With the new cannabis 2.0 products hitting the markets some of you might be wondering, how do we go from plant to these products? Although Cannabis extraction methods comes in many different forms, here we will be focusing on the main 4 categories: Ethanol, Hydrocarbon, CO2 and solvent-less.
What exactly is cannabis extraction?
Cannabis extraction is the process by which wanted components of the cannabis are extracted or taken out of the plant material to create a specific concentrated product. Cannabis plant material consists of sesquiterpenes, terpenes, cannabinoids, flavonoids, pigments, sugars, chlorophyll, fats, waxes, lignin, pectin, starches, vitamins, nutrients, phytonutrients and cellulose. There are many variables within each extraction method that can be manipulated to change the constituents of the product depending on how the consumer likes their product.
These methods of extraction can be configured in two main categories, open loop and closed loop. The main difference between these two systems, is that a closed loop system recycles the solvent within the system. This recycled solvent is usually reused in future extractions.
1. Ethanol Extraction
To extract using ethanol, plant material is soaked in an Ethanol bath. The mixture is then filtered and evaporated leaving cannabis extract. This method also dissolves chlorophyll into the mixture which creates a bitter taste on the product. Chlorophyll however, can be greatly reduced in the product if extremely low temperatures are used. You may have heard of the term winterization, (Winterization: is when the extraction is completed at sub-zero temperatures <-20 ° C). This is done to remove fats and waxes from the extract.
Why is this important? These fats and waxes will leave residues, decrease quality of flavor, increasing likelihood of a harsh smoke. On a safety note, this method of extraction is extremely dangerous due to the flammability of ethanol.
2. Hydrocarbon Extraction
Usually using the hydrocarbons propane or butane and sometimes a mixture of the two, cannabis plant material is placed into a holding container with the hydrocarbons added. The hydrocarbon dissolves the cannabinoids, terpenes, and other constituents into a concentrated product. This extract requires further purification due to the risk of residual hydrocarbons. Generally, this is done by slightly heating and then vacuum purging the extract. Dewaxing can be done using hydrocarbons as well, (Dewaxing: is competing hydrocarbon extraction at extremely low temperatures with the liquid extract put through a filter that collects the fats and waxes). Be extremely careful with this extraction method. The risk is due to the explosive properties of hydrocarbons and has been known to cause explosions for people experimenting at home. This method of extraction can produce many products like; shatter, wax, butter, BHO, and Live Resin
3. C02 Extraction
When extracting with CO2, plant material is placed into a canister, liquid C02 pumped in, then the extract is collected. CO2 dissolves the components as with other solvents but is less risky and has great yields. Temperatures, length of extraction time, and other factors can be all be adjusted for extracting specific properties of the plant. The extract still contains waxes, pigments and cell-wall fragments which can be removed by either winterization or dewaxing. You may have heard of the terms super critical or sub-critical. This is referencing the temperatures of the extraction. Sub-critical is colder than super critical, but also is done at lower pressures. This environment is less volatile, increasing the retention of volatile terpenes and cannabinoids. There are drawbacks to this like longer extraction time and smaller yield.
4. Solvent-less Extraction
Solvent-less extraction uses temperatures and/or physical agitation to extract components of the cannabis plant. Trichomes, or resin glands found on the cannabis plant, are highly concentrated with cannabinoids. These trichomes are what are being extracted from the plant material. Some examples of solvent-less extraction:
- Cold Pressing: Similar to juicing, the plant material is pressed in cold temperatures extracting the cannabinoids and other components from the plant.
- Bubble/ice water extraction: Plant material is placed into screen bags of ice water which is then agitated removing the trichomes.
- Dry sift extraction: Dry plant material sifted over screens separating leaf from resin glands.
Ketama drums: The ancient process of dry sifting where cannabis is placed on a screen over a drum and agitated with sticks- Rosin Pressing: This is when plant material placed in a screened bag and pressed between two heated plates which extracts the resin as a product called rosin.
- Infusion: Cannabis material is soaked in oil while adding heat. This extracts oil soluble plant material into the oil making it infused with cannabis.
- Distillation: Although is generally done with solvent extractions, is not a solvent process. Distillation is the act of boiling extract and collecting the purified components at specific temperatures.
With so many variations and no end to subjectivity, there are countless options for products to be developed in the future. The type of product and how to apply is going to vary drastically among individuals. Hopefully this helped in giving you the knowledge to make informed choices on the products you wish to choose and the level of efficacy on your medical cannabis.
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Written By: Matthew Butt – Cannabinoid Therapy Educator, CHC Mount Pearl – Newfoundland.