Safe to purge residual ethanol in vac oven?

Quick Q. So we noticed after rotovaping we still had a little ethanol left in our compound. After researching that on here it seems we are doing the right thing as far as rotovaping. So I’ve been putting my jars in my vac oven, and pulling a vac at 105 degrees F. I’m getting quite a reaction out of some jars. I just want to know if I’m damaging anything else or boiling anything else out besides the ethanol, but I’m pretty sure it’s just ethanol.

that will work.

I recommend secondary containment (a pyrex dish to catch spills when the jar boils over).

although back in the rotovap would make more sense.

sure, at some level you are boiling of terps. that might be a good thing, depending on your desired endpoint.

where are you going with this?


I use a vacuum oven set to 250°F to decarb my crude after I take it out of the roto using a 5L beaker. I keep a cold trap on that oven.


We are trying to eventually get them into carts whatever material looks/smokes good can go in, any real crappy product is going to short path. The first time we loaded up pens with this oil, they smoked good, tasted good, but eventually turned green. (See my post about the pens turning green). We eliminated all variables and tested the jar samples and could not reproduce the green. Only when they were in the pen for a week they turned green. The only last idea we had was either residual ethanol was stuck In the pen/oil and reacted. Or there was something in the pen from the manufacturer. So for now, we’re just trying to make sure there’s no ethanol in it anymore

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The reason we don’t put it back in rotovap is because eventually it gets so thick in there with minimal ethanol return. Half of it gets stuck in the flask. So we figured dump it out of the flask as it starts getting real thick, and do a final purge on it in the vac oven. And judging by the reactions, it seems there sure is ethanol coming out

what temp is your roto-bath? turn it up to 90C before you pour…

or invert flask and use a heat gun!

I’d bet money it is a chemical reaction with something IN the carts.

edit: we purge butane in a vac oven. WTF would you ask if this was safe?

What exactly do you imagine the issue to be? (other than you didn’t use secondary containment, and might boil it all out of your jars onto the oven floor?)


Rotobath is at around 100f. And we do use the hot water or heat gun method but still, eventually it gets so thick and ethanol starts running very little if all. And when I asked if it was safe, I didn’t mean in an explosive way… I meant for the compound. I didn’t want to be boiling out anything else. And I mentioned I’m just trying to clean up a lot of crude trim oil for pens.

I don’t think there’s any problem, I was simply asking if my temps and vacuum pressure was proper to boil out any residual ethanol that’s all

once can make ethanol based shatters in a vac oven. it’s not required, but it helps.

you will absolutely loose terpenes, but if you want to meet residual solvent limits, you’ll need to suck harder.

that can be done in a rotovap, but you’ll need to turn it up higher.

if you haven’t decarbed your oil, then removing ethanol to state mandated limits will give you a very viscous, if not solid product (see shatter above). I find that decarbing under pressure will THEN yield a decent vape pen.

not playing by any rules? those pens you’ve been making are above 5000ppm ethanol. I’ve only submitted one sample for testing straight out of the rotovap, and I don’t recall the numbers, but it was well above 5000ppm.


Yea as of now these products don’t need to be subjected to testing or anything. Just experimenting. As crazy as It sounds, the
Pens we made with the oil right out of the rotovap were enjoyed by the people we gave them to to try. I know it’s trim oil, but we managed to clean It up pretty well. The final product was Good for our purposes, it was just that damn green issue… that and all the convectium pens leaked. But that’s a hardware issue and it’s easier to trouble shoot. today’s inquiry was just wondering if I was using a effective and “safe” method for boiling any ethanol out of our oils to exclude that as the green culprit. After this ethanol purging, I’m gonna load up a few different types of carts and see if it happens again. Thanks for all the replies this far

We take the miscelle as rich as it can go while still being able to pour out of the 5L RotoVape. Transfer that into silicone pie moulds and purge at just under 85c with cold traps before the vacuum pump. After the ethanol is gone we decarb in toaster ovens at 125c for half an hour. Then onto TW.


Why do you add distilled water in this process?

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to drive the last of the ethanol out without raising the temp and burning the extract.

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Is 90C decarbing your crude?

From the other theads, I didn’t think pressure had anything to do with reducing decarb temps which I thought were around 230F - 260F > 90C

No. I’m stating that non-decarbed crude will be too viscous for pens, if the ethanol has been removed to state mandated limits.

I saw you over in Decarb under pressure to retain terps?

but you seemed lost makes a pressurised decarb machine that they claim maintains a faithful terpene profile.

are we on the same page now?

Just had misunderstood what I read. Been looking for a good decarbed method that doesn’t yields burnt or tasteless oil.

If I read that thread correctly, people concluded that pressure does not change decarbed temp.

google bomb calorimeter.

then build a small bomb decarboxylator.

@cyclopath is correct, " to drive the last of the ethanol out without raising the temp and burning the extract."

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that is the assumption. it shouldn’t.

However, if that was what you got for the take home, it seems like you’re missing the point.

I was not trying to alter the temp at which decarb occurs. The object of the game was to keep the terps from evaporating. So the now reduced viscosity oil will taste better in a pen than oil that was decarbed at atmospheric or reduced pressure. IMO it does work.

certainly the folks at harvest direct are believers.


I did indeed experience a super thick product at the end of this process. I for sure removed the solvent, and the it seems decarbing process began. Sorry if anything I say sounds incorrect, I’m learning as much as I can. I poured the oil in the jars into Pyrex dishes for surface area, and continued keeping them in the oven at 105F under vacuum and was getting a LOT of reaction. Eventually it would stop completely, but if I stir up the oil in the dish, and pull a vacuum again, it would go back to bubbling like crazy. Sent a video to beaker and he suggest it’s decarbing and to continue to stir and decarb. I hope this will reduce viscosity, because indeed, it’s pretty thick. Decarbing is something I somewhat still don’t full understand, so I’ll focus today’s research on that