Hi everyone,
I am currently running CO2 extractions and winterizing the crude material with 200 proof ethanol at -20oC for 12-24 hours. I am interested in speeding this process up by performing the winterization in a -80oC freezer. Does anyone have any experience with this? Does it speed up the process? I would think that cooling faster would speed up the precipitation of the lipids, but I also know that precipitation/crystallizations are hampered by increased viscosity, and that larger crystals form at a lower viscosity.
Another potential scenario is to use the -80oC freezer to increase the cooling rate, but then filter in stages in order to pull out precipitated lipids, reduce the viscosity of the mixture, and allow the next stage of precipitation to happen more efficiently.
Any insight is appreciated.
Cheers!
Needs a few experiments to answer your questions. I'm not aware of any published research on this specific topic.
Hello, by decreasing the freezing temperature you will precipitate more light components obviously, those will be now removed by filtration from your ethanolic solution.
You may assume that increasing the driving force will speed up the process but this is a point under discussion for many solidification processes with different approaches and not conclusive in this case as far as I know.
You will definetelly increase the amount of precipitated material that will affect your filtration step. To filter in stages sounds a good idea to avoid clogging on filters.
Thank you very much for your comment Laura. Happy to report that we have performed the winterization (lipid precipitation) at -80oC with great results. At -20oC, we saw that the amount of waxes that precipitated did not plateau until about 40 hours. At -80oC, we were able to remove all waxes after 2 hours. We filtered the solution after 1 hour at -80oC, put it back into the freezer for another hour, and then filtered it again through a medium with a smaller pore size. A very small amount of wax was recovered during the second filtration (about 90% of waxes were removed during the first filtration).
Those are great news! good job intensifying the process!! Can I ask which volume are you winterizing and the filter pore size? and if you know the %wt of total waxes removed now with your two stages filtration?
We winterize with 5:1 ethanol to crude v/w. We like 48hrs at -80c. We then filter with celite and carbon.
An Ethanol Winterization below -52c will remove Cannabinoids, Terpenes and Flavinoids along with the plant waxes and plant lipids. -50c would be the sweetspot in Terms of purity and speed.
You can also use dry ice instead of the freezer. This speeds up the process as well.
Hi Richard,
The best technology to use is a filter reactor. They allow you to dial up the exact winterisation temperature you want (e.g. to separate wax, fats, lipids but to retain cannabinoids, terpenes etc). This equipment is pharma, cGMP compliant and scalable. Don't use deep freezers or similar - the results are not of great scientific value. For US / Canada products talk to Cascade Sciences https://cascadesciences.com.
Cheers
Tobias
Tobias,
Have you personally used the filter reactor for winterization? I am checking one out on the site you provided to see if it's worth it but would love some anecdotal evidence!
Thanks,
Amanda
Old post, thought I'd offer some insight.
Richard Augimeri I'd imagine the sweet spot for winterization is around -40C/F for the solution itself with somewhat diminishing returns from there (something to further consider for scaled commodity production). -80C and agitation certainly speeds up the process as this is a brute force precipitation and we have had similar experience completing the process in 1-2 hours. I would be most focused on the final filtration stage at
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