Total or Near Total Ethanol Removal

So, I’m sure this has been addressed but I can’t seem to find it. I’m using a rotovap to recover ethanol from my extraction, but I can’t seem to get all of the ethanol out of my extract. I rotovapped it so hard one time that the ethanol in the receiving flask was bubbling (I shut it down immediately). I had one person tell me that it’s not possible to get all of the Ethanol out this way, but I was hoping that someone here could verify, and then possibly tell me exactly how people do get all the ethanol out of their crude. I have seen ethanol crude that is basically hard as a rock until heated, so I know people are doing it.

Use a vac oven to purge the rest out.

2 Likes

Heat & stirrer🤔

Bubbling in a rotovap can be a good thing but you want to control it and make sure it doesn’t get so hot that it bumps into your recovery flask. As for complete recovery, you want to leave some EtOH is the boiling flask so you can remove all the oil. From there you can put it in a vacuum chamber with a heater pad and start removing the left over EtOh so you are ready to smoke it. Cheers.

1 Like

Also you could look into buying a source turbo to do your final recovery :slight_smile:

A simple hot plat and mag stirrer (mentioned above) is 80% cheaper than a source turbo junk.

5 Likes

Decarb it

Seconding. I use https://catscientific.com/purge-ethanol-cannabis-oil-using-cat-mcs78-hotplate-stirrer/ and https://catscientific.com/decarboxylating-cannabis/ and they both seem to work well, though I don’t have access to residual testing.

1 Like

What if it has been decarbed before extraction? (Co2)

Then proceed to de-volatizing or the removal of terpenes.

Just cook it down in a stainless steel pot while stirring. Gradually bring temp to 120 C and then remove from heat. Obviously you can do this in an spd under vac but it’s not crucial in my opinion

1 Like

Yes! I know bubbling in the primary flask is good, but I was getting bubbling in the Etho recovery flask, which I feel like, is not good.

Are your valves shut? Mainly the valve that you use to release pressure in your etoh recovery ball closed? Is the valve also closed where you drain out the etoh to collect? You might have a leak somewhere?

Put some ice on /under that receiving flask might help, if it’s a problem

You can remove all etho with the roto if you choose. I prefer to leave some in and pull it out in the short path to clean all my glass at the same time.

In the roto, after you see minimal etho condensing on your coils at your usual temp, increase your bath temp to 180 f and reduce your rotation to 40 rpm. If your collection begins to boil under too much vacuum, crack the open air valve to close your check valve to the column and begin collecting into the bottom of your condensing column instead. Recovered volume of etho will be minimal, but if too much is collecting, equalize the pressure in the collection to open the check valve and empty the column, then repeat.

This is not a preferred method at all. Short path or hot plate and stir is the best way, to me anyway.

1 Like