Extracting Pristine Cannabis Terpenes
14/05/2020 | By George Stantchev, Ph.D.
Why is it important to preserve native terpene profiles?
Terpenes are volatile aromatic molecules that evaporate easily and readily announce themselves to the nose. Various researchers have emphasized the pharmacological importance of terpenes, or terpenoids, which form the basis of aromatherapy, a popular holistic healing modality. Cannabis compelling fragrance and particular psychoactive flavor are determined by the predominant terpenes in a strain.
There are over 3000 terpenes in nature and 400 of them have been found in the cannabis plants where 70 of them are identified as cannabinoids, but only a few of these odiferous oily substances appear in amounts substantial enough to be nose worthy. Among them are monoterpenes, diterpenes, and sesquiterpenes, which are characterized by the number of repeating units of a 5-carbon molecule called isoprene, the structural hallmark of all terpenoid compounds.
The terpenes in marijuana have given the plant an enduring, evolutionary advantage. The terpenes are the natural hormones of the plant. During the vegetation of the plant the terpenes change from repelling insects and animal grazers, preventing fungus to attracting pollinators and male plant pollination. In a similar manner the terpenes also known as essential oils elevate human emotions and very often are causing subliminal effects. That is why essential oils are a base of most perfumes and aromatherapy concepts. In many cases nature is our best formulator talking about the effect of various plants and cannabis strains to human health. That is why finding a process preserving natural strain specific extracts without degrading or creating byproducts is our main target.
Out of the 70 known cannabinoids that occur in the cannabis plant. Each of them have specific functions in stimulating certain cells. As example CBD stimulates collagen, CBG stimulates the stem cells, THCV stimulates the peripheral nervous system, THC stimulates the central nervous system, etc. Collectively the effect of all cannabinoids, terpenoids, and flavonoids define the so-called entourage effect of the plant. Why entourage effect is so important because the terpenes by itself modulate the effect of the cannabinoids and amplify it by itself in time. So a proper combination of cannabinoid with a terpene can amplify, prolong or speed up the medical effects of the plant.
How much loss is typically seen with standard terpene extraction protocols?
Тhe main terpene extraction process used for centuries is steam distillation. Since the steam does not dilute the terpenes but helps them to evaporate and condensate the extraction of terpenes with steam is a side effect, i.e. the practical yield is very low but it is compensated by the cost and simplicity of the extraction. For example, to extract 1kg rose oil by steam is needed for a 3,000kg fresh flower and if solvent extraction is used it is around 500kg to produce 1kg extract. Therefore the solvent extraction can increase the yield about 6 times. That same statistic can be traced among many aromatic herms as lavender, mint, sage, etc. It is usual that the amount of terpenes in the aromatic plants is around 0.1 to 0.5%. That is typical for the wild cannabis sativa as well. In well cultivated sativa the terpenes can be increased a few times well up to 2.5% and in indica up to 5% in the cultivated varieties.
How do we compare to other processes, like subcritical CO2, steam distillation, etc.?
Other solvent extractions sometimes used in terpene extraction are as example hexane, CO2 and hydrocarbons. In a retrospective the 90% of the extraction of terpenes, i.e. essential oils is done in the fresh flower stage where the terpenes are still in full boquete, unaffected by other factors during drying as time, sunlight and heat. The lowest cost solvent extraction on fresh flowers is by use of hexane or or similar water insoluble solvents at ambient pressure as pentane, heptane, etc.
The hexane extraction lasts for about an hour with agitation and the solvent is drained and removed in a rectification tower. The solvent evaporation is at around 68 degree C and since most of the terpenes are preserved in this initial stage the extract is very thick and known as concrete (a form of crude). Since the hexane crude extract is rich on lipids and fats further refinement is necessary with a lipophilic solvent as ethanol. After a dilution, freezing at around -40 degree C for around 48 hours, winterization or filtration of the extract is needed to isolate the essential oil.
After the winterization the ethanol should be evaporated as well and since the ethanol boiling point is around 78 degrees C and the first terpene evaporation point is at around 105 degree C there is a substantial loss of the most volatile terpenes. They escape together with the evaporated ethanol which also contaminates the ethanol and further solvent refinement is needed. On another hand the use of hexane is not intended for a food grade product. The hexane extraction is mostly used in the fragrance and pharma fields where the hexane residues affecting the taste are not considered critical. In the US some of the cheap CBD isolates are produced that way.
The use of CO2 in extraction of terpenes has been limited only to when dry flowers are extracted. Extracting fresh flowers with high water content is a challenge for the CO2 process since the aggressive CO2 solvent when its liquid state reacts with the water components and converts to an acid. The minimum condition to put the CO2 in a liquid state in order to extract at reasonable temperature is over 70 atmospheres of pressure. It is the same atmospheric condition as on the planet Venus where the CO2 is residing in its liquid form.
In the diagram below a range of organic substances are shown and bars of the solubility of various solvents. Understanding the solvent is of major importance for extraction of the full spectrum resin. There are oil soluble compounds, alcohol soluble compounds and water soluble compounds in the plants, that is why it is important to select your solvent base in regards to what compound to be extracted.
The first issue with CO2 when we look at the diagram below is the fact that in supercritical mode terpenes are not extracted. Therefore the extraction of terpenes will need to be done in subcritical mode. In that mode the cannabinoids are not extracted. Also in sub-critical mode the CO2 is a very low dense solvent that requires time and proper pressure to be effective. In order to achieve a reasonable yield for terpenes in subcritical mode an extraction can continue for 5 hours. As an example using hydrocarbons that process takes only 15 minutes. That is why CO2 is not too popular in the fragrance and flavor industry which are the leading industries in terpene extractions.
We see a similar problem with ethanol were the major terpene classes are not extracted due the polar nature and high boiling evaporation temperature preventing good separation. Not to forget that both solvents CO2 and ethanol are aggressive polar solvents and they oxidize some of the components while creating byproducts. That is why an extraction of volatile compounds like terpenes is essential to be extracted in very inert environments without resident oxygen or air flow and at normal temperatures that do not convert or degrade those compounds.
What are the safety aspects of fluorocarbon?
As it was discussed earlier there's a big problem today in the cannabis extraction industry. There are many variants of oil soluble compounds with medicinal values in the cannabis plant and due their consistency they cannot be extracted together. Thick oils as the cannabinoids are extracted one way and the volatile oils another. Every one of the major extraction methods has a core flaw in their process, whether its high pressure, high temperature, dangerous, toxic solvents or solvents that creates byproducts, anyone or combination of these is very destructive to the plant profile and the usual extract received is called "crude oil" with a lot of unwanted components inside which requires extensive post processing.
PURE5 uses a low pressure and room temperature extraction which extracts the terpenes and the cannabinoids in the plant without extracting all the unwanted components (fats, lipids, waxes or chlorophyll). The solvent used is R-134a which is a fluorinated hydrocarbon also known as Freon. In the past Freons were used in cleaning, coolin, heathing, aerosols, additives to breathing mixtures, purification, etc from multiple industries. There are also freons like R11 and R22 that are outdated due the negative effect on the ozone layer. Although the R134a was a saver and vetter replacement that does not cause the ozone layer depletion. It is recognized as GRAS by the FDA and widely used in aerosols as an agent for oral drug delivery.
Compared to hydrocarbon and isobutane, R134a is human and operation safe, non toxic, non flammable with no ozone depletion potential. It is a nonpolar solvent, similar to hexane and butane without the high combustion danger they possess and it extracts very fast the oil soluble fractions, i.e. the terpenes and resins. Due to its inert and water insoluble characteristics it can extract easily fresh products with large water content. The small molecule size penetrates the plant tissue easily and maintains the PH level throughout the process and is delivering the undamaged terpene and cannabinoid profile in oil. That makes it very well suited for pharma applications as well. Since the boiling point is at -30 degree C it can be easily separated from the extract so the extract can be free of residues.
The small non polar molecule size and the inert nature of the TFE solvent penetrates the plant tissue well and extracts thoroughly the oil soluble fractions. We extraction is performed at room temperature conditions and the extraction process is seamless to the full spectrum resin delivered from the plant. Full terpene profile is collected without degradation of components and it is easily separated from solvent. That is why the extraction is very often done on fresh plants as well, therefore it has been used widely instead of hexane in the food industry. The extraction of terpenes is fast and clean of byproducts, as example if CO2 in subcritical mode needs 5h to extract limited terpenes, the R134a needs only 15 min for full terpene profile extraction.
What is PBX Process?
PURE5TM Extraction is introducing a line of Pure Botanical Extracts (PBXTM) hemp terpenes extracted from fresh flowers such that the terpene profile native to the original cultivar is preserved. The terpenes are captured using a non-destructive botanical extraction process that concentrates them in an unaltered profile, and suspends them in other natural oils from the plants.
The highest quality hemp or cannabis flowers are selected and subsequently coupled with the Pure Botanical Extraction (PBX) process to deliver the highest terpene concentrations. The process can be custom tuned to extract only terpenes and suppress some of the cannabinoids as example THC. The cultivars are uniquely grown to boost the full terpene spectrum in the flower, then selectively extracted to isolate major and minor terpenes native to the flowers. The extraction process employs a low-pressure, room-temperature, non-polar fluorocarbon solvent allowing us to capture every potential terpene along with elements and ketones.
Myrcene, caryophyllene, humulene, pinene, and linalool are more common amongst hemp flowers, however, the quantity present in Lifter makes this a very complex flower profile yielding superior entourage effects. Lifter is just that… it will lift you up! The plant profile reveals terpenes present such as trans-ocimene (mint, parsley, basil, and mango), terpinolene (pine, nutmeg, and lilacs), and limonene (citrus, fruits, and juniper) which stand out amongst the typical hemp plant terpene profiles.
Original Lifter Flower Terpene Profile
Lifter Extracted Life Resin with preserved Terpene Profile
Lifter Extracted Full Spectrum Oil with preserved Terpene profile
The flower can be extracted for terpenes or for full spectrum oil. In one case the terpenes are over 5% and the other over 33%. The life resin extracted terpene profile repeats the exact flower terpene profile in approximately 30 times more concentrated form and the one in the full spectrum oil 4 times. The additional two terpenes detected in the extract were below the detection threshold in the flower and were detected in the extract after being concentrated. Since the extraction is carried out at room temperature there is no destruction of existing terpenes or new by-products created in the process. We further isolate the terpene to over 60% concentration and in that case the extract is 100 times more concentrated than the original plant.
PBX terpene oils can be added to all hemp-derived products as example distillate, isolate or crude extracted with other means that lack the original terpene profile and enhance flavor and ensemble effects. Our terpene extract is supplied with a chain of custody back to the original cultivar. Additionally, our products are third-party tested for cannabinoids, terpenes, residual solvents, inhalable microbial contamination, and pesticides.
Most botanically sourced terpenes are extremely concentrated, however, they’re often suspended in alcohol. These solvents are, therefore, in your formulations regardless of what’s present. PBX delivers all the components of the flower we want and none of the by-products that the widely used elsewhere solvents CO2 or ethanol will create due their aggressive nature. As explained above due the aggressive nature of some polar solvents during extraction and access to oxygen they oxidize some of the constituents. That oxidation limits the antioxidant activities on the extracts produced which lowers their medicinal value and increases the PH. The high medicinal value of a botanical product is directly related to their ability to inhibit the free radicals in the body which relates to their natural antioxidant activity.
In addition all cold ethanol extracts that are not processed with proper winterization are still rich in waxes and long sugar lipids that limit the ability of the terpenes to absorb and release potent aromas.
Who we are?
At PURE5 Extraction (powered by COMERG), we design and manufacture cost- and process-optimized extraction systems and applicable post-processing stages targeting specific end products. COMERG is committed to offering the fastest, safest, and most economical extraction process for Cannabis sativa oils named Pure Botanical Extraction (PBXTM) standard.
Our technology originated from building machines for fragrance and flavor production in Europe utilizing various solvents as hexane, steam, ethanol and R134a. This technology alone and with the combination of ethanol has been used for extracting various herbs. The consistency and the economics have been proven over a couple of decades. Based on that vast experience, COMERG developed equipment differentiated by processing capacity.
For inquiries contact:
Dr. George Stantchev, CEO