How CO2 extraction works
- Liquid CO2 is contained in the first chamber (the tank), and the extraction vessel (the second chamber) is filled with hemp plant material.
- The CO2 is heated to the desired temperature to become a tunable solvent, enabling extraction of phytonutrients in the essential oils.
- The CO2 carrying the essential oils is then captured in its supercritical state (gaseous enough to effuse, but fluid enough to dissolve materials)
- The CO2 and oil mixture then flows to the pressure relief valve from the extraction vessel, before reaching the cyclone separator (the third chamber).
- With the reduction in pressure, the CO2 becomes less dense; separating from the CO2.
- The CO2 then recirculates back to the tank through the closed loop system, ensuring the CO2 doesn’t come into contact with external elements.
- The remaining oil droplets from the hemp plant containing CBD are collected for further processing
What is supercritical CO2 extraction?
By ‘supercritical’, we mean the CO2 is prepared for the process at a high temperature & pressure, to extract large molecules and higher yields.
There is also subcritical CO2 extraction (meaning low temperature & pressure), and midcritical, for the degrees of temperature & pressure in between.
Can I learn how to do CO2 extraction at home?
What other extraction methods are there?
A CO2 extraction system doesn’t come cheap, so many will use other equipment to extract CBD Oil from Hemp. Take a look at how the CO2 process compares with the other methods below:
Ethanol extraction is the most common solvent process. Other solvents used include butane, propane, isopropyl, or alcohol.
- More dangerous as it’s a highly flammable liquid
- Dissolves plant waxes for extra nutrients, but this includes chlorophyll which can cause a bitter taste
- Solvent residue can contain toxins, such as petroleum, if not evaporated properly
Olive oil extraction is one of the oldest, cheapest and safest methods.
- Produces a lower yield, so a higher dosage may be required
- Products have to be stored in cool & dark environments as they can perish very quickly.
vs Steam Distillation
Steam distillation is another old extraction process; popular for its low cost and low risk of extracting toxins & other contaminants.
- It’s very difficult to obtain a consistent concentration of CBD
- The heat can potentially damage the extract and affect the cannabinoids in the CBD oil
- A very high quantity of hemp is required
At ReThink, we use a CO2 extraction for our Broad-Spectrum CBD products because it is generally advised as the most efficient method across the industry. It may be the most expensive & complex method available, but it enables us to create the best possible oil.
It allows for adjustable CBD concentration, high yielding extracts for potency, no toxic residue and no chlorophyll, for safer, better tasting, more effective CBD products.