Jessica McKeil   |   June 26, 2018

An Exploration of Short Path Distillation of Cannabis

Distillation becomes another invaluable step towards a better understanding of individual cannabinoids.
Jessica McKeil is a freelance writer focused on the medical marijuana industry, from production methods to medicinal applications. She personally found relief through cannabis for the treatment of her panic and anxiety disorder. She is lucky…

 

Short path distillation is an innovative process of cannabinoid separation and recapture. It’s highly technical but has recently become a crucial step in the production of cannabis vape products, edibles, and other refined cannabis products, which require higher purity than which is achievable through conventional extractions alone. Cannabis isolates, also known as distillates, may be the tipping point towards full pharmaceutical preparations of cannabinoids from whole-plant origins.

The Basics of Short Path Distillation

The distillation process and equipment are some of the most specialized aspects of commercial cannabis production. Root Sciences and Pope Cannabis Distillation are only some of the brands explicitly targeting the cannabis industry with commercial grade short path distillation equipment. Due to the steep learning curve on all aspects of the distillation processes, most brands provide onsite setup and training for their products. There is no such thing as plug-and-play commercial distillation equipment.

Rosin extraction notwithstanding, most popular extractions methods used in the cannabis industry all rely on solvents such as butane, ethanol, and pressurized supercritical CO2. The chemical compounds in cannabis, including the many cannabinoids, terpenes, and chlorophyll, dissolve in the solvent and through the process of evaporation, separate from the unwanted organic plant material to produce a concentrated final extraction. Cannabis extractions are the input material into the short path distillation system.

The critical difference between extraction and distillation is the question of purity. Petrochemical and CO2 extractions contain a higher potency of cannabinoids than the raw flower, but much of the unwanted plant matter remains. An extraction contains roughly the same cannabinoids as the raw flower, just in higher concentrations. There is no compound isolation.

The premise behind short path distillation is a molecular separation of unique compounds through a process of slow thermal heating. Each compound in cannabis has a different vapor pressure point or boiling point. The vapor pressure temperature is unique for each cannabinoid, terpene and any other chemical compounds. Through precise temperature control of the distillation process, producers easily separate a cannabis extraction into one or more high-purity formulations. Typically the final materials produced through short path distillation include one or more cannabinoids, one or more terpenes, and any leftover waxes, sugars, and heavy residues.

While distillation works in conjunction with the traditional solvent-based extraction methods, it relies on a slow thermal separation instead of needing any additional solvents. Depending on the final purity desired, producers can also follow the initial distillation with a subsequent round. Each round removes more impurities, clarifying the final product even further. Some producers have recorded purities of upwards of 99 percent. With that said, there is some concern that the quality of the product entering the distillation process will dictate the purity of the product coming out. Some pesticide residue may remain even after distillation.

 

The Pharmaceutical Application of Short Path Distillation

The addition of short path distillation to cannabinoid processing can produce purities of 95 percent or more. As is the case with other marijuana preparations on the market, the most common cannabis distillates are the primary cannabinoids: THC and CBD, but there is a growing push to understand and isolate the lesser-known secondary cannabinoids as well as the terpenes.

Whole plant cannabis preparations are experiencing a revival, thanks to a better understanding of the synergistic effect between the dozens of known cannabis compounds. Based on our current perceptions of the entourage effect, it's only logical to question the need for higher purity isolates. Are isolates crucial to the future of cannabis medicine? There is still a case to be made for distillation for pure pharmaceutical preparations of the plant. Distillation offers a way to produce medicine with a controlled synergistic effect.

Separating individual cannabinoids into near-pure formulations is one step closer to the creation of specialized pharmaceutical preparations of cannabinoids. With further study and perfection of the distillation process, medical teams can personalize medicine to the patient and the disease by combining isolated cannabinoids and terpenes as needed. Of course, there is a long way to go before researchers fully understand the intricate relationship between the individual chemical compounds of cannabis and the endocannabinoid system, but distillation is a crucial element to that process.

Short path distillation is now also evolving with the growing demand for pure secondary cannabinoids and terpenes. Producers are moving away from 99 percent pure THC isolates, and instead focusing on the isolation of novel cannabinoid and terpenes. Now, instead of removing the terpenes completely, they are often separated from the unwanted plant material in an external chilled collection flask, only to be incorporated into the final product. Producers are developing innovative ways to purify, separate and recombine isolated cannabinoids into interesting formulations. Cannabis distillation is just another step towards better understanding of the individual cannabinoids, their relationship to each other and with the endocannabinoid system.

 

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