Which cannabis extraction method should I use?

With so many different extraction techniques available and seemingly all of them boasting to be "the best," it can be difficult to decide which type of extraction to add to your next cannabis SOPs (cannabis standard operating procedures). Regardless of which method you choose, large scale extraction setups are a costly investment. No one wants to invest heavily in something without having a great deal of confidence that the investment will pay off in the long run.

So which extraction method should you choose? First you must decide what your goals for extraction are. Each different extraction method results in a slightly different product. There are also differences between methods including time spent on extraction, and purity of extraction. Because of this, it is important to keep in mind what your goals are and to select an extraction method serving those goals.

Some extraction methods are utilized for the quality and desirability of the final product. Extraction methods such as bubble bags and rosin presses will deliver artisanal results. The products of these extracts are extremely flavourful and many cannabis purists will choose these types of extracts over those made with organic extraction solvents.

Rosin press hash is as much like an art form as it is an extraction process. Rosin presses use heat and pressure to liquify the cannabinoids and to press them out of the plant material. The heat and pressures used can vary and this is where the art aspect comes in.

Rosin is typically a low yield extraction method that produces extracts which maintains many of the flavour qualities that the cannabis flower has. The high quality of the extracts along with the absence of solvents in the extraction method make this an appealing product to many cannabis consumers.

The low yield and lower cannabinoid potency extracts resulting from this method makes it difficult for a team without an extractionist with a significant amount of experience in this method.

Much of what was said about rosin press hash products also applies to water hash products. The method produces a lower cannabinoid potency extract that appeals to cannabis users looking to avoid extracts made with organic solvents.

Bubble hash differs from rosin hash greatly in the way in which it is made. Compared to many other forms of hash, bubble hash is quite labour intensive. Technology for large scale bubble hash making is not on par with other large scale extraction methods.

Due to production constraints associated with bubble hash and rosin press extracts, these methods are typically not done on the same scale as hydrocarbon extraction, CO2 extraction, or ethanol extraction.

The resulting flavourful extracts as well as the fact that potentially harmful solvents never touch these products, mean there will always be a market for these types of extracts. That market will however likely always remain relatively small, much like the extraction capacity of these methods. These methods are for those who want to make high quality niche products and do not mind the time and effort required to master these methods.

When it comes to large scale cannabis extract production there are three main types: hydrocarbon, CO2, and ethanol extractions. One could argue that when talking about really large-scale extraction throughput, it comes down to either ethanol or supercritical CO2.

For the sake of this article we will consider anything over 20 pound batches to be large-scale even though many hemp extraction labs process quantities large enough that 20 pounds is considered extremely small.

CO2 extraction is widely employed in both recreational cannabis and hemp industries. The reason for the broad applications of CO2 extraction is due to the tunability of CO2 as an extraction solvent.

By adjusting the temperature and pressure of the CO2 extraction, it is possible to modify which compounds will be extracted. This allows extractors to run multiple passes on the same material to extract different compounds with each pass. This enables extractors to choose between runs offering higher purity extracts by sacrificing yields or runs with higher yields with a sacrifice in purity.

It doesn’t have to be a choice however, as extractors can run a high purity run at subcritical conditions and then run a high yield run at supercritical conditions. This tunability emphasizes the power of CO2 as an extraction solvent.

When CO2 is run in subcritical conditions, the solubility of many of the plant compounds is reduced; including unwanted compounds such as chlorophyll. Alternatively when CO2 is run under supercritical conditions, the solubility of many of the compounds, including chlorophyll, is increased, meaning more compounds are removed from the plant material.

It is not uncommon for extraction companies to vary the temperature and pressure of CO2 extractions for different products. Often companies aiming to produce high quality vape pens will run an initial pass on the material to first extract just the plant terpenes.

They will then run a second pass increasing the temperature and or pressure of the extract to remove the cannabinoids in a subcritical extraction. The two passes can then be mixed back together for use for vape pens.

The same extractor might then run a supercritical pass on the material to remove any remaining cannabinoids and other plant compounds, such as flavonoids that have therapeutic properties, for use in topical compounds.