Decarbing during solvent removal


Is it possible to be decarbing your extracting while evaporating off a high boiling point solvent like ethanol (not that high at 79c) or heptane (98c). I’d think that a couple hours at 98+ would certainly get the job done?

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You can purge then decarb in the spd bf and mantle prior to distillation. I do it this way.

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Yeah that’s my current SOP :slight_smile:

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Was just curious on the physics/chemistry of it if they’d occur simultaneously

You can’t decarb while evaporating, your crude will never get hotter then the boiling point of your solvent until the solvents all gone


Yeah but if you held the solvent at 102 or so with heptane (it’ll usually be a few degrees hotter than your BP)… You can definitely decarb at 100c+ over a few hours. Maybe not fully? But probably 90+%

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you can absolutely decarb at 78C.

it just takes more time than at 100C or 130C

leave your weed at rm temp for 18 months.
tell me it’s not decarbed.

I routinely saw 100% decarb at 78C when recovering 15gal in 12-13hrs.


I confirm what @cyclopath posted. I used the same system as he did and saw the same results. The trick was not performed under vacuum either.

Hes talking about while recovering your solvent though, that’s not possible. Unless you want to let all your solvent evaporate and wait 2 years rofl

How did you manage to keep your solvent in there for 15 hours while evaporating? Sounds to me like the solbent evaporated then it started to decarb. Alcohol boils at below 78 at normal atmosphere, you boiled off the alcohol then decarbed it it sounds like.

I recover my hexane at 85c on the roto, it doesn’t decarb till the solvents evaporated as hexane under vac boils at below decarbing temps.

Probably a large still could take 15h to remove a large batch of solvent. If it’s held at those temps the entire time during solvent remediation you’d likely be decarbed. Even if the solvent hadn’t fully evaporated.

Dunno though lol… That’s why I asked

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The problem is if you’re evaporating your solvent the solution will never get above the boiling point of the solvent till most of it’s gone. Ethanol boils at 78c at atmosphere, if you’re under vac it’s way lower then that. How will you reach 78c if your solvents evaporating at 50c? You wont till it’s gone. He said it took him 12 hours to evaporate 15 gallons of ethanol, that’s super slow. I can do that in 3 hours max on a roto. I dont understand how you evaporate your ethanol at 78c for 12 hours unless you’re not using vacuum. If you’re at 78c you have to be adding pressure as that’s the boiling point of ethanol WITHOUT vac.

Tbh what he said makes no sense lol you’re evaporating 15 gallons of ethanol in 12 hours at 78c and decarbing? Guaranteed the solvent evaporated. How couldnt it if ethanol boils at 78 c at atmosphere?

If you evaporate 500L of alcohol at atmosphere you could certainly do that. My batches usually take 8h and I do it open to atmosphere on a still.

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If you want to throw your solvent away you can do that, that wont work in a roto though. I thought you were talking about during solvent recovery

nope. I had to finish removing the ethanol in a rotovap…

5 gal in the still would require decarb. 15 gal did not.
it’s all about residence time.

why was that still so slow?

I blame the 1/4" ports on the jacket. and the limited delta T available using 94C hot water.


Was this under vacuum?

No, it was not.

at 78C? how could it be?

That explains it, I bet the increase in pressure raised the boiling point so you were evaporating at a much higher temp then in a roto. That makes sense