CBD (Cannabidiol) oil is the ubiquitous product associated with CBD and derived from hemp.
Interest in the cannabis plant and the potential benefits of CBD oil is at an all-time high. With medical marijuana legalisation in the UK in late 2018 sparking internet searches about both cannabis and if CBD can you get you high (spoiler: it can’t!) or if CBD oil is legal, we have triggered a new wave of CBD wellness.
But how is CBD oil made and what should new users of CBD know about different cannabis extraction methods?
It’s important to note that not all CBD oil is made equal, and there are varying grades of CBD products on the market, unfortunately creating confusion coupled with a lack of customer trust.
Before we dive into cannabis extraction methods, it’s useful to know that CBD oil production often starts with a clone cut of a previous hemp plant either sourced from a prior harvest or another grower. This gives farmers visibility of potential yield and average CBD/THC content before planting the cutting as they have at least one former plant to base this on.
What does all that mean?… Keep reading!
Using a clone (cutting) of a previously grown hemp plant farmers can ensure the crop meets their exact requirements in terms of CBD/THC or other cannabinoids percentage. Using seeds is another possibility, but this route adds ambiguity around the cannabinoid makeup of the plant along with the exact weighted yield when harvested.
A clone is a cut of a previous plant derived from the stem of a small but new leaf is used instead of a seed. This is then 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.
Although hydroponics is associated mainly with growing medical marijuana or hemp flowers, where the size and look of the flowers is near as necessary as content.
This clone then grows into a fully grown hemp plant, and the farmer can base its projected yield on previous plants, meaning they can ensure the plant will be suitable for extracting CBD oil from.
While this is just step one of how CBD oil is made, it’s critical to ensure the right chemical compounds are found in the extract when harvested.
10-16 weeks after planting the plants mature and they are harvested to move onto the next stage of the process: drying and curing.
Once harvested, the hemp plants are hung upside down to dry and cure. This is usually somewhere with optimum humidity (58%-62%) to avoid mould and mildew.
Usually, the curing process lasts around 30 days. After which the aerial plant parts of the cannabis plant (trim and low lower quality hemp buds) are processed by separating them from the seeds and stalks of the plant.
Premium and cured hemp buds are often sidelined to be sold separately as hemp flowers due to optimising product margins.
However, this can vary depending on the legislation in the country of extraction.
For example, in Colombia, all parts of the hemp plant have to go to extraction due to strict regulatory rules.
Resulting in growers batching different qualities to be sold as crude CBD oil at varying prices e.g batches of oil produced from flower, trim or everything else.
In the CBD industry, the aerial plant parts are known as hemp biomass, which is ground down by a machine into a coffee ground like substance for processing into an extract. These grounds contain a full spectrum of cannabinoids including CBD and THC.
The CBD, along with other cannabinoids and other beneficial compounds in these hemp grounds is then extracted. This is either by using a solvent such as ethanol directly added on top of the biomass and left to work or by pumping the mixture through a highly pressurised machine which uses CO2 (acting as a solvent) at a very high pressure.
Once passed through the solvent, the end product is CBD crude oil which is then filtered and further processed at a lab to post-process and formulate products including CBD concentrates and oils.
Most people are not aware, but post-processing can include the creation of a variety of CBD oils. For example, there are multiple processing steps to create CBD isolate and another couple to produce broad-spectrum (0% THC) CBD oils.
Let’s run through each cannabis extraction method in more detail to familiarise yourself with the advantages and disadvantages of each:
The gold standard to extract CBD oil uses highly pressurised carbon dioxide known as a supercritical state, to separate the compounds in the plant material.
This is the most common extraction method you will see used for CBD products, and there is a good reason for it: supercritical CO2 is highly efficient. It uses no solvents per se (CO2 acts as a solvent at high pressure) so there is no risk of residual solvents left behind in the final product.
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 the ground-up biomass. The CO2 targets cannabis trichomes, containing 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 incredibly expensive machinery which can operate at high pressure (1500 – 5000 PSI), making economies of scale difficult due to the engineering prowess required and sheer space.
Supercritical CO2 tanks feature thick casings to encapsulate the pressure for safety reasons. As a result, the machinery is heavy, bulky and large.
Nonetheless, the CO2 process has more advantages than disadvantages for most growers, making it by far the most popular method to produce CBD oil.
All Nature & Bloom products are derived using supercritical CO2 extraction, given the superior extracts made possible through CO2.
Ethanol is a widely available and highly effective solvent and producing CBD oil. Cryo-ethanol, also known as cold wash ethanol, is where the solvent is used at a cold temperature for extraction.
While explicitly adding solvents on top of biomass has had its share of bad press, it’s still a beneficial and cost-effective (especially at scale), way to isolate cannabis compounds and maintain other plant matter intact.
For this reason, some of the most extensive 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.
Hydrocarbons by nature are potent solvents when used for the manufacture of CBD oil.
A quick blast of butane over hemp biomass can extract CBD from hemp very quickly and with acceptable efficiency for smaller producers.
Hydrocarbon solvents such butane and propane were popularised initially for use in recreational marijuana markets to create concentrates, but artisan CBD oil manufacturers also employ them.
Butane and propane hemp extracts usually have a vibrant golden colour and are rich in terpenes.
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 cannabis.
However, at scale, hydrocarbon extraction such as butane presents engineering and economic challenges. As a result, butane is often sidelined in favour of ethanol by some of the larger CBD cannabis oil producers.
While the previous methods to extract cannabinoids are the most popular and the practices employed by industrial producers of CBD oil, there are a couple of other super exciting craft methodologies.
These methods are often employed in the United States to create solventless extracts, with a particular focus on THC, but we expect these to push into CBD production anytime now!
The issue with these methods is while there is a place for them, they are not as efficient as the previous methods to create products which exceed 90%+ purity.
These craft producers will likely flourish in premium market segments, especially those outside of just CBD oil. Still, compared as a process those as those mentioned above these craft methods do not directly offer the opportunity to remove cannabinoids like THC selectively. As a result, it’s unlikely we will see these methods employed commercially by the larger extractors.
Hopefully, this post has ironed out any questions you have around how CBD oil is made, including the various methods available and impact on product quality.
While most people (including us) prefer CO2 extracted CBD oil, there is a place for all the methods mentioned here. Especially as the market continues to grow, and new producers looking to enter the market, CO2 being cost-prohibitive usually requires raising significant capital just to get started!
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.