Question on How To Properly Decarb Crude

Hello All,

I am looking for help on a protocol to properly decarb crude before short path distillation in a compliant fashion.

We are making thc crude using n butane. We typically are extracting between 50 and 200lbs that needs to be decarbed post winterization and pre short path. For all I know, I’m spot on doing it right already.

After the crude is extracted, we do a two stage winterization at -80 and then toss it in our 20L rotovap. From there I jack the temperature up to 90C and let it ride for about 45 minutes or more depending on the equipments availability/throughput. This is my decarb process.

From there we put the crude in the short path, pull a deep deep vacuum and start increasing the temp slowly. During the temp increase, the crude tends to spit up into my head and sometimes it’ll end up in my condenser which isn’t optimal. We use a Summit 45/50 shorty head.

Thanks in advance for your time and consideration.



@BreakingDabs @spdking

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If you have an oven that can go to 250+ deg F that would be much better than a roto. You are not fully decarbed or you wouldn’t spatter. If you have a vacuum oven it’s even better. You throw it in and cook it (start the reaction) then every one to two hours break vacuum and stir. Do this till bubbling stops completely. You’re able to do this on a hot plate or In your spd. Just hold at 120 C for a while til it’s calm then bring it up to 140 and hold til it’s calm. This can take up to 6 hours for a decent sized load. Once you notice the small bubbles stop forming it’s time to distill


Change your fluid to duratherm s and reprogram your roto to go jotter and crank it to 140-50 and decarb completely


as has been stated, you are not fully decarbing your material in your roto

volume dependent, but a 20L pot @ 90C for an hour isnt nearly enough. at 90c try 4 hours. for 45 minutes try 140c

do what you are doing now, but finish the decarb in your still before you pull deep vacuum and attempt to distill

basically ramp your pot to like 140c, once youve pulled any solvent or low boiling impurities and finished the decarb (no more bubbles) switch collection flasks and pull deep vacuum at 140c, youll be decarbed and degassed, ready for a heady distillation.

to hone this process in order to save time/money/product quality, i would suggest tracking your decarb process with analytics, and experimenting with a couple different temperature/time gradients to find what gives you the best results.


Thanks for the advice. Any idea on how to re-program a 2019 model AI UL listed 20L roto?

Purge and decarb in the spd bf and mantle.

Super super easy


I don’t disagree (this is what I typically do) but it takes up the use of my spd when it could be used to distill product. I want to decarb before it goes in the BF or at a bare minimum, before it hits my heating mantel for my SPD. I want to use SPD for distilling, not decarbing. Make sense?

Then you loose product in the rotovap bf as the oil will he decarb and purged. This leaving lots behind. This is why I finish up in the spd bf. No other transfers but 1x (roto bf to spd bf)


So your suggesting to NOT use a vacuum during decarb in SPD?

Basically do the roto vap to boil off ethanol, put crude into boiling flask of SPD turn it to 140c no vacuum and let it do its thing to decarb. Then pull to a vacuum after it Decarbs and proceed as usual?

I would suspect that once I have it at 140c and I pull a vacuum after it decarbs, it’s going to boil violently. Am I completely wrong? I assume this because of all the other volatiles that have yet to boil off and previous experience pulling a vac after my temp is too high.

Thanks in advance for sharing your experience and knowledge.

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What do you mean I lose product in the roto boiling flask? The crude is already in there anyways. That’s where I boil off my ethanol anyways, then decarb then to spd boiling flask. I didn’t describe that properly in my original post so maybe it was an understanding or maybe I am missing something in your explanation. Either way thanks For your time and knowledge!

Its been awhile since i did it , but you push in the dial and it will bring up a menu. Call across i dont want to give you the wrong info but you just have to reset the max temp and as long as you tell across that your aware that you cant use water they will tell you how. I just dont remeber rhe exact sequence but if you wanna play with it it might be obbious when the menu comes up i just havent done it in 5+ yrs or so

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I lose 25-35 grams in a 20l after i empty it, just get a pair off oven mits or i use the ove glove.

By pouring the rotovap bf, you will loose out on what ever doesnt pour out.

My other option I’ve demo’d is putting the roto boiling flask in my forced air dryer from across at 150c for 30 minutes then pouring that into the BF of the SPD. This does NOT involve a vacuum, just heat.

But that’s inevitable no matter what way you cut it. I have to vaporize ethanol in the roto either way so it’s already in there so what’s it matter? Unless I’m missing something.

talk to AI. they can email the fine manual. they don’t post them on their website because they want a serial number to get you the correct manual.

If you pour the rotovap bf while leaving a bit of solvent, it’s easier to pour and little loss this way.

If theres an easier way, I’m all ears. This is the best way I’ve found.

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You could do my tek of putting BF into a forced air dryer at 140-150c which gets the liquid in a think state and easier to pour post decarb. Pour it out into spd bf. From there you could add a little ethanol to rinse out the remaining amount into the SPD BF or pour/leave it into the next roto vap batch depending on cross contamination and whose batch is next.

Sorry, but if I can save 20mins x 6x that’s 1hr I can do other work in the lab. I’ve found a way that is quick and efficient with minimal loss.

if you (partially) decarb in the rotovap, you’re also removing more solvent. so transfer may be more difficult. decarb reduces viscosity, as does heat, so decarbing fully at 140C in the rotovap may alleviate the potential transfer losses.

decarb under vacuum (rotovap or oven) has some advantages; less oxidative damage, and more thorough devolatilization

decarb in your SPD is also simple and convenient…its right there and ready to go once it’s decarbed. there are trivial visual cues for when it’s done.

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