated aromatic oils
extracted from plants using a solvent method. The multi-step process includes first extracting the
aromatic oil from the plant material with a solvent such as hexane.
After the hexane is removed what is left behind is a waxy substance called a concrete.
The aromatic oils are then extracted from the concrete with ethyl alcohol, and after the ethyl alcohol is removed, the remaining substance is an absolute – an oil with an aroma close to the plant from which it came.
An absolute is the most concentrated form of fragrance and highly regarded in natural perfumery.
Absolutes differ from essential oils in that they contain not only essential oil, but also a higher density of coloring, waxes and other constituents from the plant.
In addition, they usually contain a small percentage of alcohol remaining from the second phase of the extraction process (typically up to 2 or 3 percent).
WHAT IS A CO2 EXTRACT? Although the method of extraction is similar
to an absolute, CO2 extracts are more comparable to essential oils in that they contain a myriad of therapeutic benefits without any trace of solvent left behind.
Instead of hexane, they are extracted using CO2 (carbon dioxide) gas under pressure at ambient temperatures.
Under normal atmospheric conditions CO2 is a gas, but in the presence of high pressure it is compressed until it has the density of a liquid and becomes “supercritical” carbon dioxide – neither a gas nor a liquid.
It is while in this supercritical phase that CO2 acts as a “solvent” to extract aromatic oil from plants.
The beauty of CO2 extraction is that once the oil is extracted from the plant material, the CO2 is simply returned to its gaseous state and quickly and completely dissipates.
The advantage of CO2 extraction over steam distillation is that since there is very low heat during the process a greater amount of valuable constituents can be retained.
Typically, they have an aroma closer to the natural plant, especially those oils with spicy notes.
Although there are some advantages of CO2 extraction over steam distillation, there are oils, such as Patchouli, where steam distillation produces a richer, more full-bodied oil.
What is a CO2 Extract?
CO2 EXTRACTS: SOLVENT EXTRACTION
CO2 EXTRACTS: SOLVENT EXTRACTION
CO2 extracts display some of the characteristics of both essential oils and absolutes.
Like essential oils, they contain many beneficial therapeutic properties. But unlike absolutes, they are not solvent extracted.
Instead of using a solvent like hexane, they are extracted using CO2 (carbon dioxide) gas under pressure at ambient temperature.
Under normal atmospheric conditions CO2 is a gas, but when highly compressed it becomes supercritical – neither a gas nor a liquid.
Supercritical CO2 is an excellent organic solvent that can be used to extract aromatic oils from plants.
The beauty of CO2 extraction is that once the oil is extracted from the plant material, the CO2 returns to its gaseous state by lowering its pressure, allowing the gas to quickly and completely dissipate.
Depending on the pressure used, a “select” or “total” extract will result.
Select extracts are created at lower pressures, and are more similar to essential oils in that they are usually fully mobile liquids, and essential oil constituents make up the vast majority of the extract.
CO2 EXTRACTS: SOLVENT EXTRACTION Total extracts are created using higher pressures and
contain more constituents of the plant, can be thicker or waxier, and more closely resemble the constituents of the whole plant rather than just the essential oil fraction of the plant.
Because of the purity of CO2 extracts and since they display some very favorable characteristics not found in essential oils, CO2 extracts are primarily used by the food, body care, and herbal industries, yet CO2 extracts are also excellent for aromatherapy and natural perfumery.
This extraction technique (more accurately called supercritical CO2 extraction) is a relatively new and expensive technology that is more efficient in some ways than steam distillation, because the process has the ability to capture a broader spectrum of the plant components, giving a fragrance more true to the original plant material without the use of chemical solvents.
Other benefits are that the extraction process happens at lower temperatures than steam distillation and that carbon dioxide is nontoxic, odorless, and is easily removed from the extracted oil at the end of the process.
Organic Extracts
WHAT IS AN ORGANIC EXTRACT? Organic extracts are made using modernized technology similar to the ancient method of enfleurage. The extraction process uses only certified organic solvents such as fixed oils and alcohol to coax the aromatic essence out of the plant material. The resulting bio-available essence, extracted without added heat, captures the intricate aroma of the original plant material.
ORGANIC EXTRACTS Rose, Jasmine, Carnation, Orange Blossom,
and Tuberose. These oils are best used for body care and
aromatherapy due to the ‘aliveness’ of the essences.
However, natural perfumers who wish to create organic perfumes will also love these oils.
This new technology, for the first time allows Jasmine oil to be used for true aromatherapy purposes, whereas previously it had only been available as an absolute and therefore had not been recommended for therapeutic applications.
Resins
RESINS & OTHER TYPES OF “OILS” We carry a few other types of natural aromatic oils that
have been extracted using other processes. These include natural exudates and resins (or resinoids). These aromatic essences are collected from the resin
that oozes out of the bark of trees when the trees are tapped (like rubber trees or maple trees [for maple syrup]).
Another type of aromatic oil we offer comes from the traditional destructive distillation method that gives rise to Fossilized Amber Oil.
In destructive distillation, the starting material (such as Benzoin resin) is super-heated and cooked until an oil substance is obtained from the solid starting material.
Thus, oil can be obtained from something that didn’t really have oil in it in the first place.
CONCLUSION
