While essential oils, CO2 Extracts, and absolutes are all considered aromatic extracts, what makes them unique is their method of extraction and the resulting chemical composition of each type of extraction.
Essential Oil
Essential oil is a liquid aromatic extract that usually is steam-distilled out of different parts of aromatic plants. The resulting extract contains only the specific and unique aromatic molecules, and nothing else.
The aroma we smell from aromatic plants is made up of a complex array of molecules that are highly volatile, and fleeting. To capture the aroma and produce essential oil, the fragrant plant material, from seeds, roots, flowers, leaves, needles, cones, resins, or wood, is gathered and placed in a distillation apparatus, where steam is introduced and gently draws out the ephemeral molecules and transforms them into a physical liquid extract – the essential oil. Read More: Steam Distillation Process
Cold pressed: This extraction method is specific only to citrus fruits and literally squeezes out the essential oil compounds from the peel of fruits like lemons, limes, grapefruits, tangerines, and oranges. Read More: Cold Pressed Process
CO2 extracts
Supercritical Fluid Extraction (SFE) is the process of separating one component (the extractant) from another (the matrix) using supercritical fluids as the extracting solvent. More than 90% of all analytical supercritical fluid extraction (SFE) is performed with carbon dioxide (CO2). Apart from having relatively low critical pressure (74 bars) and temperature (32Co), CO2 is relatively non-toxic, nonflammable, noncorrosive, and safe.
CO2 Extraction Process
When CO2 is used in essential oil extraction, will add CO2 in a chamber that includes plant material and use the exact amounts of pressure and temperature needed for CO2 to reach its supercritical state, we called this CO2 gas a supercritical CO2 fluid, its gas properties allow it to effuse through all plant matter, while its liquid properties allow it to extract compounds efficiently.
At this point, and with the help of some additional heat, CO2 acts as a solvent and causes the plant material to separate, carrying with it all the essential compounds. Once done, CO2 is separated from the organic compounds and left with full-spectrum essential oil.
CO2 Extract
CO2 Supercritical Extracts are also referred to as CO2 Extracts, they are produced by using a method known as supercritical carbon dioxide extraction. CO2 extracts display some of the characteristics of both essential oils and absolutes. Like essential oils, they contain many beneficial properties. But unlike absolutes, they are not solvent extracted. Instead of hexane, they are extracted using CO2 (carbon dioxide) gas under pressure at ambient temperatures.
- Total Extract: Contains all the possible CO2-extracted components from the plant material, these are often very thick and aromatic and can have between 3% – 50% of essential oil compounds, with the remaining extract being composed of waxes, lipids, and it will be depending on the plant material.
- Select Extract: Contain mostly the essential oil components, which can make up 35% to 95% of the extract. Select extracts are not viscous like total extracts and hence are easier to use.
The beauty of the CO2 extraction process is that when you adjust the temperature and pressure of the supercritical CO2 fluid, you get different extracts; especially in the separation vessel using a special device we call a cold trap, which A higher temperature setting will allow us to get more terpenes, that is, the special natural aroma of plants, such as cannabis terpenes, which will allow users to obtain more entourage effects.
The adjustment of extraction temperature and the application of a cold trap broke an old-fashioned understanding: supercritical CO2 extraction will lose the terpenes of plants. Read More: Terpenes: A False Fact About CO2 Extraction Vs. Cold Press Extraction
Absolute oil
- Definition: Absolutes are highly concentrated aromatic oils extracted from plants using a solvent method; Solvent extraction uses solvents, specific petrochemicals like hexane, to pull out the fat-soluble aromatic compounds of the plant.
- Questions: why use solvent not steam distillation? Because those aromatics from plant materials are too delicate to be exposed to steam.
Absolute Oil Extraction Process
Solvent extraction also pulls out other types of compounds from the plant like pigments and waxes – making the resulting extract thicker and more viscous and deeper in color, so the solvent extraction process needs a multi-step process.
- Step 1# Solvent extraction: Extract the aromatic oil from the plant material with a chemical solvent such as hexane.
- Step 2# Remove petrochemicals solvent: After the solvent such as specific petrochemicals like hexane is removed what is left behind is a waxy substance called concrete.
- Step 3# Ethyl alcohol extract: The aromatic oils are then extracted from the concrete with ethyl alcohol
- Step 4# Get the absolute oil: 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.
Additional processing creates the finished extract called an absolute oil, it is the most concentrated form of fragrance and is highly regarded in natural perfumery.
Absolute Oil and CO2 Extracts and Essential oil
- The Difference Between Absolutes Oils and Essential Oils: 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).
- The Difference Between Absolutes and CO2 Extracts: Absolutes are typically solvents extracted using hexane as the solvent. Trace amounts of the hexane may remain in the final absolute. However, 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 by lowering its pressure, allowing the gas to quickly and completely dissipate, it eliminates the risk of trace amounts of chemical solvents remaining in the finished extract.
- The Difference Between CO2 extracts and Essential Oils: CO2 extracts are more concentrated. Both co2 extracts and essential oils are potent, but co2 extracts tend to be more potent and have a longer shelf life. CO2 extracts are also less likely to cause skin irritation, making them a good choice for people with sensitive skin.
CO2 Extract vs. Absolute Oil
The CO2 extract obtained from the rhizomes of some plants, such as vanilla, and ginger, through a supercritical CO2 extraction process under low pressure (less than 150bar), is a pure essential oil, which is very pure compared to absolute oil, and does not contain chlorophyll, wax, high-Density pigments, and other plant components do not require post-processing; but the entire CO2 extraction process will take a relatively long time.
But when biomass is extracted under high-pressure supercritical CO2 fluid (greater than 150bar or even as high as 350bar), the CO2 extract is a viscous extract, which contains all imaginable substances in plants-chlorophyll, wax, high-density pigments, and others; for example, the CO2 extraction of ginger uses a pressure greater than 180bar, and a lot of depressing pigments will be obtained. It will take a long time to clean the pipeline of the CO2 extraction machine to remove these disgusting pigments. time.
Summary: Extracting some biomass such as ginger under the correct CO2 extraction process, the resulting CO2 extract is an essential oil that is purer than absolute oil. The CO2 extract obtained by extracting certain biomass under a high-pressure CO2 extraction process contains more invalid substances than raw absolute oil but does not have alcohol.
CO2 extracts vs. Essential oils
Most of the essential oils on the market are obtained through a high-temperature steam extraction process, while the CO2 extraction process is based on room temperature, so the CO2 extraction retains more original terpenes of plants – the aroma of natural herbs, spices, or plants source.
The amount of plant natural compounds in the essential oil obtained by steam distillation will be significantly lower than that of CO2 extract, about 50% higher, which is also determined by the nature of the extraction process, so when more raw materials are needed in the extract, CO2 extracts are more useful than essential oils.
In conclusion:
CO2 extracts contain more terpenes (natural herbal, spice, or botanical aromas) than essential oils;
CO2 extracts contain more natural compounds than essential oils.
Further reading: Terpenes are generally colorless liquids that are lighter than water and have an aroma. In nature, terpenes widely exist in plants and emit into the atmosphere. The most common ones are pinene (ie pinene, the main component in pine and turpentine oil), limonene (ie 1,8-terpene diene, present in citrus and pine leaves), hemiterpene (ie isoprene, present in cottonwood, eucalyptus, oak, and white spruce), etc.
Read More: CO2 Extraction vs Cold Pressed
Diffs Between CO2 Extract and Essential oil Of 7 Plants
Angelica Root CO2 Extract vs Angelica Root Essential Oil
CO2 extract of angelica root is different from the steam-distilled angelica essential oil.
- Angelica CO2 extract smells exactly like the original herb itself, with darker reddish-brown, and thicker viscosity.
- Angelica essential oil smells more perfume-like and it’s volatile and watery, light brown, and overall less potent.
Angelica root CO2 extract contains unique and heavier molecules of angelica root that cannot be extracted by steam distillation. By CO2 extraction process, will reap the complete benefits of the whole angelica roots itself.
Allspice CO2 Extract vs Allspice Essential Oil
Allspice berry CO2 extract has a sweeter, rounded full-bodied aroma and is deeper brown compared to Allspice berry essential oil. CO2 extracts contain unique and heavier molecules that cannot be extracted by steam distillation.
AllspiceCO2 Extract vs Allspice Essential Oil
Allspice berry CO2 extract has a sweeter, rounded full-bodied aroma and is deeper brown compared to Allspice berry essential oil. CO2 extracts contain unique and heavier molecules that cannot be extracted by steam distillation.
Frankincense CO2 Extract vs Frankincense Essential Oil
The two different extraction processes result in oils with different aromas, colors, and consistency.
- Frankincense CO2 extract’s aroma is resinous, earthy, grounding, and warm with terpenic, green notes. The aroma of frankincense CO2 extract is a lot stronger and deeper than its frankincense essential oil. Most importantly, Frankincense ethereal/essential oil does not contain Boswellic acids as the process of steam distillation is unable to extract these heavier molecular compounds. Only via supercritical CO2 extraction is able to extract this precious unique active phyto-compound of Boswellia Serrata.
- Frankincense essential oil is greener and sharper, The frankincense essential oil contains more alpha-pinene and alpha-thujene than its CO2 counterpart. The essential oil also withholds around the same percentage of limonene and far less incensole and incensole acetate than the CO2.
Vanilla CO2 Extract vs Vanilla Oleoresin
- Vanilla CO2 has a chemistry closer to the Vanilla plant, making it highly desirable for its sweet, rich aroma.
- Vanilla oleoresin has a sweet, creamy aroma that’s still quite pleasant, but lacks the depth of the CO2.
- The vanilla extract oils component is vanillin. High-quality Vanilla CO2 contains a lesser amount of vanillin, between 10-13%, like Vanilla beans – and the essential oil contains a much higher amount – around 75-85%.
Arnica Flower CO2 Extract vs Arnica Oil
Most of the commercial arnica oils out in the market are infused arnica oil (dried or fresh arnica flowers macerated in a carrier oil base).
Arnica flower CO2 extract is a slow-moving viscous liquid and has a more bitter aroma, and is deeper brown in color compared to infused arnica oil which is yellow in color and of natural liquidy oil consistency. Infused oils are the weakest but the safest form of oil extraction as the properties of arnica flowers are extremely mild. CO2 extracts contain almost the full range of active ingredients that cannot be extracted by the infusion method.
Lavender CO2 Extract vs Lavender Essential Oil
Lavender CO2 Extract its has own unique compound lavandulol, which is found in abundance in the lab analysis of CO2 extract but almost zero in its essential oil.
The color of the lavender CO2 extract is champagne golden and thicker in consistency, unlike its lavender essential oil counterpart which is watery and clear in liquid. The process of supercritical CO2 extraction uses liquid CO2 to extract the most out of each plant, therefore resulting in the best grade with no form of oxidation and heat degradation of the final product.
Works Cited: Absolutes and Concrète for Natural Perfumery Essential Oils? Absolutes? CO2 Extracts? Is one Better?