It’s a fact that the cannabis industry as a whole is growing at an impressive clip. Two main drivers are at work with regard to advances in the medicinal cannabis processing sector. Research into potential therapeutic value has spawned the development of higher efficiency and quality control systems in cannabis processing, testing, and product manufacturing. This trend will continue as clinical data flows in and FDA-approved therapies flow out to the marketplace. Regulatory approval will facilitate more complete and universal guidelines for these processes, which in turn will necessitate advanced equipment to meet demands. These drivers are not mutually exclusive.
Manufacturers and refurbished equipment dealers are keen to these factors, developing new products and adaptations of existing lines in order to provide solutions to the growing and maturing industry. Many technologies have been picked from other fields such as the agricultural and petroleum industries. Others have been adapted from testing and quality control areas such as food safety and toxicology. More recent trends such as the desire to obtain enriched CBD preparations over extracts and oils have led to specified equipment and methods accordingly.
Medical marijuana processing facilities may have rigorous quality control systems in place to conform to GMP and state and federal testing agencies. These may include SOPs for growth, pest control, moisture and metal analysis, as well as potency testing and product safety.
Cannabis Milling and Grinding
Post growth and harvesting, plant material is typically trimmed to remove excess stems and leaves which are typically low in bioactive ingredients (cannabinoids). This results in flowers high in cannabinoid content and ripe for further downstream processing. Material grinders, including those with exchangeable screens or sieves, provide the means to generate and specify fine particles ideally suited for the extraction phase.
Hemp grows in stalks and has a much lower percentage of flower to total plant mass than traditional marijuana. Thus, more robust equipment is used for cutting and crushing of hemp fiber and leaf material. Advances in equipment have boosted the utility and throughput of these devices while providing methods for keeping these mills clean and free from jams. Vendors may offer a range of equipment suited for the scale of processing operation (i.e. 50 l/hr to 85 l/hr or more).
Furthermore, two-stage devices may be available that combine large scale cutting with fine milling to produce precise material ideal for extraction -- directly from raw bulk material. Downstream extraction methods may be impacted by suboptimal cutting and milling, thus decreasing production yields – underlining the importance of this stage of processing.
Cannabis extraction encompasses a broad range of techniques gleaned from a diverse collection of industries. For lab-scale quality and potency testing applications, methods adapted from the food and materials testing fields are applicable. Organic or soluble organic solvents can be used, as well as stepwise procedures such as QuEChERS or super fluid extraction (SFE), to achieve consistent results depending on the testing criteria and tolerance to extraction materials. Larger-scale extraction operations may make use of systems designed for such volume in the agriculture or petroleum industries. Again, solvent or supercritical fluid extraction using processing scale equipment is applicable for these applications.
Post extraction processing methods make use of evaporation and distillation devices to remove unwanted solvents and concentrate the product. Techniques may include: rotary evaporation, fractional distillation, short path distillation, and derivations thereof. Several stages of processing may be required depending on the product and the method of enrichment (i.e. CBD enrichment through organic solvent extraction).
Further fractionation of extracts can be performed by analytical and preparative HPLC -- the scale of which depends on the application. Identification and quantification of specific compounds (cannabinoids) or a profile of constituents may be performed using an existing analytical HPLC system with customized methods or a dedicated built-for-purpose system. Depending on the methods and scale, a further solvent removal or exchange may be necessary for the final preparation.
Cannabis Processing and Outlook
Detailed descriptions and associated products from the extraction and testing phases of cannabis processing will be the subjects of dedicated Cannabis Laboratory newsletters in the coming months. Refinements in processing methods and technologies will continue to be driven by therapeutic development and market forces, however, advancements in fundamental knowledge of the cannabis plant will have widespread implications on the industry as a whole. An example of a “disruptive” advancement is the recent sequencing of complete cannabis genomes. Further understanding and stratification of the molecular underpinnings of cannabinoid production will lead to even cleaner and more efficient production of discrete compounds for medicinal purposes and beyond.