Challenges with Process Scale Up in Cannabis/Hemp Extraction

By Darwin Millard

What makes scaling up your process so difficult?

There are many factors that can lead to the challenges people face when scaling up their processes. These challenges are not unique to the cannabis/hemp industry, but they are exacerbated by the consequences generated from decades of Reefer Madness. In my time operating in the cannabis/hemp space, 15+ years, I have seen established equipment vendors and sellers of laboratory supplies, like Sigma-Aldrich (now Millipore-Sigma), Fisher-Scientific, Cerilliant, Agilent, and others, go from reporting individuals inquiring about certified reference materials to setting up entire divisions of their companies to service the needs of the industry. Progress. But we are still a fledgling marketplace facing many challenges. Let’s look at a few specific to process scale up.

Darwin Millard will deliver a presentation on this topic during the Cannabis Extraction Virtual Conference on June 29. Click here to learn more.Equipment Availability: Lack of available equipment at larger and larger process scales can severely impact project timelines. Making not only equipment acquisition difficult, but also limiting the number of reputable equipment manufacturers you can work with.

Non-Linear Expansion: NEVER assume your process scales linearly. Perhaps one of the most avoidable mistakes during process scale up. You will quickly find that for many processes you cannot just put in a larger unit and expect a proportional increase in output. This is because as process equipment increases so to must utilities and other supporting infrastructure, but not only that, process vessel geometry, proportions, and design are contributing factors to process efficiency as your scale of operations increases.

Hazardous Material Quantities: Just as important to the process as the equipment are the solvents and reagents used. As your scale of operations increases so does your demand and production of hazardous materials; solvents including carbon dioxide (CO2), ethanol, and liquid petroleum gases (LPG) like Butane and Propane are obvious hazards, but so too are the refrigerants used in the chillers, fuels used to power generators, steam created to heat critical systems, and effluents and wastewater discharged from the process and supporting systems. Not every municipality wants thousands of gallons of flammable substances and hazardous waste being generated in their backyard…

Contractor/Vendor Misrepresentation: Finding out in the middle of you project that your contractor or equipment vendor has never set up a system at this scale before is never a good feeling. Unfortunately, contractor and vendor misrepresentation of qualifications is a common occurrence in the cannabis/hemp space.

If all this was not bad enough, all too often the consequences of improper planning and execution are not felt until your project is delayed or jeopardized due to misallocation of funds or undercapitalization. This is especially true when scaling up your production capacity. Now let’s look at some ways to avoid these mistakes.

The Rule of 10

Construction drawings for a piece of process equipment.

When scaling up your process, NEVER assume that a simple linear expansion of your process train will be sufficient. It is often the case that process scale up is non-linear. Using the Rule of 10 is one way of scaling up your process through a stepwise iterative approach. The Rule of 10 is best explained through an example: Say you are performing a bench-top extraction of a few grams and want to scale that up to a few thousand kilograms. Before jumping all the way to your final process scale, start by taking a smaller jump and only increase your bench-top process by a factor of 10 at a time. So, if you were happy and confident with your results at the tens of grams scale, perform the same process at the hundreds of grams scale, then the thousands of grams scale, tens of kilograms scale, and so forth until you have validated your process at the scale of operations you want to achieve. By using the Rule of 10 you can be assured that your process will achieve the same yields/results at larger and larger scales of operation.

Scaling up your process through an iterative approach allows you to identify process issues that otherwise would not have been identified. These can include (but by no means should be considered an exhaustive list) improper heat transfer as process vessels increase in size, the inability to maintain process parameters due to inadequately sized utilities and/or supporting infrastructure, and lower yields than expected even though previous iterations were successful. However, this type of approach can be expensive, especially when considering custom process equipment, and not every processor in the cannabis/hemp space is going to be in the position to use tools like the Rule of 10 and instead must rely on claims made by the equipment vendor or manufacture when scaling up their process.

The Cannabis/Hemp Specific Process Equipment Trap

How many times have you heard this one before: “We have a piece of process equipment tailor-made to perform X,Y,Z task.”? If you have been around as long as I have in the cannabis/hemp space, probably quite a few times. A huge red flag when considering equipment for your expansion project!

Unless the equipment manufacturer is directly working with cannabis/hemp raw materials, or with partners who process these items, during product development, there is no way they could have verified the equipment will work for its purported use.

A good example of this are ethanol evaporation systems. Most manufacturers of evaporators do not work with the volumes of ethanol they claim their systems can recover. So how did they come up with the evaporation rate? Short answer – Thermodynamics, Heat Transfer, and Fluid Mechanics. They modeled it. This much surface area, plus this much heat/energy, with this much pressure (or lack thereof), using this type of fluid, moving through this type of material, at this rate of speed, gets you a 1000-gal/hr evaporator or some other theoretical value. But what is the real rate once an ethanol and cannabis/hemp solution is running through the system?

For a straight ethanol system, the theoretical models and experimental models are pretty similar – namely because humans like alcohol – extensive real-world data for ethanol systems exist for reference in designing ethanol evaporators (more accurately described as distillation systems, i.e. stills). The same cannot be said for ethanol and cannabis/hemp extract systems. While it is true that many botanical and ethanol systems have been modeled, both theoretically and experimentally, due to prohibition, data for cannabis/hemp and ethanol systems are lacking and the data that do exist are primarily limited to bench-top and laboratory scale scenarios.

So, will that 1000-gal/hr evaporator hit 1000-gal/hr once it is running under load? That’s the real question and why utilizing equipment with established performance qualifications is critical to a successful process scale up when having to rely on the claims of a vendor or equipment manufacturer. Except this is yet another “catch 22”, since the installation, operational, and performance qualification process is an expensive endeavor only a few equipment manufacturers servicing the cannabis/hemp market have done. I am not saying there aren’t any reputable equipment vendors out there; there are, but always ask for data validating their claims and perform a vendor qualification before you drop seven figures on a piece of process equipment on the word of a salesperson.

Important Takeaways

Improper design and insufficient data regarding process efficiencies on larger and larger scales of manufacturing can lead to costly mistakes which can prevent projects from ever getting off the ground.

Each aspect of the manufacturing process must be considered individually when scaling your process train because each element will contribute to the system’s output, either in a limiting or expansive capacity.

I go further into this topic in my presentation: Challenges with Process Scale Up in the Cannabis/Hemp Industry, later this month during Cannabis Industry Journal’s Extraction Virtual Conference on June 29^th, 2021. Here I will provide real-world examples of the consequences of improper process scale up and the significance of equipment specifications, certifications, and inspections, and the importance of vendor qualifications and the true cost of improper design specifications. I hope to see you all there.

Until then. Live long and process.

May 13, 2021

Defining Hemp: Classifications, Policies & Markets, Part 2

By Darwin Millard

2 Comments

In Part 1 of this series we answered the question: What is “hemp”; and addressed some of the consequences of defining “hemp” as a thing. In Part 2, I will explore this topic in more detail and provide some commonsense definitions for several traditional hemp products based on a classification approach rather than separating “cannabis” from “hemp”.

Classifications, Specifications, and Test Methods – Establishing Market Protections for Hemp Products Through Standardization

Does making a distinction between “hemp” and “cannabis” make it easier to protect the interests of the seed and fiber markets?

On the face of it, this question seems obvious. Yes, it does.

Up to this point in history, the bifurcation of the cannabis plant into resin types and non-resin types has served to provide protections for the seed and fiber markets by making it easier for producers to operate, since the resins (the scary cannabinoids, namely d9-THC) were not involved. Today, however, the line in the sand, has been washed away, and “hemp” no longer only refers to non-resin producing varieties of the cannabis plant.

The structure of cannabidiol (CBD), one of 400 active compounds found in cannabis.

As more and more hemp marketplaces come online with varying limits for d9-THC the need for standardization becomes even more pressing. Without standardization, each marketplace will have its own requirements, forcing businesses looking to sell their products in multiple jurisdictions to comply with each region’s mandates and adds a significant level of burden to their operations.

Providing an internationally harmonized definition for hemp is an important first step but allowing the d9-THC limit to vary from jurisdiction to jurisdiction has some unintended (or intended) consequences (#NewReeferMadness). These discrepancies between legal marketplaces will inevitably lead to the establishment of global trade regions; where, if your product cannot meet the definition of “hemp” in that region, then you could effectively be barred from participating in it.

A process which has already started. Harmonizing around 0.3% is great for the US, Canada, and European Union, but what about other stakeholders outside of these markets?

And, at what point does the conflict of hemp from one region with a d9-THC content of 0.3% and hemp from another region with a d9-THC content of 1% being sold into the same market become a problem?

Perhaps a better long-term solution for protecting the market interests of “hemp product” stakeholders would be to establish specifications, such as identity metrics, total cannabinoid content, especially d9-THC, and other quality attributes which have to be verified using test methods for a product to be classified as “hemp”. This system of standards (classifications, specifications, and test methods) would allow for more innovation and make it significantly easier for cannabis raw materials that meet these specifications to find a use rather than being sent to the landfill. Bolstering advancements and opening the door for more market acceptance of the cannabis plant, its parts, and products.

An Alternative Approach to Defining Hemp

Below are some proposed definitions related to common terminology used in the hemp marketplace based on the concept that there are no hemp plants, there are only cannabis plants that can be classified as hemp, and hemp products are simply cannabis products that meet certain specifications to allow them to be classified and represented as hemp.

Hemp, n—commercial name given to a cannabis plant, its parts, and products derived therefrom with a total d9-THC content no more than the maximum allowable limit for the item in question. (Maybe not the best definition, but it makes it clear that not only does the limit for d9-THC vary from jurisdiction to jurisdiction it varies from product type to product type as well.)
Hemp flower, n—commercial name for the inflorescence of a cannabis plant that can be classified as hemp.
Hemp seed, n—commercial name for the seeds of a cannabis plant which are intended to be used to grow another cannabis plant that can be classified as hemp.
Hempseed, n—commercial name for the seeds of a cannabis plant which are intended to be used as food or as an ingredient in food.
Hemp seed oil, n—commercial name for the oils expressed from the seeds of a cannabis plant.
Hemp seed cake, n—commercial name for the solid material byproduct generated during the expression of the oil from the seeds of a cannabis plant.
Hemp flour/meal/dietary-fiber, n—commercial name for the powdered seed cake of a cannabis plant intended to be used as a food or as an ingredient in food with a protein content no more than 35% by weight.
Hemp protein powder, n—commercial name for the powdered seed cake of a cannabis plant intended to be used as a food or as an ingredient in food with a protein content between 35% and 80% by weight.
Hemp protein isolate, n—commercial name for the powdered seed cake of a cannabis plant intended to be used as a food or as an ingredient in food with a protein content above 80% by weight.
Hemp fiber, n—commercial name for the cellulosic-based natural fibers of a cannabis plant.
Hemp shives, n—commercial name for the hurd of a cannabis plant which have been processed to defined specifications.
Hempcrete, n—commercial name for a solid amalgamation of various aggregates and binders, typically comprised of the hurd (shives) of a cannabis plant and lime.

The d9-THC limits for each product were purposefully omitted because these specifications still need to be defined for each product type. Leaving the d9-THC limit up to each authority having jurisdiction, however, is not the answer. It is fine if you comply with a lower d9-THC limit and want to sell into a market with a higher d9-THC limit, but what do you do if you are above the limit for the market you want to sell into? For now, you lose out on potential revenue.

I am not advocating that everyone starts selling “hemp” as “cannabis,” or vice versa, far from it. I am advocating for a more commonsense and inclusive approach to the marketplace though. One that would allow for the commercialization of materials that would normally be going to waste.

To me it is simply logical. There are no hemp plants, there are only cannabis plants that can be classified as hemp. There are no hemp products, there are only cannabis products that can be classified as hemp. In order for a cannabis product to be marketed, labeled, and sold as a hemp product, i.e. to be classified as a hemp, it would need to meet a set of specifications and be verified using a set of test methods first. But fundamentally the product would be a cannabis product being certified as “hemp”. And that is the shift in thinking that I am trying to get across.

Exclusionary Actions – Disenfranchising Stakeholders

The cannabis plant is an amazing plant and to fully capitalize on the potential of this crop we have to start allowing for the commercialization of cannabis raw materials that are not controlled by the UN Single Conventions, i.e. the seeds, stalks, roots, and leaves when not accompanied by the fruiting tops or the resin glands. Not to do so disenfranchises a significant number of stakeholders from participating in established legal avenues of trade for these goods. A concept proposed and endorsed the ASTM D37 in the published standard D8245-19: Guide for Disposal of Resin-Containing Cannabis Raw Materials and Downstream Products.

If you are stakeholder in the hemp marketplace, you may feel threatened by the idea of the market getting flooded with material, but how are the demands of the so called “green economy” going to be met without access to more supply? Organic hemp seed for food production is scarce but there is plenty of conventional hemp seed for the current demand, but what happens when hempmilk is positioned to displace soymilk in every major grocery store? To feed the growth of the human population and allow for a transition to a truly “green economy,” we need to ensure that the policies that we are putting in place are not excluding those looking to participate in the industry and disenfranchising stakeholders from burgeoning marketplaces, nor alienating a segment of the marketplace simply because their plant cannot be classified as “hemp”.

Until next time…

Live long and process.

April 29, 2021

Defining Hemp: Classifications, Policies & Markets, Part 1

By Darwin Millard

2 Comments

What is “hemp”?

The word “hemp” has many meanings. Historically the term has been used as the common name for the Cannabis sativa L. plant. Just like other plants, the cannabis plant has two names, a common name, hemp, and a scientific name, Cannabis sativa L. After the ratification of the UN Single Conventions on Narcotic Drugs and Psychotropic Substances, in 1961 and 1972 respectively, the term started to be used to distinguish between resin producing varieties of the cannabis plant and non-resin producing varieties of the cannabis plant. Nowadays the term is generally used to refer to cannabis plants with a delta-9-tetrahydrocannabinol (d9-THC), a controlled substance, content equal to or less than the maximum allowable limit defined by each marketplace.

Tetrahydrocannabinol (THC), just one of hundreds of cannabinoids found in cannabis.

In the United States and Canada, the limit is defined as 0.3% on a dry weight bases, and until November 2020, in the European Union, the limit was defined as 0.2%. After years of effort the “hemp” industry in Europe was successfully able to get the limit raised to 0.3% to be in line with the United States and Canada – creating the largest global trade region for hemp products. But there exist several marketplaces around the world where, either through the consequences of geographic location or more progressive regulations, the d9-THC content in the plant can be substantially higher than 0.3% and still considered “hemp” by the local authority.

To address these variances, ASTM International’s Technical Committee D37 on Cannabis has been working on a harmonized definition of hemp, or industrial hemp, depending on the authority having jurisdiction, through the efforts of its Subcommittee D37.07 on Industrial Hemp. The following is a proposed working definition:

hemp, n—a Cannabis sativa L. plant, or any part of that plant, in which the concentration of total delta-9 THC in the fruiting tops is equal to or less than the regulated maximum level as established by an authority having jurisdiction.

Discussion: The term “Industrial Hemp” is synonymous with “Hemp”.

Note: Total delta-9 THC is calculated as Δ⁹-tetrahydrocannabinol (delta-9 THC) + (0.877 x Δ⁹-tetrahydrocannabinolic acid).

This definition goes a long way to harmonize the various definitions of hemp from around the world, but it also defines “hemp” as a thing rather than as a classification for a type of cannabis plant or cannabis product. This is a concept rooted in the regulatory consequences of the UN Single Conventions, and one I strongly disagree with.

The definition also leaves the total d9-THC limit open-ended rather than establishing a specified limit. An issue I will address further in this series.

Can “hemp products” only come from “hemp plants”?

If you are an invested stakeholder in the traditional “hemp” marketplace, you would say, yes.

But are there such things as “hemp plants” or are there only cannabis plants that can be classified as “hemp”? (The definition for hemp clearly states that it is a cannabis plant…)

There is no distinction between the cannabinoids, seeds, and fibers derived from a cannabis plant that can be classified as “hemp” and those derived from a cannabis plant that cannot. The only difference is the word: “cannabis,” and the slew of negative connotations that come along with it. (Negative connotations that continue to be propagated subconsciously, or consciously, whenever someone says the “hemp plant” has 50,000+ uses, and counting, and will save the world because it’s so green and awesome, but not the “cannabis plant”, no that’s evil and bad, stay away! #NewReeferMadness)

The declaration that “hemp products” only come from “hemp plants” has some major implications. “Hemp seeds” can only come from “hemp plants”. “Hemp seed oils” can only come from “hemp seeds”. “Hemp fibers” can only come from “hemp plants”. Etc.

What does that really mean? What are the real-world impacts of this line of thinking?

Flat out it means that if you are growing a cannabis plant with a d9-THC content above the limit for that plant or its parts to be classified as “hemp”, then the entire crop is subjected to the same rules as d9-THC itself and considered a controlled substance. This means that literal tons of usable material with no resin content whatsoever are destroyed annually rather than being utilized in a commercial application simply because a part or parts of the plant they came from did not meet the d9-THC limit.

Some of the many products on the market today derived from hemp

It is well known that d9-THC content is concentrated in the glandular trichomes (resin glands) which are themselves concentrated to the fruiting tops of the plant. Once the leaves, seeds, stalks, stems, roots, etc. have been separated from the fruiting tops and/or the resin glands, then as long as these materials meet the authority having jurisdiction’s specifications for “hemp” there should be no reason why these materials could not be marketed and sold as “hemp”.

There are several reasons why a classification approach to “hemp plants” and “hemp products” makes more long-term sense than a bifurcation of the “cannabis” and “hemp” marketplaces, namely from a sustainability aspect, but also to aid in eliminating the frankly unwarranted stigma associated with the cannabis plant. #NewReeferMadness

That said, say you are a producer making shives from the stalks of cannabis plants that can be classified as “hemp” and then all of a sudden, the market opens up and tons of material from cannabis plants that cannot be classified as “hemp,” that was being sent to the landfill, become available for making shives. Would you be happy about this development? Or would you fight tooth and nail to prevent it from happening?

In this segment, we looked at the history of the term “hemp” and some of the consequences from drawing a line in the sand between “cannabis” and “hemp”. I dive deeper into this topic and provide some commonsense definitions for several traditional hemp products in Part 2 of Defining Hemp: Classifications, Policies & Markets.

March 3, 2021

Navigating Compliance: Practical Application of Fit-For-Purpose

By Darwin Millard

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What is “fit-for-purpose?” Fit-for-purpose is an established best practice used in several major industries, like information technology, pharmaceuticals, agriculture and inventory management. It is a concept that aligns infrastructure and systems specifications with desired outputs – be that product, service or bottom line. When applied to a cannabis plant, its parts, products and associated processes, it can streamline regulatory framework development, implementation and compliance.

Fit-for-purpose is simply a series of logic questions you ask yourself to determine what business practices you should implement and the regulatory framework in which you must comply. What are you making? Who is it for? Where will it be sold? All this impacts how you would cultivate, process, handle and store a cannabis plant, its parts and products regardless of the type of cannabis plant. The fit-for-purpose concept is a tool that can be applied to any scenario within the cannabis/hemp marketplace. Take for instance, sustainability: a practical example would be to design cultivation standards that are “fit-for-purpose” to the climatic region in which the plants are grown – allowing any type of cannabis plant grown anywhere in the world to meet specifications regardless of the method of production.

There is no “special sauce” here. All fit-for-purpose does is get you to ask yourself: “Are the protocols I am considering implementing ‘fit/appropriate’ to my situation, and if not, which protocols are more ‘fit/appropriate’ based on the products I am making, the target consumer and marketplace in which the products are to be sold?”“Fit-for-purpose is a powerful concept that can be used for simplifying regulatory framework development, implementation and compliance”

A non-cannabis/hemp example of fit-for-purpose could be a scenario where a banana producer wants to implement a data management system into their cultivation practices to better track production and yields. There are many data management systems this banana producer could implement. They could implement a data management system like that of big pharma with multiple levels of redundancy and access control related to intellectual property and other sensitive data. They could also implement a data management system used for tracking warehouse inventory; it cannot exactly capture everything they need but it is better than nothing. Neither example is really “fit/appropriate” to the banana producer’s needs. They need something in between, something that allows them to track the type of products they produce and the data they want to see in a way that is right for them. This idea is at the core of the fit-for-purpose concept.

Applying Fit-for-Purpose

So how do we apply fit-for-purpose to the cannabis/hemp marketplace? Fit-for-purpose reduces the conversation down to two questions: What products are you planning to make and how do those products affect your business practices, whether that be cultivation, processing, manufacturing or compliance. The point being the products you plan to produce determine the regulations you need to follow and the standards you need to implement.

Growers can use it to guide cultivation, harvesting, handling and storage practices. Processors and product manufacturers can use it to guide their production, handling, packing and holding practices. Lawmakers can use it to guide the development, implementation and enforcement of commonsense regulations. This is the beauty and simplicity of fit-for-purpose, it can be applied to any situation and related to any type of product.

Let us look at some practical examples of fit-for-purpose for cultivators and processors. Cultivators have three main areas of focus, growing, harvesting and storage, whereas processors and product manufacturers have it a little more complicated.

Cultivation of a Cannabis Plant

Growing

Requirements for growing a cannabis plant, including those that can be classified as “hemp”, should be dictated by the product with the strictest quality and safety specifications. For example, growing for smokable fruiting tops (i.e. the flowers) may require different cultivation techniques than other products. You may not want to apply the same pesticides or growth additives to a cannabis plant grown for smokable fruiting tops as you would to a cannabis plant grown for seed and fiber.

Harvesting

The next point is important – harvesting and handling requirements should be agricultural, period. Except for those products intended to be combusted or vaporized and then inhaled. Following our previous example, smokable fruiting tops may require different harvesting techniques than other products, especially if you are trying to maintain the aesthetic quality of these goods. You may choose a different harvesting technique to collect these fruiting tops than you would if primarily harvesting the seed and fiber and thinking of the leftover biomass as secondary.

Storage

When considering the products and their storage, you need to consider each one’s quality and safety specifications. One product may have a temperature specification, whereas another may have a humidity specification. You need to make sure that you store each product according to their individual quality and safety specifications. Then consider the products with the highest risks of diversion and potentially if you need to implement any extra protocols. Continuing our example – smokable fruiting tops, whether classifiable as “hemp” or not, pose a higher risk of theft than seeds or fiber and may require additional security measures depending on the authority having jurisdiction.

Processing and Manufacturing Operations

When applying fit-for-purpose to processing and manufacturing operations, first you must choose the products you want to make and specify the intended use for each product. This allows you to identify the quality and safety requirements and the potential for diversion for each good. Which in turn allows you to specify your manufacturing, processing and handling protocols for each product related to their quality and safety requirements. Then those specific products with higher risks of diversion requiring extra protocols to be put into place depending on local regulations and/or internal risk assessments, should be considered and your practices modified, as necessary.

Commonsense Regulations

Image if regulations governing a cannabis plant, its parts, products and associated processes were based on the intended use rather than a set of attributes that vary from jurisdiction to jurisdiction. It is complicated enough for regulators to think about a cannabis plant or cannabis product without having to worry about if that cannabis plant or cannabis product can be classified as “marijuana” or “hemp.” Fit-for-purpose removes this complication and simplifies the debate.

Using a fit-for-purpose approach eliminates the need to think about the molecular constituents and focuses the conversation on the intended use rather than one or two specific molecules – in this case, d9-THC, the boogie-man cannabinoid. Considering the intended use promotes consumer and environmental health and safety by allowing operators and regulators to focus on what is most important – quality and safety instead of whether something is “marijuana” or “hemp.”

This idea is what drives the real impact of fit-for-purpose. It creates a path forward to a one plant solution. We have where we are now – with “marijuana” and “hemp” – and where we want to get to – cannabis. It is all one plant with many different applications that can be used to create different commercial products. Fit-for-purpose helps bridge the gap between where we are now and where we want to get to and allows us to start thinking about “marijuana” and “hemp” in the same manner – the intended use.

Fit-for-purpose is a powerful concept that can be used for simplifying regulatory framework development, implementation and compliance. Regulations imposed on a cannabis plant, its parts and products should be appropriate to their intended use, i.e. “fit-for-purpose.” This approach challenges the confines of the current draconian bifurcation of the cannabis plant while working within this system to push the boundaries. It creates a path forward to a one plant solution and begs the question: Is the world ready for this novel concept?

February 16, 2021

THC Remediation of Hemp Extracts

By Darwin Millard

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Remediation of delta-9 tetrahydrocannabinol (d9-THC) has become a hot button issue in the United States ever since the Drug Enforcement Agency (DEA) released their changes to the definitions of marijuana, marijuana extract, and tetrahydrocannabinols exempting extracts and tetrahydrocannabinols of a cannabis plant containing 0.3% or less d9-THC on a dry weight basis from the Controlled Substances Act. That is because, as a direct consequence, all extracts and tetrahydrocannabinols of a cannabis plant containing more than 0.3% d9-THC became explicitly under the purview of the DEA, including work-in-progress “hemp extracts” that because of the extraction process are above the 0.3% d9-THC limit immediately upon creation.

The legal ramifications of these changes to the definitions on the “hemp extracts” marketplace will not be addressed. Instead, this article focuses on the amount of d9-THC that is available in the plant material prior to extraction and tracks a “hemp extract” from the point it falls out of compliance to the point it becomes compliant again and stresses the importance of accurate track-n-trace protocols at the processing facility. The model developed to support this article was intended to be academic and was designed to follow the d9-THC portion of a “hemp extract” through the lifecycle of a typical CO2-based extract from initial extraction to THC remediation. A loss to the equipment of 2% was used for each step.

Initial Extraction

For this exercise, a common processing scenario of 1000 kg of plant material at 10% cannabidiol (CBD) and 0.3% d9-THC by weight was modeled. This amount, depending on scale of operations, can be a facility’s total capacity for the day or the capacity for a single run. 1000 kg of plant material at 0.3% d9-THC has 3 kg of d9-THC that could be extracted, purified, and diverted into the marketplace. CO2 has a nominal extraction efficiency of 95%, meaning some cannabinoids are left behind in the plant material. The same can be said about the recovery of the extract from the equipment. Traces of extract will remain in the equipment and this little bit of material, if unaccounted for, can potentially open an operator up to legal consequences. Data for the initial extraction is shown in Image 1.

Image 1: Summary Data Table for Typical CO2-based Extraction of Phytocannabinoids

As soon as the initial extract is produced it is out of compliance with the 0.3% d9-THC limit to be classified as a “hemp extract”, and of the 3 kg of d9-THC available, the extract contains approx. 2.8 kg, because some of the d9-THC remains in the plant material and some is lost to the equipment.

Dewaxing via Winterization and Solvent Removal

Dewaxing a typical CO2 extract via winterization is a common process step. For this exercise, a wax content of 30% by weight was used. A process efficiency of 98% was attributed to the wax removal process and it was assumed that 100% of the loss can be accounted for in the residue recovered from the equipment rather than in the removed waxes. Data for the winterization and solvent recovery are shown in Image 2 and 3.

Image 2: Summary Data Table for Typical Winterization of a CO2 Extract

Image 3: Summary Data Table for Solvent Removal from a CO2 Extract

Two things occur during winterization and solvent removal, non-target constituents are removed from the extract and there is compounded loss from multiple pieces of process equipment. These steps increase the concentration of the d9-THC portion of the extract and produce two streams of noncompliant waste.

Decarboxylation & Devolatilization

Most cannabinoids in the plant material are in their acid form. For this exercise, 90% of the cannabinoids were considered to be acid forms. Decarboxylation is known to produce a mass difference of 87.7%, i.e. the neutral forms are 12.3% lighter than the acid forms. Heat was modeled as the primary driver and a process efficiency of 95% was used for the conversion rate during decarboxylation. To simplify the model, the remaining 5% acidic cannabinoids are presumed destroyed rather than degraded into other compounds because the portion of the cannabinoids which get destroyed versus degrade into other compounds varies from process to process.

Devolatilization is the process of removing low-molecular weight constituents from an extract to stabilize it prior to distillation. Since the molecular constituents of cannabis resin extracts vary from variety to variety and process to process, the extracts were assumed to consist of 10% volatile compounds. The model combines the decarboxylation and devolatilization steps to account for complete decarboxylation of the available acidic cannabinoids and ignores their weight contribution to the volatiles collected during devolatilization. Destroyed cannabinoids result in an amount of loss that can only be accounted for through a complete mass balance analysis. Data for decarboxylation and devolatilization are shown in Image 4.

Image 4: Summary Data Table for Decarboxylation and Devolatilization of a CO2 Extract

As the extract moves along the process train, the d9-THC concentration continues to increase. Decarboxylation further complicates traceability because there is both a known mass difference associated with the process and an unknown mass difference that must be calculated and justified.

Distillation

A two-pass distillation was modeled. On each pass a portion of the extract was removed to increase the cannabinoid concentration in the recovered material. Average data for distilled “hemp extracts” was used to ensure the model did not over- or underestimate the concentration of the cannabinoids in the distillate. The variables used to meet these data constraints were derived experimentally to match the model to the scenario described and are not indicative of an actual distillation. Data for distillation is shown in Image 5.

After distillation, the d9-THC concentration is shown to have increased by 874% from the original concentration in the plant material. Roughly 2.2 kg of the available 3 kg of d9-THC remains in the extract, but 0.8 kg of d9-THC has either ended up in a waste stream or walking out the door.

Chromatography – THC Remediation Step 1

Chromatography was modeled to remove the d9-THC from the extract. Because there are several systems with variable efficiency rates at being able to selectively isolate the d9-THC peak from the eluent stream, the model used a 5% cut-off on the front-end and tail-end of the peak, i.e. 5% of the material before the d9-THC peak and 5% of the material after the d9-THC peak is assumed to be collected along with the d9-THC. Data for chromatography is shown in Image 6.

Image 6: Summary Data Table for d9-THC Removal using Chromatography

After chromatography, a minimum of three products are produced, compliant “hemp extract”, d9-THC extract, and noncompliant residue remaining in the equipment. The d9-THC extract modeled contains 2.1 kg of the available 3 kg in the plant material, and is 35% d9-THC by weight, an increase of 1335% from the distillation step and 11664% from the plant material.

CBN Creation – THC Remediation Step 2

For this exercise, the d9-THC extract was converted into cannabinol (CBN) using heat rather than cyclized into d8-THC, but a similar model could be used to account for this scenario. The conversion rate of the cannabinoids into CBN through heat degradation alone is low. Therefore, the model assumes half of the available cannabinoids in the d9-THC extract are converted to CBN. The entirety of the remaining portion of the cannabinoids are assumed to convert to some form of degradant rather than a portion getting destroyed. Data for THC destruction is shown in Image 7.

Image 7: Summary Data Table for THC Destruction through Degradation into CBN

Only after the CBN cyclization step has completed does the product that was the d9-THC extract become compliant and classifiable as a “hemp extract.”

Image 8: Summary Data Table for Reconciliation of the d9-THC Portion of the Hemp Extract

Throughout the process, from initial extraction to the final d9-THC remediation step, loss occurs. Of the 3 kg of d9-THC available in the plant material only 2.1 kg was recovered and converted to CBN. 0.9 kg was either lost to the equipment, destroyed in the process, attributable to the mass difference associated with decarboxylation, or was never extracted from the plant material in the first place. All of these potential areas of product loss should be identified, and their diversion risk fully assessed. Not every waste stream poses a risk of diversion, but some do; having a plan in place to handle waste the DEA considers a controlled substance is essential. Without a track-n-trace program following the d9-THC and identifying the potential risk of diversion would be impossible. The point of this is not to instill fear, instead the intention is to shed light on a very real issue “hemp extract” producers and state regulators need to understand to protect themselves and their marketplace from the DEA.