Fascinating Botanicals, Challenging Residue

In contrast with animals, plants don’t poop. While plants may release volatile chemicals, like pheromones and fragrances, more often they produce and store a wide variety of complex compounds. These chemicals may be useful not only to the plants themselves but also to people. Refined plant materials or extracts are often referred to as botanicals. Cannabis products include recognizable, attention-grabbing botanicals. The molecular structures of the components and metabolites are aesthetically interesting. In cannabis processing, critical cleaning of mixing and processing equipment is a must. Removal of cannabis residue can be an exceedingly difficult task. Successful cleaning requires an understanding of the basic principles of critical cleaning.

Plants are powerful. They are useful; and they can be exasperating to work with. Learn about the difficult cleaning issues and achieve productive manufacturing.

Powerful plants
Over the course of my childhood and my career, I became aware of the challenges and opportunities associated with chemicals derived from plants. My Uncle, Dr. Jacob Julius Berman (known to me as Uncle Doc), was a prodigy and an amazing clinician. His medical career started over a century ago, during the last pandemic. As a life-long student, Uncle Doc would talk to me about medical research. Forget “Cinderella;” never mind about “Snow White and the Seven Dwarfs.” My uncle recounted tales of pharmaceutical manufacturers searching remote areas of the globe for plants containing chemicals that could cure disease. Plants with super powers? I was so impressed that I did graduate work in plant biochemistry at Rutgers University.

Stubborn residue
In the mid-1970s, as a research chemist for a large clinical laboratory, I was tasked with designing a clinical test to quantify levels of cannabis metabolites (i.e. a “drunk test’ for pot). Even at ambient temperature, the pure material used for the standard stuck to everything. Transferring the yellow goop from a pipette to a beaker was an adventure; cleaning the glassware was a nightmare. If the glassware wasn’t clean, the tests would not be accurate. In fact, achieving clean glassware such as mixing and extraction vessels for lab testing is essential for success in all testing. While the test was never introduced (contact me to discuss the many reasons for the decision), the project probably shaped my thoughts and ideas about critical cleaning and precision cleaning.

Universal cleaning challenges
Meeting the challenges of removing residue of complex botanicals is important in process control; and the lessons may be valuable to those involved in developing and controlling production of complex pharmaceuticals. People involved in many areas critical product cleaning can also learn from the challenges encountered in cannabis production. In fact, cannabis residue in some ways resembles the caramelized residue of left by metalworking fluids.

Cleaning agents from plants
The fundamentals of cleaning apply to a host of manufacturing and processing applications. Heat, force, and elapsed time prior to cleaning combine to make residue difficult to remove. Understanding the roles of steps in the cleaning process – washing, rinsing, and drying – is essential. Plant-derived materials can be used in cleaning agents. Two examples include d-limonene and esters derived from soy (methyl soyate). While the cleaning agents are useful in removing certain residues, such cleaning agents can themselves leave residue on the part and therefore require extensive rinsing either with water or with and organic solvent.

More help
Some plants yield chemicals with superpowers. While these chemicals have desirable properties, consistent processing involves critical cleaning; and critical cleaning requires practical education.

To learn more about aqueous cleaning to remove adherent residues, such as those from cannabis products, attend the PQCW Webinar by Michael Moussourakis on March 31. To learn more about the fundamentals of critical cleaning, attend the Product Quality Cleaning Workshop in May. PQCW is a collaboration between the Cleaning Research Group at Sam Houston State University and BFK Solutions. Details about both the PQCW webinar and the virtual interactive workshop can be found in the “Knowledge is Power” section of this issue of Clean Source.