Humans have used various ways of extracting active compounds from herbs, like soaking them in water, alcohol, or oils. Further, many would heat the oil or boil the water to get more herbal compounds. However, these traditional extraction methods had numerous limitations. On the contrary, the CO2 supercritical process is a highly efficient way of extracting herbal bioactive compounds.
Each liquid has different physical properties and is only suitable for extracting certain types of extracts from specific herbs. Moreover, these traditional methods produced highly crude extract and thus often needed further complex processing. Even then, there was limited control over the extraction methods, meaning that large amounts of active or essential compounds were lost, and numerous unneeded impurities were introduced.
In modern times, these methods are still used, but by deploying complex equipment. Further, researchers discovered that using gases for extraction has some unique benefits. Modern technology allows liquifying the gases even at room temperatures. Moreover, by altering the pressure and temperature, the same gas would display different properties as a solvent. Thus, helping extract a broad spectrum of compounds. Using various pressures also allows extracting multiple extracts from the same herbal source.
Moreover, at the end of the extraction process, gas will readily escape when temperature and pressure are raised without leaving any residues (unlike liquid solvents) behind. Moreover, gases are also cleaner and lack impurities, whereas most liquid solvents would have some amounts of contaminants.
CO2 supercritical extraction is preferred among various gases, as it is safer and easier to handle than other gases. Further, it has some unique properties, making it an excellent solvent at specific temperatures and pressures.
Process of CO2 Extraction Overview
Supercritical CO2 extraction is the most common way of extracting cannabis extract or CBD and various other herbal extracts. CO2 is preferred over other gases due to its safety profile and ease of handling, but more importantly, it does not leave a residue. Thus, it is used to extract various bioactive compounds.
Supercritical is a unique state of matter. Everyone knows that most compounds may exist as liquid, solid, or gas, depending on the storage temperature and pressure. Thus, under pressure, gas may become liquid. Further, increasing the pressure and lowering the temperature may even covert gases to solids.
For creating supercritical fluids, one increases pressure without lowering the temperature much. Gas is pressurized at temperatures, where it would generally be in a gaseous state. However, high pressure forces it to achieve a state between gas and liquid (refer to Table 1). It reaches a cloud-like state. In this state, it is a highly penetrating solvent with extremely low viscosity and surface tension. Further, this supercritical mass of gas can be altered by changing pressure and temperature.
Studies show that CO2, a gas at room temperature, may be converted to supercritical mass at temperatures above 31.2 degrees Celsius and pressure above 7.3 MPa. However, the choice of temperature and pressure would differ for other gases.
Figure 1 supercritical CO2 (Image source: 1. Capuzzo A, Maffei ME, Occhipinti A. Supercritical Fluid Extraction of Plant Flavors and Fragrances. Molecules. 2013;18(6):7194-7238. doi:10.3390/molecules18067194)
Supercritical Carbon dioxide
Once this supercritical stage is reached, it may be further altered to control its physical and solvent properties. Thus, one may increase temperature or pressure or alter its flow rate. It means that by changing the pressure or even temperature, one may extract different bioactive compounds from the plants. Of course, these alterations can be done manually. However, many automated machines would allow doing this at the touch of a screen, thus allowing to extract a range of bioactive compounds from any given plant. Therefore, it may help manufacturers to create unique products in a short time.
Further, most of the modern and automated systems would be closed loop. It means that after the extraction process, CO2 is recycled and reused.
Can one use the same CO2 machine to extract bioactive compounds from different herbs? Yes, definitely, though one may need to know more about specific parameters like the pressure, temperature, and flow rate to use. Similarly, altering pressure may help control what fraction of any herb, including cannabis, one wants to extract. Thus, cannabinoid extractors may use various regimes to get terpenes, full-spectrum extract, and so on. So, as one can see that CO2 extraction provides lots of flexibility.
Adding solvents to extraction machines
Quite like any other solvent, CO2 also has its downsides. For example, some compounds are insoluble or poorly soluble in CO2. Thus, adding another solvent to these machines solves these problems helping to extract terpenoids, carotenoids, alkaloids, glycosides, polyphenols, and other compounds.
Moreover, since most good equipment would allow changing pressure and temperature, thus it may help target and extract specific compounds.
List of CO2 (Carbon Dioxide) Extraction Equipment
CO2 extraction is not cheap in the short run, but it may readily help recover the cost of equipment in the long run due to its high efficiency and ability to produce quality extracts. Many manufacturers are making CO2 supercritical extraction machines, but few stand out. These are usually manufacturers from North Americas or Europe, where Industrial hemp extraction equipment is most needed.
It is good in a way that it is simple to install, set up. However, the company is more focused on high-volume machines. Thus, this machine can extract up to 200 pounds if used continually. Like many machines in its class, it is fully automated, controlled from a tablet or phone, and built for continuous use.
On the downside, it is relatively expensive and costs above 250k USD. It does not allow adding of solvents, which may have certain downsides and limitations. It is a Canadian company with US and Canadian certification. However, it may lack specific certifications needed to operate such types of machinery in the EU.
It is a company focused mainly on the US market and has numerous machines for every need. Their machines are especially good for subcritical and supercritical extraction. However, they rarely provide the option of adding solvent for the extraction of specific bioactive compounds. Although these machines are highly versatile and can be adapted to various needs, they are generally regarded as overly complex. Even small extraction volume machines are quite complex for their category, meaning issues with maintenance. Despite pros like affordable cost and scalability, they remain complex systems, and these machines also operate at high pressures.
These are a state of art, powerful, fully automated machine from one of the US manufacturers. The machine is highly efficient, relatively easy to set up. However, it is primarily focused on large-scale manufacturers, and thus it may be pretty expensive for small to mid-manufacturers. The base model cost is about half a million USD, and other setup costs may be involved. Though it is an automated solution, it is for experienced professionals, as it still requires a high degree of expertise to operate. If the plans are big, this machine could be an option. However, for small to mid-cap companies, there are many other options, too.
It has numerous models for supercritical extraction with various capacities. Some of these machines are made explicitly for cannabis extraction, like the SFE PROD 2X10L 400 BAR. The company has a high focus on producing machines for pharma and large-scale extract manufacturers. Its machines are made by keeping GMP standards in mind. However, as one can expect, these machines might be pricy and difficult to operate. Therefore, these machines are created by considering that the facility already has some machines and experience in handling complex systems.
Moses is produced in Europe and has all the European certifications. It belongs to the new class of machines called modular machines. Thus, MoSES stands for Modular Supercritical Extraction System. These machines are specifically made by keeping in mind the various requirements of the CBD industry.
Some of the features that make it stand out are:
- Modular design, and thus the ability to expand machines according to business needs.
- Fully automated control.
- Ability to extract various fractions in a single run.
- Faster extraction time, as it operates at increased pressure.
- Flexibility to add polar co-solvents for extracting phenols, terpenoids, and other compounds.
MoSES systems are equally suitable for small to large manufacturing needs, and these machines can be upgraded accordingly. Moreover, these machines are specifically produced for the European market, with all the needed approval.
Further, these machines are also tested for extracting various extracts apart from CBD, providing greater flexibility to manufacturers.
Which CBD/Hemp Products can CO2 Extraction Produce?
CO2 supercritical extraction is generally accepted as one of the best ways of extracting “full-spectrum” hemp extract. The end product is a light-colored paste or resin rich in CBD/CBDA (60-70%). Along with other beneficial compounds like polyphenols, terpenes, and other minor cannabinoids.
Generally, this full-spectrum extract is appreciated by CBD lovers due to its intense flavour and presence of entourage effect.
However, it is vital to understand that one may extract different kinds of CBD extracts by tweaking temperature and pressure settings. Further, one may enrich the extract by adding various solvents. Thus, the quality of the final extract would depend on the specific machine parameters used, along with what solvent was used or wasn’t used.
It means that though these machines are highly automated, they leave room for lots of experimentation so that any producer can come up with a unique end product. Although ethanol is the most commonly used solvent along with CO2 extraction, one may create quite a different end product by using other solvents. Similarly, extraction temperature and pressures have a significant influence on the end product.
One may use this extract for further processing and creating either CBD isolate or broad-spectrum CBD. Generally, this extract would still require to go through processing before making its way to the final product. Thus, winterization and filtration help remove fats, oils, and waxes. Other processes involved in getting CBD isolate are decarboxylation, distillation, and crystallization.
Certifications to Look For
Needless to say, that it would depend on the location of the manufacturing facility, as requirements vary from place to place. Generally, European companies are pretty good at meeting local European and global requirements.
If someone is planning to install a unit in the EU zone, most machines for CO2 extraction should preferably include the EC declaration of conformity. Furthermore, it would include additional certificates for pressure tests, control procedure reports, material certificates, welding specifications, to name a few.
One may ask the manufacturer to provide component conformity, material conformity, leakage test, tank cleaning ability, and other reports as per the requirements.
Many high-quality machinery producers would also produce radiographic weld testing reports to ensure the quality of their products. In addition, the EU also requires pressure testing of the tank as mentioned in the EU Pressure Equipment Directive (PED 2014/68/EU).
For some manufacturers located in less regulated places, many of these certificates may not be needed. However, it is still good to ask for these certificates as the presence of these certificates helps confirm not only the quality of the product but also the presence of quality control measures.
It is vital to understand that though many products may appear to have similar specifications, some are produced using better safety standards. Certifications can only confirm these standards. Many of the mentioned certifications are given by third parties to the manufacturers.
Buying CO2 Extraction Equipment
CBD extraction machine price always remains the prime concern. However, it is good to start by identifying the capacity of the machinery. Understand if a particular machine is made for small to mid-level or large-scale producers. The decision in this respect would be based on the buyer’s needs. Nonetheless, it is also good to know if its capacity is expandable or not, about automation, safety features, installation, and training.
It is also good to look deeper into technical specifications regarding maximum pressure, temperature, and other features.
Also, pay particular attention to additional features like the possibility to use solvents along with CO2 usage. It is also vital to know how much CO2 is recycled. Pay attention to the power usage by the machine, as it is often neglected but may ultimately add to the bills.
Next, inquire about all the safety certifications that any equipment has. It is essential to ensure safe operation, reduce operational costs, and, more importantly, meet regulatory requirements.
Generally, it is a good idea to buy equipment from a company that is good at providing post-sales services. If needed, a company that can help expand production in the future, as having multiple machines from different manufacturers is rarely a good idea.
Additionally, one may inquire about specific needs for machine installing, kind of infrastructure needed, space, ventilation, environmental temperature.
Finally, try to figure out about its about maintenance issues with it, workflow with equipment. It is also good to know about labour requirements and any other expertise needed to run the machine.