Cannabis extraction: what is the PBX-Standard?


© iStock-Елена Рубан

In this report, PURE5 discusses its innovative Pure Botanical Extraction (PBX-Standard™) method to create clean, high-quality cannabis extractions.

Pure Botanical eXtraction is the acronym for liquified gas extraction technology that behaves as CO2, leaving no residues in the final product. PBX extraction is performed under a controlled environment without access to air or other contaminants. Unlike other methods, PBX extraction process has no chemical reactions resulting in oils with no undesired by-products, without altering taste or flavour. PBX employs a non-polar media that behaves as a hydrocarbon however non-flammable and extracts only the oil without altering the remaining components that can be used in sequential processes, for example, in food or additives, supplements, and post processing.

PBX is gentle to the botanical while performing at room temperature and preserves all natural enzymes. It does not degrade the components extracted or left behind, and is so selective that it extracts only the resin compounds without the need for post processing, such as winterisation or filtration. That makes this extraction more superior than the known three major methods: by non-selective gases like CO2, chilled alcohols, and variances of hydrocarbons.

The technology has been promoted by PURE5 for over a decade and is known as a high-terpene, strain-specific, low pressure, liquified gas extraction process that is safe, automated, and precise. It has been utilised for botanical extraction of food, fragrance, and flavours, as well as for essential oils for decades.

The PURE5 Extraction Technology is guarded by at least four international patents protecting equipment and the process. The process is registered for food extraction and is GRAS (‘Generally Recognized As Safe’) by the U.S. Food and Drug Administration (FDA). PBX is a gentle process at room temperature separating the cannabinoid and terpene constituents from the raw plant material, without burning or freezing, and while still obtaining the most out of the plants. The PBX-Standard process is a game changer in the industry for simplicity, safety, and quality.

How does PBX work?

The PBX-Standard™ eXtraction technology has been developed to overcome all the disadvantages from using lower density liquified gases like CO2 for resin extraction while maintaining all the benefits of liquified gas extraction being solventless and resulting in no residuals in the extract.

It is known that the polar nature and the low density of CO2 can only extract constituents in the supercritical phase when the density allows, although in the supercritical phase it does not extract terpenes. Dropping the pressure to high sub critical pressures exploits the polar nature of CO2 allowing for limited terpene extraction. Recently the fight for the solventless nature of CO2 was lost, as most of the CO2 manufacturers officially adopted ethanol as a cosolvent.

Professionals working with CO2 know that CO2 extraction does not perform well with fresh material, as the water-gas connection brings undesired acidity levels in the resulting extract. Unlike CO2, PBX is inert, odourless, non-toxic, non-flammable, non-corrosive, and does not form acids in the presence of moisture. This broadens the scope of applications to include many pharmaceutical products that are pH sensitive. PBX-Standard eXtraction is performed at room temperature overcoming thermal degradation or loss of volatile compounds during isolation. The inherently low boiling point of the gas eliminates the need for complex and slow recovery.

Fig. 1

PBX has been designed to exploit the natural properties of R134a (tetrafluoroethane) gas creating the perfect process where we perform, like the way CO2 gas behaves in the low sub critical mode. The small non-polar molecule size and the inert nature of the R134a gas efficiently penetrates the plant tissue thoroughly extracting the oil soluble fractions. PBX extraction is performed at room temperature and low-pressure conditions with resulting oils being seamless to the full-spectrum resin delivered from the plant.

Full-spectrum terpene profiles are collected without degradation of molecules and are easily separated from the gas. PBX is the perfect choice to extract fresh cured botanicals leaving solids (lipids and waxes) behind. R134a is hydrophobic resisting all water phase components and in most instances, winterisation may not be required.

Our machinery performs a very simple three step process that is fully automated to the operator and guarantees consistency of the product output. Load the biomass, gently soak, and wash the vital oils at room temperature and low-pressure, then gently evaporate the gas so you can collect your precious oil that can be used directly in your finished products. The entire process for extraction and separation takes approximately two hours.

We added a second input column to our systems which significantly increases throughput by minimising recovery time. Any trapped gas in the output is 100% removable from final oils without imparting flavour or tint. Traditional solvents oxidise when exposed to air, imparting flavour that is impossible to remove from your final oils.

What is the science behind PBX?

The science of extraction is very simple. Similar components extract similar components, and it is important to know the target group of compounds to be. In the cannabis flower we will be looking at quite wide group of ingredients starting from the hydrocarbons which are all mono-, sesqu-, di- terpenes, saturated, and non-saturated alcohols, saturated, unsaturated, and aromatic ketones, saturated, and unsaturated aldehydes, and ending with some saturated and unsaturated acids. In brief the terpenes, ketones, aldehydes, and acids are building the composition of the full-spectrum cannabis oil.

To extract the combination of those, a solvent needs to be properly selected. The botanical ingredient diagram below shows those target ingredients in red in the entire range of plant ingredients and various solvents that can extract them. There are three main groups of solvents by the target group of plant components: oils called oil solubles; the flavones; alcohols; and acids, which are known as alcohol soluble; and tannins; minerals; and pectins that are known as water soluble. That puts our solvents in three major groups mainly differentiated by their polarity.

Fig. 2

How the polarity works

The solvents are complex organic chemicals that consist of molecules. The molecules have various shapes and special configurations which, depending on their bonding groups, may be more symmetrical or disproportional. In general, if the distribution of the electrons between bonded atoms is even, the molecule is non-polar or if it is uneven, it is polar. Polarity is a description of how different the electrical poles of a molecule are; therefore, the electrical potential of the molecule is different. So, polarity forms a scale depending on the electronegativity of each bonded atom in the molecule.

For example, the molecule of water has a large oxygen atom with atomic weight of 16 and two small hydrogen atoms with a weight of 1, and the water will have extremely polar performance as a solvent. As we see it from the chart, the water extracts polar plant ingredients located on the right side of the table. Then a hydrocarbon will have a very small inert and symmetrical bond between carbon and hydrogen, and it is a non-polar molecule that will extract the ingredients on the left side also called oils and oil soluble.

Usually, those non-polar ingredients are very volatile and have a boiling point below 20°C. Also, unfortunately due to volatility, most of those chemicals are extremely flammable. So when used as a solvent, strict safety precautions have to be considered. The next group of solvents are the alcohols, and their molecule is much more polar but still, their…


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