Currently, most drying of cannabis is done at atmospheric pressure at ambient conditions for long periods of time, or at elevated temperatures with air circulation for shorter periods. Freeze drying has not been adopted for cannabis drying at any scale other than for research. It is widely accepted among cannabis processors (extraction and distillation) that the supply of cannabis will be unable to keep up with the demand of the processors due to the high quantities of cannabis needed to create one kilogram of THC oil.
Related: Learn about the difference between different cannabis oil derivatives in this blog post, The Difference Between THC Oil, Cannabis Oil, CBD Oil and Marijuana Oil.
This is likely true in the short term as the various government states wrestle with how to control production of this highly restricted plant. Even in those jurisdictions where the use of cannabis has been decriminalized for recreational use, there are strict controls on agricultural production. There is a clear trend toward decriminalization and reclassification of cannabis across most developed countries, and as this trend continues and cannabis production and processing become more integral to the economies of the various states, restrictions on production will ease, production of cannabis as a crop will expand, and eventually meet or exceed the demand of the processors.
Due to the constraint in supply of plant material, maximizing production and profits on that material becomes more important. Currently, there is no urgency to quicken the drying process, but as competition stiffens, the need to process as much and as fast as possible will become more important. Vacuum drying will become increasingly important due to its shortened cycle time. It could even be argued that with a shorter cycle time, less inventory would have to be on hand in various stages of drying at any given time, thus reducing net working capital and improving cash flow dramatically. Also, product turnover could increase dramatically which would have a profound effect on return on capital.
Related: Discover the principles behind freeze drying, and how and why it's used, on our Freeze Drying resource page.
Limiting temperature during processing is generally seen as advantageous to preserving the top quality of the processed oils. Lower temperatures result in clearer and more viscous THC oil.
Note: Highly purified THC oil is clear to very light amber and is thicker than honey. If turned upside down in a jar, the oil will not pour or even slump. It has very little odor. According to Leafly, decarboxylation is critical to react the THCA into THC, which makes the substance psychoactive. Reaction is done at temperatures of 110C to 130C and releases a great deal of carbon dioxide. Decarboxylation happens instantaneously when marijuana is smoked, due to the high temperatures from burning. It is also likely to be less viscous, more like honey. Darker THC oil will not sell for as high a price, though still high enough for enormous profits.
Just how involved is vacuum in this entire process? Well, equipment for drying of cannabis is done in atmospheric, elevated temperature drying ovens and dehydrators made by various equipment manufacturers like Leybold. Check out our product page packed with vacuum suggestions for cannabis processing.
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