Acetone crystallization of THC-A


I use ethanol and then introduce the acetone after rotovapping. That way acetone doesn’t mess up any of my equipment and I can still take advantage of its properties.


So basically I can wash my fresh frozen or dried nug with frozen acetone. Nug frozen of course.
I don’t have a rotovap so can I leave the jar open untill it’s about 1/4 of what it was?
And then you let it sit uncapped for two weeks and the crystals crash out correct?
After the crystals are made can you separate the sauce and crystals and let them sit for a week or so at room temp and smoke them? Please respond someone I really wanna try thing just don’t wanna fuck up. Also what is a frozen flower acetone wash yield average? Direct message me as well if possible


@Skel3tor: biggest question might be “where did you get your acetone?”

have you read the MSDS for acetone?
is there anything else in yours?

do you know how the FDA feels about folks huffing it? (rats actually, and apparently they did ok…maybe.)

Acetone is a great solvent, it evaporates quite nicely. I’m not certain that it’s a safe as ethanol as far as drinking or inhaling it goes, but it shouldn’t be as hard to remove as ethanol, and ethanol can be removed as a thin film on glass.

Having not tried acetone for other than analytical sample prep (strips cannabinoids from flowers, and dissolves extracts wonderfully!), I couldn’t tell you if the sauce can be purged to safe levels. Or levels that are compliant in your jurisdiction, which vary widely. There is currently no analytical data posted here on solvent occlusion or ability to purge from the high terpene fraction.

I urge you to go look those things up before you “smoke” anything you extracted using nail polish remover.

If you’ve got analytical or better solvent, a vac oven, and access to residual solvent testing, go for it!


I bought pure 100 percent acetone it was like 25 bucks for a pint. Legality’s a grey area where I’m at. But I’m just wondering if instead of rotovaping if I can just leave the jars open? And once the acetone slurry is made do I leave the jar open or capped


I appreciate the response. I’m out in the sticks tryna make some diamonds. If anyone has a dummy version/Home version lemme know


All I got is I wouldn’t huff it till I had it tested…but I’ve had a GC since almost day one.

You seem to have all the conceptual bits in order. You will want to leave your jars open and covered with screens by my reading.


You can certainly just leave it out and it will slowly evaporate over time. Once the concentration increases, you will see a film form over your solution.

If you don’t have a vacuum oven, you will 100% be smoking acetone. Your tolerance of that is up to you.


So say I follow this method exactly and I’m left with acetone THCA crystals. What solvent could I recrystalize them into to reduce acetone levels? And would pulverizing them increase the evaporation of the acetone? Do you think the acetone levels would be high enough to egnite in a banger if they weren’t recrystalized or put in a purge oven just air purge? I’m not gunna go out and do it right now I’m just retaining different techs




Anymore insight anyone?


The biggest problem with Home Depot acetone is water content.
Otherwise very pure stuff. A galss slide can be used to do a quick test for residuals. If none are present ,you’ve got good acetone at a fraction of the effort of going the reagent grade route.
To get rid of the water (to get anhydrous acetone)

  • 1L container of acetone.
  • pour out about 1/4 of it into another container
  • add magnesium sulphate (epson salts)(MS)
  • leave overnight
  • quickly filter into a new container and seal immediately. Coffee filter works just fine, the MS is insoluble in acetone.
  • the MS will turn into a globby mess, or not, depending on the water content.
  • Note that exposure to air will result in immediate absorption of atmospheric moisture. Acetone is hydroscopic. High humidity is not the right environment to do this. If you are really fussy, use an N2 blanket.


Seems like it kinda depends on what you’re going for. Heptane, pentane, possibley even butane if you can get the temps right and supersaturate the solution then cool to crash or slow evap depending on what kind of formations you’re after.


In most cases i’d say crush the larger crystals if made with a solvent that can be difficult to purge. Should be no more difficult then removing ethanol from your crystals or extracts since the acetone evaps extremely easily once exposed to heat and vac.


Will acetone mess up the terpenes?


Acetone will not mess with the terpenes. Acetone evaporates easily at room temps, and under a vacuum it will evaporate pretty quickly.

In my experience, pouring off the terp sauce layer and purging the xtals in a vac oven will bring levels below sensory threshold quite easily. Even without crushing. You will inhale more acetone while working with it than you will by smoking the crystals after a good purge.

Acetone is less harmful than hexane and it is listed in the same category as ethanol for solvent class, so even though others may feel different, i feel it is safe as can be. Your body produces acetone on its own when you break down muscle mass but the same cannot be said for ethanol, butane, or hexane.

I have grown some really decent xtals with this method, rivaling what people create with butane but with less trouble and pain. I would smoke my acetone based xtals over butane xtals any day. Just my 0.02.


The acetone from home improvement stores is close enough to pure, any appreciable water content would make it unacceptable as paint thinner.

Purification of Laboratory Chemicals Seventh Edition
Wilfred L. F. Armarego
Christina Li Lin Chai


Is it possible to maybe distill it before using it…just a thought


I have hydrometer readings of nearly all of my solvents, a gallon of acetone I purchased from Home Depot in April of 2017 had a specific gravity of 0.795, the acetone reference I posted above states 0.791.

There are other density values for acetone, Wikipedia states 0.7845, PubChem has two other references at 0.79.

I just retested it, 0.794 @ 68F. and took pics.

The hydrometer states it’s calibrated at 60F, and at 60.0F I read 0.798. Still close to anhydrous even though I’ve taken samples four times and returned them to the container.


Why preference of acetone xtals over butane? Just curious


Its not necessarily a preference. Just another way to get to the same end result. I see people heavily guarding their crystal tech like they are the gods from heaven or something and they make it more complicated than need be. With this method anyone can get into growing crystals with minimal supplies and solvents, making for a better community through hands on learning.

Some people dont have a closed loop setup or a fancy crystallization chamber, or just plain dont want to mess around with pressurized flammable or explosive gasses. I do have these things but i prefer to do it this way because its a lot less finnicky and with practice can produce decent crystal clusters after a second recrystallization.