How to Choose Your Cannabis Extraction Method Including Pros & Cons for Commercial Purposes

While each extraction method offers its unique advantages and applications, the optimal blend of these merits in the broader context of your requirements – what you intend to accomplish – determines the choice of the method. 

Importance of Choosing the Right Extraction Method

Rising awareness on the umpteen health benefits of cannabis has made many countries across the world legalise it. More so after the United Nations removed cannabis and its resin from the “most dangerous drug” list of the 1961 Single Convention on Narcotic Drugs in December 2020.  

This presents an excellent opportunity for cannabis businesses. Extraction of the desirable compounds from the cannabis plants is the first step. These extracts form the basis of the final products that are used for medicinal or recreational purposes.

Multiple methods are in vogue for cannabis extraction. Choosing the most appropriate method involves striking a balance between a host of quality, operational, regulatory, and labour factors. This article discusses some of the most popular methods with a view to help you choose the most appropriate one based on your requirements and resources.

Health Benefits of Cannabis

Cannabidiol (CBD) is among the most in-demand cannabinoids (compound in cannabis) on account of its medicinal properties. Extractors look to maximise CBD content of their products while striving to retain traces of terpenes and flavonoids which respectively lend peculiar and desirable aroma and flavour. Legal reasons necessitate the minimising or elimination of tetrahydrocannabinol (THC), another cannabinoid.

Medicinal properties of CBD include its ability to counter: 

• Pain
• Anxiety & Depression
• Mental Illnesses / Psychosis
• Migraines
• Inflammation
• Nausea
• Seizures
• Inflammatory Bowel Disease

Factors for Choosing a Cannabis Extraction Method

Selection of the most compatible method is based on striking an optimal mix of the following factors:

• Quality roughly encompasses the objectives of post-processing – CBD, THC, terpenes, and flavonoids content.
• Cost Considerations such as utility expenses, yield, and efficiency.
• Regulatory Requirements on the type of solvents used, permitted solvent levels in the final product.
• Environmental Factors such as the disposal of solvents and other materials used for extraction.
• Safety is related to the toxicity and explosive potential of solvents. Explosion-proofing is necessary for pressure vessels, if these are used.
• Labour Requirements or the degree of labour intensiveness inherent in the extraction method.

Extraction Methods

Solvent-based and Solvent-free are the two broad types of cannabis extraction methods. The latter do not use solvents such as supercritical carbon dioxide (sCO₂) or ethanol, and are suited for small batch production. The latter have higher production rates. 

Following are among the popular methods for cannabis extraction:

• Supercritical Fluid Extraction (SCFE) commonly employs supercritical carbon dioxide (sCO2) to extract the product at high pressure and separates it out at low.
  
  Pressure control enables largely targeted extraction. Low operational temperatures prevent thermal distortion of heat sensitive products. Carbon dioxide recirculation makes it a non-polluting technology. Plus, the availability and rates of CO2 keep operational expenses in check.
  
  Initial investment is high as the technology relies on pressure vessels and intricate temperature/pressure control systems. Post extraction processing is necessary to achieve distillates and isolates. Besides, operations are complex.
  
  
• Cryogenic Ethanol Extraction is a technology that dissolves the required product that is extracted from the cannabis biomass in cold ethanol (solvent) at around -40 deg-C in a centrifuge. Filtration and evaporation segregate the product(s) from ethanol.
  
  Speed and quality are the primary USPs of this method. The batch time is reduced to minutes using a brute force extraction for cryo ethanol is a powerful solvent. Ethanol at cold temperatures does not extract lipids, fats, and waxes, thereby eliminating one entire post processing operation. And, as with all solvent-based methods, extract purity is more predictable.
  
  Operational costs and statutory compliances due to large volumes of ethanol are the limiting factors for this method for it uses chilling and evaporating systems, ethanol recovery mechanisms, and centrifuges. Some amount of post processing is for distillates and isolates.

• Hydrocarbon Extraction dissolves the product in butane, propane, or a butane-propane mix (the solvents). After dewaxing, the solvent-product mix is subjected to centrifugation and winterisation before evaporating off the solvent.  
  
  Full spectrum extraction or the extraction of all desired cannabinoids is possible due to propane and butane having lower boiling points. But this means the extract contains traces of THC as well. Yields are high but solvent residues persist in the extract and the use of heat for separation can distort heat sensitive products.  
  
  
• Cold Press Extraction is a solvent-free method that crushes the chilled cannabis plant or seeds under very high pressure. Residues are filtered out. Extract composition is not selective making them useful for wellness products but not for medicinal applications. Besides, yields are low and scalability is a challenge. 
  
  
• Ice Water Extraction relies on mechanical separation (agitation) of cannabis raw material packed in mesh bags and placed inside icy water – no solvents. Here again, there is little control over purity. Although more labour intensive vis-à-vis solvent-based methods, it throws up fewer operational hazards and is relatively economical.  

Choosing the Appropriate Method 

Methods such as supercritical CO2 extraction and cryogenic ethanol extraction offer excellent control over the composition of the final product as is needed in the pharmaceutical and food industry. These should be your method of choice if consistent output quality is your prime concern, for it will more than make up for the high inputs on cost and compliance. When data track and trace is part of the automation for these methods, process optimisation is possible. 

Regulations for recreational cannabis products can be more flexible with their composition requirements. You can employ the ice water and cold press extraction methods for such applications provided labour supply is amply available. The same is broadly true for hydrocarbon extraction.