Ask the Experts: Extraction, Part I: What Is the Biggest Challenge in Cannabis Extraction?

March 4, 2019
Abstract / Synopsis: 

Leading extraction scientists and researchers from the cannabis industry—John A. MacKay, Synergistic Technologies Associates and Brian C. Smith, Big Sur Scientific—participate in this round-table discussion series. This month they discuss the biggest challenges in cannabis related to extraction.

What is the biggest challenge in cannabis extraction?
John A. MacKay: The BIGGEST challenge is:

Botanical integrity is always first. Respect the plant and the compounds that it naturally produces. The anecdotal evidence is from the “whole plant,” not individual compounds. Cannabis includes hemp plant definitions.

Investigate every facet of science. You cannot be an expert in all facets of the plant or the phases of the extraction and separation process, but you need to know enough about each and the interactions between them.

Goals and motives need to be defined. The bigger the boat, the less speed and maneuverability, however also the less it gets affected by the little winds of whim. Know which facets can be varied and which are “non-negotiable.” Motive versus mission versus money.

Get prepared for delays. Licenses, land, electrical, embargos, people, and the unknown are known to be driven toward extending every initial schedule.

Egos and extremism is poison: “this is the only way” or “that never works.”

Solubility. It is all about solubility. Two things to remember: “like dissolves like” and “oil and vinegar salad dressing.” Molecules and compounds do not respect opinions; they adhere to the laws of thermodynamics and mass transfer. It is that simple. It is that complicated—chemistry, physics, and mathematics. You want to have some compounds dissolve in a solvent preferentially over others (laws of thermodynamics), and move them to another vessel for collection (mass transfer).

Test and test and test. Analytical instruments for in-house testing. Good is not a number. You need to know the theoretical yield and the actual yield.  You need to know the rate of extraction. You need to know the entire cycle of the process from seed to shelf, and the cost of manufacturing.

Brian Smith: I think the biggest challenge to cannabis extractors right now is the difficulty we have getting consistent analytical data from cannabis analysis laboratories. Some colleagues and I recently did a round-robin study, which was published in Cannabis Science and Technology, comparing potency and pesticide results across five different labs. The measured THC concentration in the same distillate batch varied from 77% to 94%. Samples spiked with six pesticides were submitted, and the false negative rate was 78%. Two of the labs completely missed all the pesticides.

It is impossible to make rational business decisions about how to process extracts, and what material is or isn’t legal to sell, in the face of this much unreliable and conflicting data. This problem will probably not resolve itself until appropriate standard reference materials are available, and governments step up and require all laboratories use the same analytical method.

Look for part II of "Ask the Experts: Extraction" in our June 2019 newsletter. Our series with experts on cultivation will be launching in April, and part II of our analytical methods/cannabis testing series will appear in May.