Distillation is an ancient process that separates mixtures by using the relative boiling points of two substances. Two liquids having a boiling point difference of 25 degree Celsius or more are usually well separated by distillation. In the case of substances that are non-volatile in nature, distillation is used to separate a liquid from that compound by using the property of viscosity.
Basic principle: heating a mixture till the boiling point of volatile compounds and vapors or gas produced by this process are collected back by condensation.
Steam Distillation of Essential Oil
Steam distillation is the most common way you can extract essential oil from plant matter, a process that isolates the aromatic, volatile element of the plant with steam. This technique of oil extraction is the main method used in the fragrance and essential oil industry because it has the advantage of being the most efficient.
Steam Distillation Process
First, plant matter is introduced in a distillation tank. With the use of water and heat, the produced steam carries oils to the top of the tank, and it is then passed through a condenser, resulting in a mix of water and oil. The mix then goes through further distillation to separate water and oil, collect the condensed water and oil droplets and channel them through a filter, which separates the water from the oil, and the result is essential oil.
Cons
While this essential oil extraction process is much simpler, there are some downfalls. It is more prone to error, much less efficient, and may potentially damage part of the essential oil profile of the plant.
- Selectivity: Steam distillation is a less selective method than CO2 extraction and can extract a wide range of compounds from plant material, including those that may not be desired. This can result in a lower yield of the desired compounds and a product that is less pure.
- Efficiency: Steam distillation is a less efficient method than CO2 extraction and can extract less of the desired compounds from a given amount of plant material. This can result in a lower yield of essential oils and other plant compounds, which can make the production of these products less cost-effective.
- Purity: Steam distillation can leave behind residual solvents or contaminants, especially if the equipment is not properly cleaned and maintained. This can result in a product that is less pure and may not meet the purity standards required for use in the food, cosmetic, and pharmaceutical industries.
- Limited range of compounds: Steam distillation is limited in the range of compounds it can extract from plant materials. It is primarily used to extract essential oils and some terpenes but is not effective at extracting other compounds such as cannabinoids and flavonoids.
Pros
- Easy Control: Steam distillation allows you to control the temperature and amount of steam you apply to the plant material. Keeping the temperature right at the boiling point of water allows for the least amount of degradation to delicate botanical oils.
- Wide Application: Steam distillation is useful for extracting most fats, oils, and waxes.
- Natural: Steam distillation is a natural method that does not require the use of any solvents or chemicals. This makes it a preferred method for producing organic and natural essential oils and other plant compounds.
- Cost: Steam distillation is a relatively inexpensive method that does not require expensive equipment. This makes it more accessible to small producers who may not have the resources to invest in the necessary equipment and training.
- Accessibility: Steam distillation is a simple method that can be easily performed by small producers. This makes it accessible to a wider range of producers who may not have the technical expertise to perform more complex extraction methods.
CO2 extraction
Supercritical CO2 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.
Essential oils derived from the supercritical CO2 extraction of herbs are similar to the oils produced through distillation in that they can be used in aromatherapy and natural perfumery.
CO2 Extraction Process
When CO2 is used in essential oil extraction, will add CO2 in a chamber of a supercritical CO2 extraction machine that includes plant material and uses 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.
Pros
- Selectivity: CO2 extraction is a selective method that allows producers to extract specific compounds from a plant material while leaving others behind. This makes it possible to produce a purer product with a higher concentration of the desired compounds.
- Efficiency: CO2 extraction is a more efficient method than steam distillation and can extract more of the desired compounds from a given amount of plant material. This makes it possible to produce a higher yield of essential oils and other plant compounds.
- Purity: CO2 extraction produces a purer product than steam distillation, as it does not leave behind any residual solvents or contaminants. This makes it a preferred method for producing high-quality essential oils and other plant compounds for use in the food, cosmetic, and pharmaceutical industries.
- Versatility: CO2 extraction can be used to extract a wide range of plant compounds, including essential oils, terpenes, cannabinoids, and flavonoids. This makes it a versatile method that can be used to produce a wide range of products.
Cons
- Cost: CO2 extraction requires expensive equipment and technical expertise, which can be a barrier to entry for small producers. The cost of the equipment and the high pressure and temperature required to operate the equipment can also result in higher production costs.
- Complexity: CO2 extraction is a complex method that requires specialized equipment and expertise. This makes it less accessible to small producers who may not have the resources to invest in the necessary equipment and training.
While it requires qualified personnel and there are higher costs associated with the equipment needed for supercritical CO2 extraction, it is by far the most efficient and quickest method to cold extract CBD. It is also environmentally friendly due to the limited amount of emissions, and safer than extractions that use certain solvents as CO2 is “generally regarded as safe”.
CO2 extraction vs steam distillation
Advantages and Disadvantages of Distillation Versus CO2 Extraction
Four pros of CO2 extraction over the steam distillation
- CO2 extraction of Essential Oils usually happens at a lower temperature than in the case of Steam Distillation, so many of the active constituents don’t die, and they remain at the same temperature. The supercritical CO2 extraction process operates at temperatures between 95 to 100 degrees F whereas steam distillation operates at temperatures between 140 to 212 degrees F.
- The CO2 extraction process might produce higher-quality oils that have not been altered by the application of high heat, unlike the steam distillation process. In CO2 extraction, none of the constituents of the oil are damaged by heat.
- CO2 extracts are usually thicker than their essential oil counterparts and often give off more of the aroma of the natural herb, spice, or plant than a distilled essential oil.
- Co2 extracts are said to be more useful for purposes when more of the constituents of the raw material is needed in the extract and like in the flavor industry etc.
Four cons of CO2 extraction less the steam distillation
- The equipment, set up and operational cost of CO2 Extraction Essential Oils is costlier than normal essential oil.
- CO2 Extraction Essential oils are more expensive than steam-distilled essential oils due to the process of distillation due to expensive machinery costs.
- The process of extraction of CO2 Extraction Essential Oils is more complex than steam-distilled oils and the technical skills required to distill CO2 Extraction Essential Oils in higher than required for normal Essential Oils distillation.
- CO2 Extraction Essential Oils are usually processed at a slower speed than normal essential oils.
CO2 extraction and steam distillation are two common methods used for extracting essential oils from plant materials.
Top 5 Differences Between the CO2 Extraction and Steam Distillation
- Solvent: CO2 extraction uses carbon dioxide as a solvent, while steam distillation uses water and steam.
- Pressure: CO2 extraction requires high pressure, while steam distillation relies on heat and pressure.
- Temperature: CO2 extraction is typically performed at a lower temperature than steam distillation, which can help preserve heat-sensitive compounds.
- Efficiency: CO2 extraction can be more efficient than steam distillation for certain plant materials, such as those containing high concentrations of volatile compounds.
- Purity: CO2 extraction can produce extracts with higher purity and specificity, as it can be fine-tuned to target specific compounds. Steam distillation produces a more generalized extract.
CO2 extraction is ideal for producing high-purity, concentrated extracts, while steam distillation is often preferred for producing more complex, less concentrated extracts that retain the characteristic aroma and flavor of the plant material.
O2 Extraction and Steam Distillation: Which method is better?
The answer to this question depends on the type of plant material being extracted and the desired end product. CO2 extraction is a more efficient and selective method that can produce a higher yield of pure essential oils and other plant compounds. It is also more versatile, as it can extract a wider range of compounds from plant materials.
Steam distillation, on the other hand, is a simpler and more natural method that is more accessible to small producers. It is a preferred method for producing organic and natural essential oils and other plant compounds. However, it is less efficient and less selective than CO2 extraction, and is limited in the range of compounds it can extract.
In some cases, a combination of both methods may be used to extract the desired compounds. For example, steam distillation may be used to extract the essential oils from a plant material, while CO2 extraction may be used to extract other compounds such as cannabinoids or flavonoids.
CO2 Extraction and Steam Distillation of Terpenes
Terpenes(Hydrocarbons), is evident in nearly all Essential Oils.
: Terpenes are a large and diverse class of organic compounds, produced by a variety of plants, particularly conifers and as well, Cannabis sativa plants. Comprised of Hydrocarbons, Terpenes are found in most oils and include Monoterpenes and Sesquiterpenes. Pinene and Limonene are the two most common of all constituents that make up Essential Oils.
Terpenes are mainly extracted from biomass (such as cannabis) in two ways. They can be CO2 extracted or steam-distilled. Both methods capture volatile oils (i.e. essential oils), which are complex mixtures of low-boiling compounds composed mainly of low-molecular-weight terpenes.
Steam distillation produces higher concentrations of hydrocarbon terpenes such as myrcene and beta-caryophyllene. Additionally, steam distillation can be done with fresh plants, rather than dried ones. Extraction can take place in the field, which avoids having to transport plant material for processing. Steam distillation is very easy and cheap to perform on a large scale and often produces very high-purity terpenes, but with little to no cannabinoid content.
CO2-extracted terpenes have a much higher mass upper limit than steam distillation. In the subcritical stage, carbon dioxide is more selective for low molecular weight components, similar to steam distillation. Supercritical co2 can extract larger molecular weight components and can able to capture a larger spectrum of components, such as cannabinoids, lipids, and potentially flavonoids. CO2 captures a wider variety of oxygenated terpenes such as nerol and eucalyptol.
Works Cited: Understanding CO2 Extracted Essential Oils – Pros & Cons CBD Extraction: CO2, Steam Distillation, and More