CBD (Cannabidiol) oil is the ubiquitous product associated with CBD and hemp. Not all CBD oil is made equal and the varying grades of product on the market have created confusion coupled with a lack of customer trust. Adding to the noise, CBD oil can be extracted from both hemp and marijuana, both of which fall under the genus cannabis. Confused yet?
Hemp originates from the cannabis sativa variety of the cannabis genus and it will not get you high. Why? Because cannabis is classified as hemp if it contains <0.2% THC (EU)/ <0.3% THC (USA)/ <1% THC (Switzerland). Where THC (Tetrahydrocannabinol), is the psychoactive component in cannabis which makes users feel ‘high’. Marijuana on the other hand, usually features double digit THC percentages and close to zero CBD.
CBD is primarily extracted from hemp, due to the illegality of marijuana and the economic implications of meeting THC threshold requirements. Using hemp allows manufacturers to reach a wider market and permits for economic efficiencies as CBD is the core product harvested from the plants, usually using the whole plant and requires no removal of THC (as the plants are already producing on average below the THC threshold limits).
Using a clone (cutting) of a previously grown hemp plant farmers can ensure the crop meets their exact requirements in terms of CBD/THC percentage. Using seeds is another possibility, but this route adds ambiguity around the cannabinoid make up of the plant when harvested.
A clone is planted like a seed in the soil or using a mineral rich hydroponic system in the absence of soil. Where, hydroponic setups are used primarily indoor and permit for pre-set watering conditions to mimic the best case scenario. These are largely associated with growing hemp flowers, where the size and look of the flowers is near as important as content.
After 10-16 weeks the plants mature and they are harvested to move onto the next stage, drying and curing.
Once harvested, the plants are hung upside down to dry and cure. This is usually somewhere with optimum humidity (58%-62%) in order to avoid mould and mildew.
Usually, the curing process lasts around 30 days. After which the flower is processed by separating it from the seeds and stalks of the plant. This is then ground down by a machine into a coffee ground like substance.
The CBD in these grounds is then extracted from the hemp grounds, usually via using ethanol or CO2 at a very high pressure.
Let’s run through a couple of the most common ways to extract CBD from hemp.
The gold standard extraction method uses carbon dioxide at very high pressure, known as a supercritical state, to separate the compounds in the plant material.
Usually, CO2 is a gas, but to use it for extraction purposes, it needs to turn into a liquid where it acts as a solvent. To achieve this, CO2 is compressed and heated at the same time, morphing into a high-pressure gas and fluid at the same time.
This substance is then blasted at ground-up hemp flowers. Targeting the trichomes, which contain all the cannabis compounds desired for extraction, including cannabinoids, terpenes and flavonoids. This process is known as a supercritical fluid extraction.
While this is considered the benchmark, it requires expensive machinery which can operate at extremely high pressure (1500 – 5000 PSI), making economies of scale difficult due to the engineering prowess required and sheer space.
Advantages/Disadvantages of CO2 extraction include:
While using solvents has had some bad press, it’s still a beneficial and cost-effective (especially at scale), way to isolate cannabis compounds and maintain other plant matter intact.
Butane and propane are the most popular solvents used in small to medium-size facilities, and the machinery usually operates at between 50-100 PSI.
These two catalysts are non-polar solvents, with a low boiling point, meaning they bind perfectly with the plant matter while preserving all the desirable compounds found in hemp.
Popular with moderate size farms, producing artisanal CBD products, butane and propane hemp extracts usually have a vibrant golden colour and are rich in terpenes.
However, at scale, hydrocarbon extraction such as butane presents engineering and economic challenges. As a result, some of the largest extraction facilities often use ethanol. Improving end unit economics, as there is no need to maintain pressure, and it has less flammability than butane and propane.
Advantages/Disadvantages of solvent extraction
Disclaimer: Views expressed here do not necessarily reflect those of Nature & Bloom and its staff. This article is not intended to provide medical advice, diagnosis, treatment, cure or prevention for any disease. Nature & Bloom products have not been evaluated by the MHRA.