The first installment of this column examines the development of various extraction technologies.
This first “Tech Innovations” column examines the development of various extraction technologies. Extracting from botanicals is an age-old process that dates back hundreds of years, including in processing for cannabis. But now there is more interest in what extractions can do, how they can be accomplished, and what new processes or equipment can be brought to bear. This column focuses on defining extractions, looks at new technologies, including goals and objectives, what can be done with artificial intelligence, and more. We also take a look at other extraction products, techniques, and developments as discussed with various extraction experts who are working both in laboratories and with extraction equipment manufacturers throughout the country.
Extraction technology is one of the quickest evolving manufacturing processes of the cannabis industry, which is ironically one of the oldest processes for cannabis.
Hundreds of years ago in places like Morocco, the black finger hash concentrate was simply the resin from the trichomes of cannabis plants collected during hand-processing cannabis plants. The processor would roll the sticky substance between their fingers and present it as a product for sale.
What has reinvigorated extraction technology in the early part of this century was the demand from consumers to make a product with a stronger tetrahydrocannabinol (THC) percentage content.
The demand for newer, stronger cannabis products began around 2012, when recreational cannabis was legalized in Washington, and recreational consumers began looking for the strongest high they could find. That trend continues, but a growing number of consumers are interested in the cannabinoid profiles of the product, looking for a certain balanced ratio of cannabidiol (CBD) to THC in their product.
Most flower being sold when cannabis was legalized for recreational consumption was in the range of 15% to 23% THC, while the earliest cannabis extracts that were coming mostly from black market laboratories at that time were typically in the 60–80% THC range.
Better extraction technology has moved into the limelight now, out of the makeshift basement and kitchen laboratories and into legitimate ones, addressing a different consumer demand-more specific cannabinoids and terpenes, produced exactly the same every time, using developing methods sometimes coming from chemists and engineers bringing their work to the cannabis industry from other botanical extraction companies.
In Tables I–IV presented here (see right, click to enlarge), we showcase some of the new extraction products that have been brought to market since 2019. Cannabis Science and Technology sent out a survey in early 2020 asking vendors to supply them with any extraction products launched within the last year. This article presents those products broadly in Tables I–IV. Because information for this article is obtained sporadically over the course of many months, it is very possible that some information has been missed. The reader is encouraged to check with specific vendors for additional products as well as more-detailed information regarding what is covered here.
Today, concentrates made by oils gathered from new extraction technology-such as shatter, hash, live resin, butane hash oil, budders, diamonds, among others-mark a growing percentage of products being offered, along with surging sales. Industry research (1) in 2019 predicted that sales of concentrates would be about $14 billion by 2026.
Newer extractions products, like diamonds and sugars, are basically recrystallizations given catchy names because of what they resembled. They are new to the cannabis industry, but not in the world of organic chemistry.
“That recrystallization process is something you learn in the first semester of organic chemistry lab,” said Amber Wise, medical director at Medicine Creek Analytics. Medicine Creek Analytics is a cannabis analysis laboratory near Seattle, Washington. “Those are most easily achieved with hydrocarbon extractions, but can also be done with CO2, just less efficiently. The diamonds and sugars are made with solutions that are super-saturated with cannabinoids, meaning that they are no longer stable solutions for the long term. If you let it sit long enough or cool it down slowly, pure crystals will form over time.”
Extractions have typically been done using three methods:
CO2 processing equipment is generally the most expensive (2), with some starting at around $90,000, and able to process 10–14 lbs in 24 h.
What is new in the cannabis industry is how chemical engineers who are experienced in older extraction processes with botanicals such as olive oils and vanilla oil are applying their experience to the cannabis industry, according to John MacKay, an internationally recognized cannabis analysis expert with Synergistic Technologies Associates. “It’s a bridge between botanicals and cannabis,” said MacKay.
MacKay offered a clarification about extractions. “When you make kief, that is not extraction, it is separation,” said MacKay. “When you are grinding or doing pressing, that is not an extraction, that is a separation. When you have something that is a liquid and you put it up against a solid, and concentrating by that, that is an extraction. When you are playing with extraction, you are playing with solubility.”
MacKay said that the best method of extraction is to “start with the end in the beginning” (3). An operator doesn’t decide on CO2, butane, or ethanol as the process-he or she starts out with what they are trying to make. “People are actually going backwards, and that is the way you do science,” said MacKay. “Making a vape pen, a gummy, a chocolate, a distillate-it doesn’t matter what it is. You start off with what you are trying to make, and you back up to how you get those ingredients, and you back up from there to figure out what type of extraction process will provide you with those ingredients for the products you are making. And from there, you back up all of the way to the chemovars so that you know which plant will provide you with that opportunity, or how you manipulate the plant to be able to get the ingredients you want.”
Wise said the extraction you want depends on not only what kind of end products you are making, but also what sort of molecular profile you want out of that product. “If you really want to save terpenes, ethanol is not a great method,” she said. “It’s really great for extracting all of the cannabinoids, and it’s high throughput, but it’s pretty difficult to isolate the terpenes from there.”
She designed the terpene isolation process at another company, which used one of the fractions out of the CO2 extractor and distilled that fraction separately to isolate the terpenes. They would clean up the cannabinoid fractions first, then combine the terpenes with everything at the very end.
“It’s really hard to give all-encompassing statements about the extraction process, for instance naming the best extraction solvent. There are so many variables that go into different processes,” said Wise.
CO2 is the most tunable, she said, in terms of being able to change the pressure temperature profile, which is what dictates the profile you get out of the collection chamber. “But if you are a giant facility and just want to extract a ton of CBD from industrial hemp, for example, you should go the route of ethanol.”
Wise said that groups of molecules can’t be highly purified using CO2 alone, but the operator can get enriched fractions. “What that means is you can’t separate out similar molecules like THC and CBD, but you can get THCA rich fractions with small amounts of THC in them, for example,” said Wise.
The focus recently for extractors has been on terpenes. “There are so many different kinds of extraction processes, and what you collect out the other end might have terpenes in there or might not, depending on what extraction process you are using,” said Wise. “You can isolate the terpenes before you even extract the cannabinoids.”
Why are extractors focusing more on terpenes-the flavor and aroma of the cannabis product? “We are focusing on it more because consumers want more interesting terpene profiles because it really does give you the different effect of the different strains,” said Wise. “If you are making concentrates and you want to claim it’s Blue Dream, you need to have some Blue Dream terpenes in there or otherwise it’s just a bunch of THC in there and that could come from any strain.”
The focus is actually more about the entourage effect (4) explained Wise. “I think it’s that people are figuring out that the entourage effect is actually a scientific thing and not just a bunch of a stoners pretending it is a placebo effect,” she said. “If you just isolate THC you don’t get very high, it doesn’t last long and it’s not interesting. So we need to be making formulations of concentrates that are beyond just cannabinoids. There are a number of other molecules that are also important in the entourage effect.”
There are other, perhaps more exotic methods being investigated now, such as ultrasound assisted extraction (5), a more efficient extraction tool that enhances yield; and a hybrid approach of using ultrasound assisted extraction with microwave-assisted extraction (6) for fast, efficient extractions that can bring additive or synergistic effects.
Another newer extraction technology is hydrodynamic extraction, as demonstrated by iaso (7) in 2018, which is a process that converts the cannabis plant material into a cannabis nano-emulsion using hydrodynamic force and ultra-sonification to break the cell walls of the plant material and release them into the aqueous phase.
This also enhances the bio-availability of the extract. The next step is a cold extraction process using temperature generated during the hydrodynamic process for pulling out the active total cannabinoids from the clear emulsion into the solvent phase.
“The key is hybrids,” said MacKay. “Whether you have it go through a process where you break up the trichome material with microwave, such as in microwave-assisted extraction, or you break it open with ultrasound. You can do it through pulsed electric fields (8). People are starting to understand that if they merge these together, a separation and an extraction, then they can utilize what is already out there.”
Newer ideas being explored involve artificial intelligence (AI), which helps bring more data analytics into the extraction process.
Andy Joseph, president at Apeks Supercritical, makers of CO2 plant oil extractions systems, is an industrial engineer with five extraction-related patents. Apeks Supercritical was founded in 2001, and started building extraction equipment back in the early 2000s, focusing on botanical oils and flavors. “That got attention from the cannabis industry in 2009,” said Joseph.
“Automation to me is an expected, it’s not an option,” he said. “The cannabis industry early on was the exact opposite. It was a black market environment. The idea of automating something to them was just another way for the cops to get involved.”
Extraction processing without automation presented problems, such as lack of consistency, and differences in outcomes from operator to operator. But automation has its drawbacks as well. “Automation can only take you so far,” Joseph says. “It can automate the ‘process.’ But it doesn’t let the operator see inside the equipment.”
He explained how AI could work in the extraction process: “The CO2 equipment operates at high pressures, 1000 to 5000 psi in a batch-type configuration. We are talking botanical oils,” said Joseph. “So we got a Mother Nature element going. And Mother Nature is never the same.”
Operators program their automated control system to run an extraction at a certain parameter set. “But the best operator with the most consistent material he can find still doesn’t know when the extraction is maximized, when to shift the parameters of the extraction to get the target cannabinoids or molecules that he or she is looking for,” said Joseph. “That is where AI starts to come in.”
With AI, the operator would have the ability to look inside the extraction in real time, with sensors that can detect the differences between molecular weights as the extraction is going on. “Now the operator can say ‘Hey I am ready to switch from the terpenes, the volatile compounds, to cannabinoids.’ The machine says ‘Hey it’s time for me to switch.’ And then it does so automatically. That is the next level of automation, or what we call AI.”
Joseph said that the AI extraction process that they are developing is based on “refraction” technology, which is a trademarked process that denotes a combination of the words “reflection” and “fraction.”
In the process, the operator shoots infrared light into and through the stream of CO2 and the oils mixed in it. The operator then reads the reflection of that light, and crunches the numbers to find out what they are seeing. Fractioning refers to the separation of different molecular weights, such as fractioning off the terpenes.
“We can use refraction technology to drive the decision as to when we stop fractioning terpenes, for example, and start fractioning different cannabinoids and different molecular weights,” said Joseph.
One advantage of this process is for the artisanal cannabis manufacturer. Grabbing and controlling specific molecule weights can make the artisanal cannabis manufacturer more efficient. “This technology gives vision into the equipment while it is operating so the operator can make smart and efficient decisions to create that artisanal product that they want to do,” said Joseph.
Getting the AI process to work will take more time. One issue is understanding the THC molecule in the CO2 process. “As the density of the CO2 changes with changes in pressure, so does the environment around that THC molecule,” said Joseph. “It’s not that it is modifying or changing the molecule itself, but everything around it is changing. It looks different because it reflects light differently. So understanding what it looks like at different temperatures and pressures is part of the calibration process we have to go through in order to implement this technology.”
He said that they are in the beta phase of working out details of the process, and have done trials on materials at different locations to prove that the technology works. Now they have to get the beta piece of equipment into an operator’s hands, which they expect to do sometime later this year. “The problem with beta is that it takes a boatload of work to be able to crunch the numbers we get during the process,” he said. “We are in this calibration phase where we have proven it works, but proven it works over time in different environmental characteristics, like changes in plant material from California to Maine for instance, are calibration sets that we are looking for. We need to prove the technology in different environments to be able to prove that it works consistently no matter where we put it.”
Is machine learning part of this new AI processing?
“We don’t have the technology yet,” said Joseph. “Where the machine says ‘Hey I did this and here are the results and now I am going to change what I do.’ That is a fairly complex process. We are still in the infancy of applying that. But absolutely, that is the direction we are going with this technology.”
MacKay said that if you do principal component analysis, and you do chemometrics, which is a simple part of AI, then yes, the machine can learn. “Machine learning can work as long as it always sees the same product. You have to make sure what your moisture is. You have to have that information that AI can use as a functional variable and then see what happens as it’s impacted.”
He said that the people who are going to “knock it out of the park” in extraction technology are the people who have spent the time looking at the entire process.
“There are places where they do not touch the cannabis from the time it comes in from the truck, to the time it’s an oil ready to be placed in a product,” said MacKay. “It never gets touched. It goes from one mode to another. It comes in and comes out the other side. It’s like Willy Wonka.”
Product reviews such as the present work would not be possible without the contributions and cooperation of the manufacturers that responded to the Cannabis Science and Technology survey. Their effort is greatly appreciated. Although Cannabis Science and Technology has made every attempt to include every submission, it is possible that some have been missed. If there have been omissions or if you want to be sure to be included in the 2021 new extraction coverage, please contact Megan L’Heureux, Editor-in-Chief, Cannabis Science and Technology, at firstname.lastname@example.org.
David Hodes has written for many cannabis publications, and organized or moderated sessions at national and international cannabis trade shows. He was voted the 2018 Journalist of the Year by Americans for Safe Access, the world’s largest medical cannabis advocacy organization.
D. Hodes, Cannabis Science and Technology3(4), 14–27 (2020).