Exploring methods of cannabis resin extraction
By Owen Smith
By Owen Smith
In my spring article I chronicled the constitutional challenge for cannabis extraction that I helped bring before the BC Supreme Court earlier this year. The result of the case was the immediate freedom of people authorized under the MMAR to extract cannabis resins from the plant medicines that are better suited for their conditions than smoking dry herb. While this ruling doesn’t extend to their caregivers, it does apply to the 14001 or more patients in B.C. with licences. This order from the judge cannot be appealed until my charges are seen through by a jury in Feb. of 2013. The government has been given 12 months to respond by changing the MMAR program, however, prior responses to court orders have been woefully inadequate. With the tough (and blind) on drug crime agenda of the conservative majority government, it’s hard to expect any better. In the meantime it seems appropriate to help patients utilize this new opening in the law by describing some cannabis extracts and how they are made.
The judge’s decision instantly made available all substances listed under schedule 2 of the CDSA2 (fig. 1) which includes naturally produced cannabis resin, THC, CBD, CBN as well as synthetically produced Nabilone, Pyrahexyl, and DMHP. While I will briefly cover the synthetics, I will focus mostly on the natural products as they are effective, safe, and accessible. The methods used to extract natural products are simple when compared to synthetics, yet require some special attention to produce consistent, clean, and potent medicine. A more concentrated form of cannabis resin requires the patient to consume less to obtain the desired effects. While concentrates make it easier to increase dosage for serious conditions, this may make it easier to consume more than one desires, though any undesired effects will be short lived and not life threatening.
DMHP (Dimethylheptylpyran) is a synthetic analogue of THC, which was invented in 1949 during attempts to elucidate the structure of Δ9-THC3, the most common component of cannabis. It is a pale yellow viscous oil which has a higher lipophilicity (ability to dissolve in fats, oils) than that of THC itself. A study performed on cats showed DMHP produces similar analgesic and anticonvulsant effects to THC, only stronger and with weaker psychological effects.4 DMHP is metabolised in a similar manner to THC, producing the active metabolite 11-hydroxy-DMHP in the liver, however it was found to have a longer duration of action.
DMHP was investigated by the U.S. military chemical weapons program in the Edgewood Arsenal experiments as a possible non-lethal incapacitating agent.5 Research was discontinued when high doses were found to cause hypotension and the drug became overshadowed by other incapacitating agents such as BZ.6 While there is little likelihood that someone would attempt to make DMHP for their own medical purposes, it is a curious turn that this substance may now become an instrument of peace rather than war.
The next synthetic on the list, Pyrahexyl, a THC homologue (similar in structure) first made available to clinical researchers in the 1940s, was reported as successful in easing the withdrawal symptoms of 57 out of 70 alcoholics.7 Pyrahexyl was made illegal under UN convention in 1982 despite never having had any recorded instances of abuse or illicit sale.
The synthetic THC compound Nabilone/Cesamet has been available in Canada for decades by doctors prescription. Unfortunately, this THC analogue has proven only moderately effective due to the lack of complimentary cannabinoids such as CBD. The psychoactive effects of cannabis are concentrated in THC, and without the natural buffer of CBD competing for your CB1 receptors, the Cesamet website warns that the “Mental side effects could last for 2 or 3 days.”8 This pharmaceutical flaw leaves room for improvements that are being filled by plant derived products with a more complete range of cannabinoid compounds.
Recently in California, C-3 Patients Association have released “a patent pending advancement in standardizing and administering natural cannabinoids in a pill.” On their website, C-3 refer to Idrasil as “Nature’s ‘Tree of Life’,” in reference to the central world tree of Norse mythology Yggdrasil. Although it is only available to California citizens, C-3 states that Idrasil “will diminish their pain, aid their sleep and enhance their quality of life as a holistic alternative to addictive opiates and life threatening narcotics.”9
Idrasil is an all-natural cannabis plant extract containing the full spectrum of naturally occurring cannabinoids (phytocannabinoids), with a 1:1:1 ratio of CBD, CBN and THC.10 Idrasil is a tablet containing 25 mg of cannabis extract, offering a “consistent, standardized, aseptically processed, bacteria free, non addictive alternative to smoking cannabis.”11
For the many Canadians in need of cannabis medicine who seek to relieve their suffering with an extract, compassion clubs/cannabis dispensaries have diligently pioneered these essential alternatives. However, as previously mentioned, since the judge’s ruling on Apr. 13, 2012, persons authorized under the MMAR may now legally produce their own. Extraction techniques allow for the utilization of previously wasted materials like leaf and stalk, increasing the overall medicinal yield of the plant.
There are two ancient approaches to extracting the resins from the plant body: sifting and rubbing. Dry sifting for “kief” or “pollen” is an ancient technique involving the use of a screen or sieve upon which the raw material is worked or threshed to shake loose the trichome heads. While agitating your plant material over a screen with holes of a certain size, (typically in the range of 25-200 microns) the trichome heads and the medicinal resins they encapsulate fall through, while much of the plant material remains on top. Drier plant material will tend to make greener hash since more of the plant will powderize and fall through with the trichomes. Using fresh material reduces the greening effect and freezing will make the resin brittle and easier to separate.
The sifting process may be repeated to obtain multiple grades of purity. After separating much of the resin from the plant material through a wider screen (100-200 micron), then use a smaller width mesh until the required level of purity is obtained. The purest dry sift has a consistency much like taffy: it can be opaque or translucent and should be very sticky and malleable with a noticeable snap when cold. When exposed to heat, it will begin to bubble and release its vapours. Modern takes on the dry sift method involve more advanced ways to agitate the material (e.g. vibratory sieves, ultrasonics, and precise matching of resin head size to sieve hole size) as well as the use of dry ice. Modern innovation has also provided a variety of small devices that have mastered this task, available for a few hundred dollars.12
Another ancient take on the sieving method is to introduce water and/or ice to the process. This is the idea behind modern “bubble bags” and water extraction. The water serves to carry the resin heads downwards in a cascade through meshes of various sizes as the bags are drained. This idea can be traced back to ancient China and Afghanistan where water washes were performed once the resin had been roughly separated from the ripe plant material in order to purify it further. The drawbacks to water aided sifting are that some of the terpenes (aromatic oils) produced by the trichome are water soluble and will be washed away, as well as the fact that once you get your resin wet, it must be dried properly or risk moulding.
While keeping the maximum amount of surface area exposed is helpful for drying, it can cause your resin glands to degenerate. The THC in the resin will begin transforming into CBN while exposed to air, heat, or sunlight, offering fewer medical properties. The more it is exposed, the faster it will degrade. In ancient times it was common practice to press the dried resin with the aid of pressure and mild heat to create an impermeable skin around the ball of hash. To preserve sifted hash in an unpressed powder form, it should be kept in a hermetically sealed container stored in a cool, dark, and dry place.
Probably the oldest extraction method is hand-rubbed friction extraction, involving the manual removal of the resin from living cannabis plants. It is quite likely that this method predates the use of screens, since one of the first things one realizes when approaching this beautiful plant is just how sticky it is. To harvest in this manner people need simply approach a plant in late flower and rub their hands (or other parts) over the floral clusters. This friction bursts the trichomes, releasing the encapsulated resin, which will stick to skin or gloves. The process is repeated until you have sufficient resin caked up that can then be worked and pressed into shapes. Scissor and finger hash is an incidental form of this type of concentrate that occurs during the trimming stage of harvest. This form of hash is often a black malleable tar, that offers a notable aroma and potency perhaps owing to the lack of degradation of the resin.
Potency, flavor, aroma, and color of the extract vary widely depending on the time of hand rubbing relative to the lifespan of the plant. A skilled hand-rubbing hash maker can draw the resins from a living plant without damaging it several times throughout the growing season. Traditionally, this method comes from areas where there is a large amount of the plant being cultivated. This is the main method of resin collection in Nepal, where the cannabis plant has long been revered. Interestingly, this gentle practice fits the concept of respecting sentient beings that is inherent in the practice of Tibetan Buddhism. There is also evidence of this simple method in Malawi, Africa, and other tropical regions.
Modern technology and scientific understanding has allowed cannabis connoisseurs to put to use various solvents that melt the medicinal magic off the plant. Solvents are generally divided into two basic categories, non-polar (ex. butane, propane, ether, olive oil) and polar (ex. ethanol, isopropanol, acetone). In simple terms, a non-polar solvent is what you want to use to pull the oils off the plant. This is what is widely used to extract oils in the food and health industry. Polar solvents, on the other hand, will extract some of the carbon-based molecules, water, and other ionic compounds from the plant, resulting in a wider spectrum of extractives from the material (including chlorophyll, cellulose, and waxes). Non-polar solvents also dissolve wax well, which composes thecasing of the trichome that surrounds the resin. Care must be taken when choosing a solvent. For butane extraction, at least 3x filtered Butane (with no additives/mercaptans) is needed.
The idea behind solvent extraction is to create a inter-molecular bond with the resins in the plant. This can be achieved by washing the raw material with the solvent, filtering it, discarding the plant bulk, and then evaporating/purging (via heat and/or pressure differential) the solvent to leave behind a film in your receptacle (called a concrete resin) which can then be collected. This works because the solvents are much more volatile and evaporate faster than the resin. An important note for safety: gases from the evaporating solvents are highly flammable and can result in lethal explosions. Always work outside and far away from any sources of ignition/spark. Maintain good airflow at all times and do not inhale the evaporating solvents.
The details and variety of solvent extractions are too vast to unveil in this article, and for many patients the process may be beyond the limits of their physical condition and living environment. The Vancouver Dispensary Society offers a unique (creamy, fluffy looking) form of solvent extract called “Budder.” Dr. Paul Hornby ran tests on Budder that peaked in the 99 percent cannabinoid range with no “toxins, solvents, molds, diseases, heavy metals and other contaminants.”13 The technique for making Budder is kept secret and its price (90/gram) makes it inaccessible to some. As well, due to its fluffy texture, more of the cannabinoids are exposed to oxidation making it degrade faster than a solid form extract.
The absence of contaminants in Budder is probably because BudderKing will “only make Budder from kif, hash, or high-crystal organic buds.”14 During my trial in Feb., expert witness Dr. Pate informed the court that cannabis trichome heads, while containing all the cannabinoids available, are free of all contaminants (except the wax shell), which remain stored within the plants cells. By separating the resin compounds, prior to infusion into a product, the potential for compounds other than cannabinoids is greatly reduced, making doses more precise and consistent.
This particular detail is not included in most of the processing information available today. Rick Simpson Oil uses the whole plant15 as well as Herb the Herbalist in his Solvent Free Oil.16 Dr. Courtney of Cannabis International, while realizing an exciting new direction in cannabis therapy in his raw cannabis juicing video,17 faces this problem also. For these pioneering cannasseurs, it’s even more important that their plants are skillfully grown in prime conditions, and even laboratory tested to ensure purity. Unfortunately, testing facilities are yet to emerge in Canada due to the dubious legal status of medical cannabis.
For most people, access to cannabis in any form to relieve their suffering is sufficient, with the risk of contamination a secondary concern. However, the medical cannabis community includes many vulnerable individuals whose health may suffer from the slightest contamination. This heightened degree of attention may seem extraneous considering the constant threat of criminal charges and the overwhelming demand for cannabis medicines, however, it’s undoubtedly the direction for medical cannabis to move until we, like some ancient cannabis cultures, make this purity the norm.
While patients and dispensaries seek these sensible goals, an unhelpful Health Canada program continues to ignore/vilify extractions, ostensibly tying their authorized users to the fictitious limits of dried cannabis and the potential hazards (heavy metals, moulds, fertilizer) of consuming the plant raw. In their recent “Proposed Improvements to the MMAR,” Health Canada reports that cannabis dispensaries and program participants are the only parties interested in “other forms of products, most notably edibles and extracts.”18
While Health Canada struggles to maintain the rigid terms of the government’s program, individuals with life threatening conditions are immediately in need of the improvements in quality and safety offered by the simple methods outlined above. Following on the heels of states like Colorado and California, major advancements continue to break open the potential of the medical cannabis movement. In the not so distant future, when licensed, taxed, and regulated dispensaries perform their service unhindered and fully equipped, there will likely be a revolution in medical cannabis products that will carry patients safely beyond the current shortfalls of our prohibited industry.
1. Marihuana for Medical Purposes – Statistics (January 8, 2010). Health Canada Website, http://www.hc-sc.gc.ca/dhp-mps/marihuana/stat/_2010/jan-eng.php2 CDSA Schedule
2. Department of Justice Website http://laws-lois.justice.gc.ca/eng/acts/C-38.8/page-24.html#h-27
3. Adams R, Harfenist M, Loewe S. New Analogs of Tetrahydrocannabinol. XIX. Journal of the American Chemical Society. 1949; 71(5):1624-1628.
4. Wilkison, DM; Pontzer, N; Hosko, MJ (1982). “Slowing of cortical somatosensory evoked activity by delta 9-tetrahydrocannabinol and dimethylheptylpyran in alpha-chloralose-anesthetized cats”. Neuropharmacology 21 (7): 705–9 https://www.ncbi.nlm.nih.gov/pubmed/6289158
5. Possible Long-Term Health Effects of Short-Term Exposure To Chemical Agents, Volume 2: Cholinesterase Reactivators, Psychochemicals and Irritants and Vesicants (1984) Commission on Life Sciences. The National Academies Press. pp79-99.
7. Thompson, L. J. and Proctor, R. C.: “The Use of Pyrahexyl in the Treatment of Alcoholic and Drug Withdrawal Conditions,” North Carolina Medical Journal, 14 (October, 1953).
8. Cesamet Important Risk Information http://www.cesamet.com/patient-home.asp
9. C3 Patients Association, Our Mission. http://c3patientsassociation.com/?page=mission
10. European Medical Marijuana product Sativex is challenged by North America’s New Cannabis Pill Idrasil, Says Doobons http://www.sfgate.com/cgi-bin/article.cgi?f=/g/a/2012/05/19/prweb9525356.DTL#ixzz1viWuk9It
13. Pete Brady. Beautiful budder. January 19, 2005 http://cannabisculture.com/articles/3589.html
17. LEAF [The Health Benefits of Juicing Raw Cannabis] www.youtube.com/watch?v=qa0nLdVJiIg
18. Medical Marihuana Regulatory Reform 2011 Consultations Results. Dried Marihuana only http://www.hc-sc.gc.ca/dhp-mps/consultation/marihuana/_2011/program/consult_reform-eng.ph