I’ve been thinking about terpene extraction recently and am wondering if it’d be possible to load a rotovap with dry veg material as a way to extract terpenes. Has anyone tried this?
Hey, I don’t use a rotovap for terps. But it is possible. There is a form of cooking called molecular gastronomy, this guy uses a roto to Collect essence for flavoring his foods.
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A steady flow of steam or nitrogen should effectively remove lots of them. I think a shorter path of vaporization would help maintain the original flavor profile with no alterations (possible isomerization of terpenes?)
Edit: I thought you were trying to extract terpenes from a concentrate. You could put plant maerial in there, but a reflux in a vertical cyclinder makes more sense and doesn’t require any moving parts
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Thank you.
I was thinking rotovap because of the possibility that the tumbling action of the rotary flask could help evenly distribute dry heat throughout the sample, vacuum would lower the boiling points, the condenser would do its thing, and could flush with nitrogen occasionally to drive volities out of the flask.
Would you be willing to elaborate on the vertical cylinder? Less moving parts sounds great.
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Google refluxing apparatus. D. Gold does a pretty good job of explaining a DIY method in his book; Alchemy of Cannabis. I believe this is what you are talking about Hambread?
And here is a link to D. Golds full book I believe the apparatus is on Pg. 11 (He uses it for extraction but should achieve what you’re attempting?)
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maybe if u got one of those continuous feed rotovap’s you could feed in hot nitrogen. that would def strip the terpenes
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A steady reflux will ensure all the plant material is wetted. If you need to distribute “heat,” use the steam and/or a jacketed column. The taller and thinner the column, the more reflux you will naturally get. At a certain point this will slow you down, as cross-sectional area and volume are very variable (balance is key - like most things in life).
Something like this, but you could replace the hot water with nitrogen as well. And a jacketed column instead of microwave.
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replacing the hot water with nitrogen would have additional benefits too
BetterSteamDistillation5210865.pdf (1.7 MB)
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Such as no losses to water solubility. I would do nitrogen first, then steam (as some heavier, water soluble terpenes/flavanoids may still be present in the plant matter)
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co2 could be another inert stripping gas and if u do “dry” steam it might hav some benefits over regular steam
what do you think think of using a partial vacuum along with inert gas stripping? i mean he’s using a rotovap so matching the vacuum pump of the rotovap to the input of gas is gonna come into play
that’s exactly what I’m suggesting. Regulate a steady flow of inert gas or steam, while maintaining enough vacuum to keep it efficient at lower temperatures. CO2 should work too
yea this is part of the way my new machine is gonna strip ethanol and terpenes. also ultrasonics has amazing possible applications too
The idea of a pre cryo etoh extraction, dry (no aqueous solvents) terp extraction seems to me like it would be a great idea. Especially if the profiles are preserved, one could do several kgs a run, and the terp extracted material could go right into the cryo etoh afterwards.
Heating the inert gas seems like it would be benifical. What about scrapping the roto and vacuum to go with a heated stainless column loosely packed with dry veg material, slowly flooding the column with heated inert gas, pushing volialized terps up and out into a large condenser trap?
im trying something very similar now but for after cryo-etoh extraction to strip terpenes and ethanol. the way i do it is: pump warm water thru jacketed column and wait till everything is at a stable temp. then pull vacuum till etoh starts to boil, with a graphed vacuum vs time chart this is easy. then hold it a vacuum above that while bubbling thru heated n2 or co2. the vacuum level u want is gonna be a moving target at the end but this is only for bulk stripping not for purging.
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Have you found that you’re able to separate terpenes from the etoh after stripping? Curious too about your numbers on how much/ how fast etoh removal, and how low can you go in terms of percentage of etoh left. I’ve been looking at falling and rising film evaporators recently as a way to keep up with CEE
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its tough to give hard numbers cause its a completely blind system and it depends when you stop cause i never go all the way. it also depend how much average vacuum you maintain while adding the n2 and the temp and volume of inert gas flow. im trying to get some equipment so i can have a better answer but right now i have no flow meters and im going by the temp of the outside which isnt accurate to whats inside usually. “boiling” make the solution colder so if u gotta watch that and watch bumping or either nothing will happen or it’ll all come over
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Sounds worth trying… as in it’s now on my list 
As others have pointed out there are other approaches to performing essentially the same trick, but making this work in a rotovap seems doable to me. I’ve heard using a vac oven proposed as well.
Low temp and inert gas backfill seem vital for maintaining integrity of captured terpenes.
I would consider following GW pharmaceuticals lead and kiefing first to increase your per/run yields by allowing you to fit more active material into whatever vessel you end up using.
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Are those chromatograms hand drawn?!?
Nice of them to to be so specific about the temperatures, and explicitly state elevated pressure.
Leaves the rest of us all sorts of room to wiggle past…
Lipase treat first, decant, isolate terps & cannabinoids via vacuum with nitrogen backfill. Hmmmm…
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