Making cannabis oil produces a highly concentrated extract from dried herbal cannabis flowers. The cannabinoids are decarboxylated during drying and heating, which is basically a chemical reaction that releases carbon dioxide molecules from the plant material.
This reaction takes place when carboxylic acids lose a carbon atom from a carbon chain. The cannabis oil is then extracted from the plant using solvents.
A solvent is usually a liquid but can also be a solid or a gas, in the case of cannabis oil extraction resinoids can be obtained by extraction with super critical carbon dioxide but this process requires sophisticated and expensive laboratory equipment.
After filtering the solution through filter papers (unbleached coffee filter papers are fine) and then evaporating the solvent, a thick viscous oil remains in the glassware, this remaining oil contains the cannabinoids from the plant. Tetrahydrocannabinoll (THC) and cannabidiol (CBD) are the main focus from a medical perspective.
However, there are currently over 110 different cannabinoids that have been identified in the cannabis plant and it is highly likely more will be discovered as research continues.
Depending on the genetics of the particular cannabis strain the resinous trichomes contained within the female flowers will predominantly produce THC and CBD, in variable amounts.
Certain strains have a genetic predisposition to be higher in THC than others. Regardless of the percentages of THC and CBD contained within any particular strain minor cannabinoids will also be prevalent and this diverse cocktail will be reflected in the resultant extraction when making cannabis oil.
It follows that a cannabis plant strain bred to contain significantly higher amounts of CBD will produce a cannabis oil that mirrors the cannabinoid profile of the plant used for extraction. Correctly manufactured cannabis oils can have THC concentrations as high as 90% and wax products as high as 99% but the cannabinoid content of cannabis oil varies tremendously, since manufacturers use a varying assortment of plants, solvents and preparation techniques.
Unscrupulous dealers have been known to cut or mix cannabis oils with other oils to increase profits so it is important to ascertain whether any oils acquired for medical use have been correctly tested in a reputable laboratory.
THC was first discovered in 1964 at the Weizmann Institute of Science in Rehovot, Israel, by Dr. Raphael Mechoulam and his colleagues.
THC is classified as having high psychoactivity and creates a euphoric effect on the user and certain strains, particularly those of the genus cannabis sativa (C.sativa) produce significantly higher amounts of this cannabinoid when compared to cannabis indica (C.indica) strains.
CBD is also a major phytocannabinoid and is considered to have a wide scope of potential for medical applications due to the lack of side effects, particularly a lack of psychoactivity.
Medical cannabis strains have now been selectively bred to contain significantly higher quantities of CBD and research suggests that those strains that exhibit a 1:1 (THC/CBD) cannabinoid profile are preferable for making medical grade cannabis oil, particularly with regard to cancer treatment.
The endocannabinoid system (ECS) is a group of endogenous cannabinoid receptors located in the brains of all mammals, cannabinoid binding sites also exist throughout the central and peripheral nervous systems, consisting of neuromodulatory lipids and receptors.
Basically The ECS is the body’s own cannabinoid system and is involved in a variety of physiological processes including appetite, pain sensation and management, mood, memory, immune system functions and also in mediating the psychoactive effects of cannabis.
It makes sense that if the body has its own cannabinoid system that the addition of further cannabinoids will in effect bind to and further enhance the cannabinoids already naturally produced.
This is of significance when creating cannabis oils for medical use. Cannabinoids are a complex fusion of natural chemicals that have evolved over time within the cannabis plant which is effectively an organic chemical factory.
When making cannabis oil it is important to remember that cannabinoids work in synergy with each other and whilst increasing the availability of CBD in some strains gives a wider spectrum of choice for cannabis oil makers, research shows that it is counter productive to isolate any particular cannabinoid.
Research has shown, particularly in cancer patients, that they benefit from the full and complex profile of cannabinoids far better than treatment with isolated cannabinoids.
This has shown to be the case with regard to GW Pharmaceuticals trials on Sativex which is a mucosal spray comprising of only THC and CBD extracted from the cannabis plant.
It failed to have any benefit for cancer patients during exhaustive trialing and cannabis oil makers who have claimed success with cancer patients are adamant that research will prove the efficacy of using the complete spectrum of cannabinoids as nature intended, rather than extracting and isolating any specific cannabinoids.
CBD in isolation is now marketed as a potential breakthrough in the fight against cancers, however this has not been proven by any clinical trials and has more to do with the fact that it can be legally sold whilst cannabis is still subject to irresponsible prohibition laws.
CBD in isolation has a limited medicinal value and really needs to be administered alongside the whole spectrum of other cannabinoids to be effective.
Understanding the differing effects of THC and CBD allows cannabis oil makers to better decide on the strains to be used in the extraction process.
Cannabis oil with higher THC content is preferable when treating conditions such as Chron’s disease, depression and psychological disorders such as PTSD, whereas cannabis oils that are produced with higher quantities of CBD are recommended for cancer patients and treatments where a less psychoactive response is preferable.
A wide variety of solvents can be used for extraction when making cannabis oil and can be broadly classified into two categories: polar and non-polar. Non-polar solvents such as benzene, chloroform and petroleum ether will not extract the water-soluble constituents of marijuana or hashish, and will yield a more potent oil as a result.
Polar solvents such as alcohol will extract undesirable water soluble substances such as chlorophyll’s and sugars.
An important property of solvents is their boiling point. This determines the speed of evaporation when completing the final stage of making cannabis oil.
- Low boiling point – below 100 °C (boiling point of water)
- Medium boiling point – between 100 °C and 150 °C
- High boiling point – above 150 °C
Some of low boiling point solvents such as acetone will evaporate at room temperature, whilst high boiling point solvents need higher temperatures, or the application of a vacuum for faster evaporation.
Here is a brief guide to the differing extraction methods but all follow the basic format of oil making that requires you to extract the cannabinoids from your chosen strain using solvents.
BHO: Butane Honey Oil
This is a cannabis oil extracted using butane gas. Butane has a low boiling point of 0.5 °C (31.1 °F) and using butane is very dangerous and it must always be performed outdoors.
There have been many instances of fires caused by people using butane as an extraction solvent and some fire departments in the U.S. have gone so far as to issue warnings against its use.
There are many companies who sell ready made Butane gas extraction kits and they are readily available online.
The best advice we can give is to not attempt this extraction process, if you decide to do so then wear protective clothing and always carry out the procedure outdoors away from any flame source.
These injuries were sustained attempting to make Butane extracted cannabis oil.
The individuals cotton sports pants caught fire and injuries to the legs and groin area were extensive with serious burns to the penis and testicles, his hair caught fire and he sustained severe burns to the scalp and face resulting in noticeable scarring.
Butane is a highly volatile gas and should never be used to extract cannabis oil for medical use, it is far too dangerous.
This refers to Quick Wash Isopropyl, which literally means a ‘quick wash’ in Isopropyl alcohol, the cannabis is typically in the alcohol for under a minute, this method can produce a very high quality oil.
Full Extract Cannabis Oil, differs from QWISO as the cannabis has more of a soak than a wash, FECO fans often use Everclear® a 190- proof Grain Alcohol. It produces a very good quality oil.
Everclear grain alcohol, is the brand name of a colorless, unflavored, distilled beverage sold in some states in the U.S. and bottled at two different high strengths: 151-proof and 190-proof, meaning respectively 75.5% and 95% alcohol by volume,
190-proof spirits are the strongest that are available and they are ideal for this basic method of making cannabis oil. It is illegal to sell 190-proof Everclear in California, Florida, Hawaii, Iowa, Maine, Massachusetts, Minnesota, Nevada, New Hampshire, North Carolina and Virginia. It can be purchased in Ohio but only under severe restrictions. In Canada, Everclear is sold in the province of Alberta but not in other provinces.
In British Columbia, it is available for purchase only with a permit for medical, research, or industrial use. Everclear is difficult to obtain in the E.U, it is however possible to distill your own solvent.
Hemp Seed Oil
This is usually referred to as ‘Cold pressed hemp oil’ and is made by pressing non psychoactive cannabis hemp seeds, the extracted oil is very healthy and nutritious but it is not suitable for curing medical conditions as the seeds do not contain cannabinoids.
Cannabis Oil Infusion
Infused oil differs from an extracted oil in that it’s not as concentrated; but hemp oil or olive oil infused with cannabis makes a versatile edible. Infusions are not suitable for treating serious medical conditions.
Rick Simpson Oil
RSO refers to the oil promoted as a cure by cancer sufferer Rick Simpson, who was one of the first to pioneer making cannabis oil. It is made by extracting cannabinoids by the use of a solvent, such oils are high in cannabinoid content. The use of the name ‘Hemp Oil’ to describe this extraction is confusing to say the least (see above).
Solvents Commonly Used in Making Cannabis Oil
Extreme caution must be taken when using solvents. Health hazards include nervous system damage, liver and kidney damage, respiratory damage, cancer, and skin disorders.
Many solvents can lead to a sudden loss of consciousness if inhaled in large amounts. Solvents like chloroform have been used in medicine as anesthetics and sedatives,
Many solvents can have harmful long term health effects so precautions must be taken; always wear protective clothing and gloves. Never work with solvents in an enclosed space without a suitable mask or respirator.
Most organic solvents are highly flammable, depending on their volatility. Mixtures of solvent vapors and air can literally explode.
Solvent vapors are heavier than air; and will sink to the floor and cause a potentially lethal, explosive mixture in an enclosed environment.
Solvent vapors can also be found in supposedly empty drums and cans, posing a flash fire hazard so empty containers of solvents should be stored open and upside down.
Examples of solvents used in making cannabis oil
Chloroform, or trichloromethane. Boiling point: 61.15 °C (Non Polar)
Chloroform is an organic compound. It is a colorless, sweet-smelling, dense liquid that is produced on a large scale as a precursor to PTFE and refrigerants. Chloroform is a dangerous solvent to work with due to its ability to render you unconscious.
Naptha. Boiling point between: 30 °C and 200 °C (Non Polar)
Light naphtha is the fraction boiling between 30 °C and 90 °C and consists of molecules with 5–6 carbon atoms. Heavy naphtha boils between 90 °C and 200 °C and consists of molecules with 6–12 carbon atoms. Naptha is extremely volatile and can explode on exposure to high temperature so great care must be taken when it is used for making cannabis oil. Naptha is recommended by Rick Simpson, however there are concerns expressed by some that Naphtha can be carcinogenic. Some commonly available forms of Naptha contain impurities which may also have harmful properties of their own.
Isopropyl alcohol. Boiling point: 82.6 °C (Polar)
This solvent is miscible in water, ethanol, ether, and chloroform. It will dissolve ethyl cellulose, polyvinyl butyral, many oils, alkaloids, gums and natural resins. This solvent is commonly used in making cannabis oil but will dissolve undesirable compounds such as chlorophyll.
Pentane. Boiling point: 36.1 °C (Non Polar)
Pentanes are often used as specialty solvents in laboratories. Their properties are very similar to those of butanes and hexanes.
Hexanes. Boiling point: 50 – 70 °C (Non Polar)
Hexanes are all colorless liquids at room temperature, odorless when pure. They are widely used as cheap, relatively safe, largely unreactive, and easily evaporated non-polar solvents.
Dichloromethane (DCM, or methylene chloride) Boiling point: 39.6 °C (Non Polar)
This is an organic, colorless, volatile liquid with a moderately sweet aroma is widely used as a solvent. Although it is not miscible with water, it is, however, miscible with many other organic solvents. This solvent has a very low boiling point.
Acetone. Boiling point: 57 °C (Polar)
Easily available as a solvent and degreaser, Acetone evaporates rapidly and it is a popular solvent and is recognized to have low acute and chronic toxicity if ingested and/or inhaled. Acetone has been internationally rated as a GRAS (Generally Recognized as Safe) substance for food use and is produced and disposed of in the human body through normal metabolic processes. The most hazardous property of acetone is its extreme flammability. At temperatures greater than acetone’s flash point of -20 °C (-4 °F), air mixtures of between 2.5% and 12.8% acetone, by volume, may explode or cause a flash fire. Vapors can flow along surfaces to distant ignition sources and flash back.
Petroleum Ether. Boiling point: 35‒60 °C (Non Polar)
This is commonly used as a laboratory solvent. The term ether simply means extreme lightness and volatility. Ether is not commonly used as a solvent in producing cannabis oil.
Ethanol. Boiling point: 78.37 °C (Polar)
Also known as drinking alcohol it is a volatile, flammable, colorless liquid with a slight chemical odor that most will be familiar with. It is also used as an antiseptic, fuel, and due to its low freezing point has many other uses.
Methanol. Boiling point: 64.7 °C (Polar)
This is the simplest alcohol. It is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to that of ethanol (drinking alcohol). However, unlike ethanol, it is highly toxic and unfit for consumption. At room temperature it is classified a polar liquid and widely used as an antifreeze.
Benzene. Boiling point: 80.1 °C (Non Polar)
This term actually refers to a variety of highly flammable liquid hydrocarbon mixtures produced from natural gas condensates, distillates, or the distillation of petroleum, coal tar and peat.
Solvent-less Cannabis Oil
Solvent less techniques strictly speaking do not produce what could be termed making cannabis oil.
They are better classified as extracts as they are generally smoked and really belong in the Medical Extract category, but nevertheless are worth mentioning in this article.
Iced water using bubble bags and dry ice extractions produce hash, but the Rosin technique is a method of extracting a pure cannabis extract without the need for volatile chemicals or the lengthy process that solvent extraction can take.
Using only a cheap hair straightener, some parchment paper, and little or no experience or expertise this technique allows patients access to high purity medicine in a matter of seconds.
The process required to create rosin only allows for a limited amount at a time, however using a t-shirt press or a larger heat press you can increase the load and overall yield.
There is no unwanted plant matter in the final product as the combustion temperature for cannabis is between 500-700 °C and the press does not generate that level of heat. Unlike solvent-extracted oils and waxes, there are no solvents used to separate the cannabinoids from the plant material so there is no danger of solvent residue in the final product.
If you need any advice or help please use the contact form provided. We try to answer all emails within 24 hours and are happy to help and advise on all aspects of medical marijuana treatments in complete confidence.