New techniques for the extraction & preparation of cannabis oil: an interview with Alison Wake
Alison Wake is the Product and Marketing Manager, Genevac
Can you please give an overview of the recent changes to the legalized use of cannabis for medical and recreational purposes?
Cannabis first began to be decriminalized and legalized for medicinal use in the US in the late 1990s and 2000. However, the production of cannabis and cannabis extraction as an industry remained limited until recently when recreational use began to be legalized. That began in Washington and Colorado in 2012.
Since then, cannabis has now been legalized for recreational use in five US states, as well as for medicinal use in Canada and a total of 27 US states. Several additional US states will be focusing on legalizing cannabis for medicinal and/or recreational use this coming November, so it’s an ongoing process.
In states where cannabis use has been legalized, whether it is for recreational or medicinal use, the market is then highly regulated, with separate licenses for growers and extractors, which are sometimes known as producers and manufacturers, and distributors or retail outlets.
Outside North America, the cultivation, sale and possession of cannabis remains illegal in most countries. However, in some countries, such as the Netherlands, Spain, Switzerland, and Portugal, for example, personal use has been decriminalized. Some countries have also legalized it in order to allow medical use and on the back of that, have been allowed limited production for this market. Examples include Finland, France, Germany, and Israel.
What impact have these changes had on the demand for the extraction and preparation of cannabis oil?
Cannabis is one of the fastest growing markets in the US and is estimated to be worth in excess of 7 billion dollars in 2016. Products are sold in many formats such as dried plants, dried flowers and leaves, and increasingly in purified forms such as oils and waxes. These extracted forms are used in e-cigarettes for vaping and can also be incorporated into drinks, edibles and so on.
The production market is being driven by demands for specific and pure cannabinoid extracts. Tetrahydrocannabinol (THC) is the most common and well-known active ingredient in cannabis. It produces the high that the recreational users are looking for. In addition, THC and other cannabinoids are said to offer therapeutic benefits, such as anti-inflammatory, antispasmodic, anticancer, anti-convulsive and anti-insomnia effects. Many more additional benefits have been reported, depending on the mixture and concentration of various active ingredients.
Terpenes are the pungent oils that give cannabis its distinctive flavors and fragrances. Variations of terpene contents are obviously important for the recreational cannabis, but it is also thought to act synergistically with THC and other cannabinoids, for medical applications.
Therefore, although the cannabis market still holds something of a stigma, with legalization, it is rapidly becoming a legitimate market in the US and Canada and, particularly, the increased activity in medical marijuana research lends legitimacy to this market.
Although the recruitment of trained lab staff by producers can be hindered by the persistent stigma, cannabis companies are also beginning to recruit scientists from the pharma and biotech fields.
How do new extraction and preparation techniques compare to previous methods?
The oils are extracted from cannabis plant material and the raw extract is distilled to remove unwanted material. Extractors typically utilize one of three extraction methods.
Butane extraction is a really old method that dates back to the 1960s and it’s falling out of use, partly because of the high explosion risk. With back-yard cannabis producers, there are quite a few explosions.
Solvent extraction is probably the most common method at the moment. A range of solvents may be used, but primarily, ethanol extraction tends to be the choice.
Finally, supercritical fluids chromatography (SFC) or CO2 extraction is an expensive, but increasingly common method, particularly when extractors are looking for specific components.
The raw extracts contain a variety of fats and waxes, as well as the target cannabinoids and to remove these inert materials and concentrate the active ingredient, they have to go through a refinement process called winterization: the raw extract is cooled, which solidifies the contaminants so they can then be filtered out.
Whichever extraction method is used; some form of distillation or removal is required to remove the solvents. The method of first choice is usually a rotary evaporator, but increasingly, extractors are looking to increase the throughput by utilizing the Genevac Rocket Synergy centrifugal evaporation system.
Can you please give an overview of the Rocket 4D Synergy?
Genevac developed rocket technology to enable very fast evaporation of large volumes of solvents. The system uses a patented process, utilizing temperature controlled steam to safely drive a fast evaporation, without damaging the product.
Fitted with a removable stainless steel evaporation vessel, or bowl rotor as we call it, the rocket synergy can evaporate batch volumes of up to five liters and the rocket 4D synergy features an automatic system, which allows many tens of liters to be processed, without any user intervention.
The rocket monitors and controls all these parameters during the evaporation and then stops automatically when the products are dry or concentrated. Once loaded and started, the system will operate completely unattended.
Also, Rocket Synergy evaporators include patented Genevac DriPure technology, which prevents bumping and foaming – a major issue in natural product extraction. Foaming of the product can inhibit the evaporation and cause back flow and so on.
Has the Rocket been tested against the industry standard rotary evaporator? How does the Rocket compare?
The rocket was evaluated by one of our customers, California Gold Extraction in California, in a direct comparison with the rotary evaporator. Overall, the Rocket was found to provide a superior drying solution, offering automated evaporation, as well as a greater, more flexible throughput than the rotary evaporator.
Evaporation time was reduced, while maintaining an acceptable residue solvent content at the end of it. The system required no user input following start-up, whereas the rotary evaporator needed frequent attention during the run to maintain an appropriate evaporation rate. By contrast, the Rocket automatically controlled the vacuum and supplied heat energy.
It monitored the evaporation rate throughout the run, collecting and draining the solvent from the integral condenser and stopping automatically when the solvent had been removed. Since no user intervention was required, the operator was able to complete other tasks during the evaporation run.
In addition, the system monitored parameters automatically during the run, which meant that there was a more consistent operation and subsequent product quality. There is a paper and a video about that evaluation available on our website.
How can the Rocket 4D Synergy be used in the process of production scale up?
Solvent evaporation during the extraction process, or after winterization, is a key process in the refinement of cannabis extract. Rocket Synergy evaporators with their auto stop and DriPure to prevent foaming, offer a fast and unattended batch production.
Key to production scale-up is the very large volumes of up to many tens of liters that can be processed without operator intervention, using the automatic feed system on a Rocket 4D synergy.
How does the Rocket 4D Synergy differ from previous models?
The Rocket was originally designed for six flasks of 400 ml of solvent. It was OK for fairly large volumes, but not for bulk process scale. The Rocket 4D had a fixed bowl rotor for batch and feed processing. However, on the Synergy Series, we’ve now got interchangeable rotors on both systems.
So you can have one system, Rocket Synergy, that’s able to do a 5 liter batch and your flasks, or with the Rocket 4D Synergy you’ve got your 5 liter batch and feed capability, and your flasks.
You’ve got a system that can be used both for research, where you’re working with smallish volumes to build up your process. You can then move up to a batch, 5 liter process. Then, if you’ve got a 4D system, you can then move up to a feed system for your actual production. One system will give you the ability to do your evaporation, right from your research, up to your production.
What do you think the future holds for the techniques used for the extraction and preparation of cannabis oil?
Cannabis extraction has historically been a bit of a back-yard, garage industry, partly because it was illegal and there were a lot of amateur chemists using outdated methods to produce unrefined products. With the results of research increasingly indicating that individual components of the cannabis have distinct actions, a more focused approach to the extraction and refinement process is required.
Extraction methods are commonly being optimized to tailor yields of particular components, with increasing application of methodologies such as the SFC that I mentioned, meaning producers are able to offer a greater selection of purified products.
How do Genevac plan to meet increasing demands for efficient drying solutions?
As has been demonstrated with the Rocket and Rocket 4D synergy, they offer superior drying solutions compared to the traditional methods such as rotary evaporation. The ease of use and increased efficiency freeing up operators to do other tasks, means increased production demands can be more easily met.
Since Genevac evaporation systems have bespoke methods built in and control evaporation parameters very precisely during the run, they have more consistent operation and yield a reproducible product. Evaporation methods can also be tailored to maximize efficiency, as well as being optimized for solvent recovery, thereby providing an ideal solution for production and refinement of individual cannabinoids.
Genevac has a team of application chemists who can tailor methods specifically for each customer and methods have been optimized to reduce the residual solvent. We developed a customized method for one client, which is used to recover terpenes from waste processed solvent. This method cleans the solvents, for re-use, at the same time as recovering the valuable terpene extract, which can then be re-added into their product.
Even outside of the US and Canada, this methodology is applicable to other natural product applications such as herbal remedies and so on, where they’re doing oil extractions.