Extraction
Cannabis concentrates (cannabis oil, butter, wax or shatter) are the cannabinoids of the cannabis plant that have been extracted using one of the many known extraction methods described below. They are significantly more potent than regular hashish or cannabis flowers and their applications as medicine have proven to be diverse and effective; however, the extraction of cannabis concentrates is a complex and potentially dangerous process – the methodology required for proper extraction is precise.
Cannabis extract can be stored and frozen for long periods without degrading normally in dark amber glass bottles to limit light.
Cannabis flower cannot be frozen as the trichomes fall off.
The science of cannabis concentrate extraction functions on the solubility of the cannabinoids and other active ingredients of the cannabis plant. Cannabinoids are not water soluble, so to extract them properly the cannabinoids must be dissolved in a solvent.
Solvents are the chemicals used to remove the cannabinoids from the cannabis plant. Butane, hexane, isopropyl alcohol and ethanol are all solvents that are commonly used in cannabis concentrate extraction. When cannabis flowers are submerged in these solvents, the cannabinoids, terpenes and other active ingredients are dissolved into the liquid or gas solvent. The remaining solid plant matter is filtered out and the liquid solvent and cannabinoid mixture is purged to remove all solvents, leaving only cannabinoids and other active compounds of the cannabis plant.
Incredible scientific precision is required to properly remove all trace solvents from a cannabis concentrate. Any residual solvents can be harmful to patients. Different extraction methods are used to create cannabis concentrates, all with varying degrees of effectiveness.
Dry Sieve
The most naturaly and unobtrusive form of cannabis extraction, often considered the holy grail of concentrates by true connoisseur, due to its low yield and the meticulous process involved in removing the cannabinoid containing trichomes from the plant matter.
There are many grades of dry sieve from “farmer sieve” containing plant contaminant, to what is often times referred to as “kief”, a mixture of glandular trichrome heads, stalks and plant material, up to “Fullmelt Dry Sieve” which generally contains just the trichome heads themselves.
There are multiple ways to achieve dry sieved products, but more often than not a single silk screen or series of silk screens can be utilized in conjunction with agitation to separate trichomes from the plant material creating a smokeable, edible, or vaporizable cannabis concentrate.
Water
Very much like the dry sieve process, water can be used in conjunction with screens as a vessel to carry mechanically separated trichomes through multiple micron level screens. A micron is a microscopic unit of measurement used to calculate the size of the trichrome and thus the holes in the screens themselves. Water hash, also termed “Iceolater”, “Bubblehash”, “Solvent-less”, “Ice Wax” and other names is made using agitation, generally from ice and motion, either done by hand or utilizing a washing machine to gently break off the trichrome heads from the plant material. Water extracted products must be broken down and dried thoroughly before being consumed or there is the be possibility of mold and health risks due to improper storage.
CO2
Arguably the least-toxic form of cannabis concentrate extraction, CO 2 (carbon dioxide) has become more popular as an extraction method because of its low environmental impact and nonexistent toxicity; however, CO 2 extraction systems are considerably more expensive than butane or hexane systems. CO 2 functions as a solvent when it is heated or cooled and pushed through the flower at high (supercritical) or low (subcritial) pressures. In fact, 95% of the cannabis extractions right now are done in the subcritical phase.
Most people tend to prefer subcritical CO 2 extraction because it gives a lighter colored extract, fewer waxes and resins, and retains significantly more volatile oils compared to supercritical CO 2 extraction; however, without the proper equipment rated for the proper pressures, creating quality CO 2 extracted concentrates is incredibly difficult.
Isopropyl Alcohol
Isopropyl alcohol is a commonly used solvent for creating cannabis concentrates using a ‘quick wash’ method. Where hexane is not water soluble, isopropyl alcohol is highly water soluble and will dissolve undesired plant materials (chlorophylls and waxes) along with the sought after cannabinoids. In order to eliminate plant waxes from the isopropyl concentrate solution, a quick wash method is used as opposed to soaking (which is with non-water soluble solvents like hexane). Although the isopropyl method receives great reviews from patients and tasters, it takes significantly longer to properly purge isopropyl alcohol extracted concentrates due to the solubility in water.
Butane & Propane
The most commonly used solvent in cannabis extraction is butane; however, a mixture of butane and propane has recently become very common as well. These solvents are nontoxic, non-polar and they dissolve oils very efficiently without creating other unwanted by products. Butane and propane dissolve all cannabinoids and terpenes (aromatics) with great effectiveness while preserving the integrity of the delicate cannabinoids..
The Hydrocarbon Solvent of choice is Primarily N-Butane. Organically friendly and NON-TOXIC. This solvent has been used in the food industry for decades because it is one of the easiest solvents to cleanly evaporate away, leaving no trace and does not react with the food products being extracted. Butane is a non toxic, very non polar solvent that has a linear molecular which is made up of hydrogen and carbon atoms that allow it to dissolve oils very effectively without reacting and creating other unwanted products. It will dissolve and extract waxes oils and very delicate aromatics with great efficiency while preserving the integrity of the highly evaporative volatile compounds. Once extracted, the extracted components will more closely match the aroma, flavor and taste exactly as they resided in the plant. They will not be lost or destroyed during the extraction and evaporation and or recovery of the solvent used to extract them out because it is all done at very low temperatures and pressures.
Hexane
Like butane, hexane is a solvent that can be used for cannabis concentrate extraction. Some interesting information: hexane is completely insoluble in water, it boils at a higher temperature than butane, and is extremely flammable and potentially explosive. Although the general process for hexane extraction is similar to that of butane extraction, it requires significantly more care due to the fact that hexane is considerably more toxic.
Rosin
The tools needed to make rosin include:
Flat Iron (2+” with temperature control) or other heat/rosin press
Non-stick parchment paper
Collecting device (TI dabber, razor blade, etc.)
Processing material (flower, dry sift, bubble hash)
25u micron screen
Step 1: Prepare your processing material by breaking it down to .2 – .5 increments. Cut 10-20 pieces of parchment paper in 4” x 8” strips. Preheat the flat iron to 200*F – 340*F (the lower the temp, the tastier the end-product). Lower temperatures (250°F- 300°F) = more flavor/terpenes, less yield, end material is more stable (shatter), where as higher temperatures (300°F- 335°F) = less flavor/terpenes, more yield, end material is less stable (sap). Some extraction artists claim the best way to make Rosin is at 302°F (150ºC), with 4-6 seconds of pressure, using just 0.25 gram samples in each run — but this process has not been confirmed by Medical Jane or any other official studies.
Step 2: Take one of the small increments that you prepared and wrap it in the center of the 25u micron screen. Place the screen with the product on a piece of parchment paper and then fold the paper over, leaving the product in the center. Place the parchment paper on the flat iron and apply pressure for 3-5 seconds directly on the product.
Step 3: Remove the pressure from the flat iron and take off the parchment paper, unfold the parchment paper. The starting product will be surrounded by the rosin, remove the product being careful to leave all of the rosin behind. Take your collecting device and scrape the parchment paper to collect all of the finished product.
Sterilisation
Microbiological control is important though out all stages of production but now it extremely important once the flowers have been cured.
Containments and pathogens are every where and are of a very small particle size so they are air bourn. They will only proliferate and flourish if conditions are suitable.
Sterilised cannabis has a longer shelf life.
Since opportunistic infections pose the greatest danger to immune suppressed (patients) sterilisation is necessary.
In contrast to popular belief, the heat released by smoking does not fully protect you against microbes. The spores of many kinds of mould are heat-resistant, and can be inhaled together with the smoke. And once a mould has started growing in cannabis buds, it may produce large quantities of toxic compounds that can also be inhaled. Such a toxin is Aflatoxin they are naturally occurring mycotoxins that are produced by species of fungi, Aflatoxins are toxic and among the most carcinogenic substances known.
Carefully cultivated and harvested cannabis harbours a minimum of hazardous microorganisms. For added protection, material must be screened for contamination before it is packaged and after for use as medical cannabis.
Cannabis needs to be sterilized but only certain techniques can be used due to the fact cannabinoids can be destroyed.
Cannabis should be sterilised, preferably by gamma irradiation.
A key characteristic of Gamma radiation is the high penetration capability. This enables moderately dense or sealed products to be processed with relative ease and facilitates treatment of palletised product. The unit of absorbed dose is kiloGray, expressed as kGy. The absorbed dose is determined by product density, pack size, dose rate, exposure time and to some degree by plant design. The dose delivered is measured by a dosimetry system. A typical dosimetry system involves the use of perspex to measure a colorimetric change caused by the dose. The radioisotope cobalt 60 is the energy source for use in Gamma irradiation plants and is manufactured specifically for this purpose. The irradiation process takes place in a specially designed cell.
. Lastly, consumers must be given careful instructions to ensure their cannabis does not become contaminated prior to use.
Each individual batch of cannabis produced must be tested for the following aspects:
General appearance – flower buds must have certain size and appearance. No contamination with dust, hair, insects, burn marks etc.
Water content - should be less than 10% - 15%
Potency – content of THC, CBD and CBN along side the other compounds must be between specified levels.
The active substances must be the same in each individual harvest ensuring that the strength of the product supplied is always the same.
Microbiology – bacteria and molds must be well below safety limits.
Pesticides , herbicides or fungicides - must be absent.
Heavy metals and other contaminates – must be well below safety limits.
Cannabinoid Testing
The 3 major testing methods are GC, HPLC and HPTLC all these are similar – all involve running a sample through treated silica to separate the different cannabinoids from one another, and then measuring the amounts of the different cannabinoids – but the details of how this is done makes the different technologies best suited for different applications.
GC is perhaps the most common method of chemical analysis in use in the world today. In GC, the sample under study is vaporized and then pushed by a mix of gases through a long, thin, coated tube, not unlike a hollow fiber optic line up to 60 feet long. The different cannabinoids separate from each other as they travel, and are measured at the far end, usually by a detector known as a FID that burns whatever comes out of the tube and looks for the products of combustion. (One alternative detector is a mass spectrometer, much more sensitive but far more expensive and difficult to operate.) The response from the detector is compared to the response to a “reference sample” that contains a known amount of specific cannabinoids in it. Comparing the timing and size of the signals from the detector allows the analyst to calculate the amount of targeted cannabinoids in the unknown sample.
GC is terrific for measuring small quantities of cannabinoids. For cannabinoid testing, its main weakness is that, because the sample is vaporized at high temperatures when it enters the machine, it cannot distinguish THC from THC-A in a sample unless significant additional processing is done. This makes the technology impractical for testing infused products. The coated tubes cost several hundred dollars apiece and are used for hundreds or thousands of tests before replacement, leading to problems from contamination and degradation of the column.
HPLC, the sample is pushed by liquid solvents through a short tube packed with silica particles. The separated cannabinoids are measured at the far end, usually by monitoring the output with a beam of ultraviolet light. The main drawback of this method is that the UV detector responds to many substances in addition to cannabinoids, leading to interference, and has significantly different responses to different cannabinoids, requiring calibration for each separate cannabinoid. As with GC, the columns must be re-used many times, leading to contamination and degradation problems. Finally, HPLC equipment tends to be temperamental, with significant downtime for repair and maintenance.
HPTLC, the sample is “spotted” onto a disposable, silica-coated plate. Liquid solvents are then run across the plate, separating out the cannabinoids. The plates are treated with chemicals and scanned at a particular frequency to reveal the cannabinoids. HPTLC particularly lends itself to the analysis of complex mixtures, such as plant or food samples, as detection can be limited to specific groups of substances – in this case, cannabinoids – and the use of disposable plates means that no residues accumulate from one test to the next. The main limitation of HPTLC is that it is not as sensitive to minute levels of cannabinoids as GC or HPLC. However, even the most dilute medical cannabis products such as sodas and drinks contain enough cannabinoids to be accurately measured with HPTLC.
Decarboxylation
Cannabis produces THCA, an acid with the carboxylic group (COOH) attached. In its acid form, THC is not very active. It is only when the carboxyl group is removed that THC becomes psychoactive. THC exists within the cannabis plant in a form that has a CO2 attached to it. This is considered to be an inactive form. When that molecule is heated, the CO2 easily pops off and floats away. This is then the "active" form of THC. How much heat is required to break off this CO2. The warmer it is the faster it floats off.
At room temperature the CO2 will all be gone in about a year.
At 200F it should all be gone in about a half hour.
At 300F it should be gone in about 2 seconds.
In a burning ember (say 2000F) instantly.
At body temperature (as in oral) it takes several hours.
When cannabis is smoked, the THC behind the hot spot is vaporized as the hot air from the burn is drawn through the joint or pipe bowl to the unburned material. The liquid THC and other cannabinoids have a boiling point of between 180-200 C (355-392 F). Before they turn gaseous the carboxyl group is released from the molecule as carbon dioxide and water vapour.
CBD also exists within the plant in the form of CBDA. It also, when heated, tosses off a CO2 to become CBD.
Many of the other cannabinoids within the cannabis plant exist in the inactive, acid form.
Now then a note of caution about the application of heat. Some of the most beneficial compounds within the plant are those that make up the smell and colours of the plant. Many of these drift off when you warm the material.
There is a balance between enough heat to activate it and the loss of potential medically valuable compounds.
When cannabis is heated to convert the THCA and CBDA into THC and CBD, we are also converting THC to CBN at a faster rate. At about 70% decarboxylation, we actually start converting THC to CBN at a faster rate than we are converting THCA to THC, so after about 70% decarboxylation, the levels of THC fall sharply.
The goal of cannabis decarbing is to activate the cannabinoids with minimal vaporization of cannabinoids or terpenes (cannabinoids responsible for how cannabis smells). The lower the temperature, the longer the decarb time required, but less loss of terpenes due to vaporization. Heating cannabis in a closed container will help reduce the loss of cannabinoids and terpenes by trapping any vapor and allowing it to be reabsorbed into the cannabis material as it slowly cools down after being decarbed.
Using dry material placed in an oven at any given temperature is very difficult to have uniform temperature throughout instantly upon placing it in a heated oven, nor know for sure the state of. Decarboxylation
Decarboxylating plant material will alter the taste of product it will become (roasted/toasted) .
Decarboxylating extract (oil) it is very easy and It is simple to monitor the state of cannabis oil decarboxylation placed in a 121C/250F hot oil bath, because you can watch the CO2 bubble production.
CO2 bubble production will proceed at its own observable rate. you can tell exactly when the bubble formation suddenly tapers off.