Cannabis oil

Drying cannabis for retail or THC & CBD oil extraction

May 27, 2021


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.

Cannabis drying process: possible pitfalls

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 various 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.

The role of vacuum technology in cannabis distillation and processing

Due to the constrained supply of plant material, maximizing production and profits on that material becomes more important. Currently, there is no urgent need to quicken the drying process, but as competition stiffens, processing 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.

To learn more about the role of vacuum technology in cannabis distillation and processing, click the button below and download our free eBook.  

Depending on the application, the environment, and the characteristics of the products involved, vacuum pump requirements can change significantly. Processors who want to get the most out of their pumps need to understand all the factors involved and combine them to create harsh conditions for pumps.

Performance capabilities, initial cost, and total cost are all part of the calculus, as they are for other pieces of the production line. All of those need to be clearly defined before purchasing decisions are made, and they need to be based on the best information available. As just one example, being able to accurately project the frequency of oil changes required on wet pumps in a freeze-drying environment can make a big difference in its total cost.

"Once that determination has been made, then the question becomes whether current pumps are meeting production demands and what changes need to be made if they are not," says Ligman. "That will most likely mean having to take down a production line to replace pumps with models that are more suited for the specific application. That's not an easy decision, but it is a necessary one to maximize production efficiency."

"One of the hardest things for a company to do is to take down their production to make a change to it even knowing that they might get a better result after the change," says Ligman. "It's difficult to take down your production line because, during that time, you're running behind on your production. You're losing money, and you're running behind, you're building up a backlog, you're putting pressure on everyone. It's a hard decision to make."

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