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 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.
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.
Easy Control: Steam distillation allows 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.
Cost Benefit: Because the steam temperature can remain at the boiling point of water, requiring less fuel for the steam boiler.
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.
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 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. Read More:Supercritical CO2 Extraction Process: Basics, 7 Advantages, 7 Features, 4 Applications
The most efficient method
CO2 is regarded as generally safe
Quick (once everything is in place)
Expensive (equipment costs)
Needs qualified personnel
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 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”.
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 expensive than the 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 complex than steam distilled oils and 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 the normal essential oils.