Advances in Whole Plant Cannabis Extraction

Cannabis extracts are quickly becoming more popular across the legal cannabis market. As the product offering expands and the use of these products becomes more mainstream, focus is slowly shifting away from whether consumers might use these products, and towards the question of exactly which ones a consumer should choose.

While some manufacturers are creating products with the purest CBD extract, or the most potent THC extract, others are taking a more holistic approach to extract making.

What are whole plant extracts?

Cannabinoid extracts are normally made using the flower, which is the part of the plant that contains the trichome resin glands that produce the sought-after cannabinoids. By sticking to the flower and the bud, processors are more easily able to isolate and purify individual cannabinoids of interest, and package them ready for use.

In contrast, whole plant cannabis extracts are made from the flower and the leaves of the cannabis plant. Whole plant cannabis extraction is normally done in order to produce a full-spectrum cannabis extract – one that contains more minor cannabinoids, such as cannabinol (CBN) and cannabigerol (CBG).

Depending on the extraction method used, whole plant extraction is sometimes able to preserve the terpenes and flavonoids produced by the cannabis plant, which can give the extract more of a cannabis-like flavor. This can be appealing to recreational consumers who want to feel more closely connected to the cannabis culture despite not wishing to actually smoke the drug.

But more importantly than enhancing the flavor, producers of full-spectrum cannabis extracts will talk of the “entourage effect” caused by the presence of pharmacologically active minor cannabinoids and terpenes with CBD and/or THC. The entourage effect is the name given to the synergy observed in multiple studies where a combination of CBD and THC, or a combination of major and minor cannabinoids or terpenes, is able to cause a medicinal effect that is far greater than the sum of its parts. For example, some studies show that past a certain dosage the effectiveness of pure CBD as a medical treatment reaches a state of diminishing returns; in contrast, when using CBD combined with other cannabinoids and terpenes, this reduction isn’t seen to the same extent. At least in theory, then, this makes full-spectrum or whole plant cannabis extracts interesting from a medicinal use perspective.

How are whole plant extracts made?

Preserving as many of the terpenes, flavonoids, and minor cannabinoids as possible during cannabis extraction, as is often desired by those doing whole plant extraction, is a tricky business.

Terpenes are highly volatile molecules and will degrade readily when exposed to more than mild heat. As a result, extraction methods such as alcohol extraction are almost totally unsuitable, as the heat needed to boil the solvent during the extraction process will damage the terpenes.

Supercritical CO₂ extraction is a popular choice for whole plant extraction, as it’s capable of producing a high-quality full spectrum extract using a low heat and no dangerous solvents.

In a typical supercritical CO₂ extraction, CO₂ gas is turned into a supercritical fluid using a high pressure system. This supercritical CO₂ can then be passed over the cannabis plant material, which acts like a solvent to draw out the oils and waxes from the plant. The resulting extract retains much of the cannabis plant’s original chemical profile, including the more minor terpenes and cannabinoids.

Trends in whole plant extraction

Now the companies that produce these whole plant and full-spectrum extracts are having to find ways to differentiate themselves from their competitors by creating their own unique approaches to extraction.

For companies like Heylo, a Seattle-based cannabis extract producer, this has meant moving away from cannabis extracts that are optimized for super-high THC levels, and towards a more natural extract that aims to be as close to the plant as possible.

“Every extraction method has unique advantages and drawbacks,” explained Lo Friesen, the founder and CEO of Heylo, to Analytical Cannabis in June.

“Our proprietary method, which we call RawX, aims to retain as much of the plant's original chemical profile as possible. This stems from a philosophy that the best cannabis extracts are the ones that are the ‘closest’ to the actual flower. The method has two fundamental steps: source high quality material, and respect it at every stage of extraction.”

Key to the RawX proprietary method is a supercritical CO₂ extraction, done under relatively low pressures and temperatures, over a long period of time. It aimed to minimize the amount of post-processing that needs to be done to the product following the CO₂ extraction.

As well as being useful for the creation of full-spectrum extracts, whole plant extraction is also being used to manufacture the latest trend in cannabis extracts, "broad-spectrum extracts."

These extracts are similar to full-spectrum extracts, but with one key difference: no THC. These extracts aim to offer themselves as an alternative to pure CBD isolate, which can still boast all the medicinal effects of CBD taken in combination with the more minor cannabinoids, but with none of the intoxicating effects of THC.

Big Sky Botanicals is one of the many brands now manufacturing broad-spectrum CBD extract. Their process begins with either supercritical CO₂ or ethanol extraction being used to produce a full-spectrum cannabis extract from whole plant hemp. This extract can then be processed further using a unique chromatography process to filter all detectable THC out of the extract.