Cleaner crystals

Trying to get some more info on washing crystals in pentane or other solvent to looking to get crystals with no terps would I wash crystals with cold alkaline like pentane on coffee filter? Can a regular pump handle that or would it be to dangerous?


needs more info on the pump. Generally speaking, since Alkenes are more corrosive on the seals of most pumps, it is advised to A) put a cold trap in line sufficient to recover the Alkene ; B) use a vac pump rated to handle flammable vapors (as the seals may corrode and the vac effluent may be flammable).
a regular pump can work, tho danger exists. def would want a cryo trap, or 2 (if your pump is has oil) .

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Okay I been asking around alot, pentane ,heptane the main ones, I’m trying test run with 100% ethanol,… The idea is to use buchner funnel w vacuum aspirated water or some sorts, that way solvent passes through crystals fast, put on fast filter paper. Do it fast and get everything super cold with dry ice, if using pentane or heptane u must get hplc grade or you’ll have to distille it then get some sort specs done to make sure safe to use. If you have distalites kit you can reuse the solvents. Any more questions?

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That should get you started, if you use pentane or heptane make sure hplc grade or you get cancer or something awful one day

I’m attempting this weekend with the ethanol…I started out looking at hexane, but after much research and help from ppl on here that’s the best info I can give, the ethanol will eat some the crystals, where the pentane is best and heptane next if hexane just make sure hplc

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Thanks Guys I’ll give that a try and keep you posted

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And really I would stay away from hexane, after talking to some more ppl pentane and heptane the prime choice for washing


Definitely post an update-would love to hear more about your process and see before/after crystal shots!

I’ll be attempting washing couple grams tomorrow with dry ice cooled pure ethanol, I’m probably gonna lose some but I’m just curious till I can afford to start buying pentane hplc, pretty sure that’s the same stuff I can use to melt and regrow the crystals all as one big one too, but that’s another day


After washing those crystals today with pure ethanol, I definitely lost some, actually more than half, it washed pretty close to clean, I had to do several passes, I do feel like something like pentane or heptane will be my next choice.
Before 2 g

After not weighed yet still damp I’m sure, I folded filter paper over and used paper towels to dry up any that would come through the filter paper… They look great, just wish it wouldn’t have dissolved so many… But i was expecting this

So @Otscc and @Future. Will using pentane and heptane greatly increase my return and minimize my loss. All the equipment I have is cheap ass buchner funnel with fast filter paper and water asipirator. Repeat I know using ethanol was bad. I was having hard time finding source for hplc grade pentane that wouldn’t need any extra prep and wasn’t super expensive, not license business… Also I have no experience using a funnel like this, I don’t even know if I did correct with all the variables…I watched couple videos but they was just how to use the funnel in general, not really on how much to apply, do you let pool, no, if not I couldn’t get the color off without pool. Thanks again all.
Soon I have budder question for you big heads, not how to make just what’s happening, been getting it together with pics though bc happens every time I just purge mother liquid to long during shatter runs, thanks another day another time

Use dry ice chilled pentane or Heptane. Your filter setup is correct, but leave the vacuum off and pour the cold Alkane over the crystals ntil they are submerged. Stir and then pull vac.

By chilling the Alkane we are reducing the Cannabinoids solublity


Great I use dry ice but with destructive ethanol I guess I dissolved a bunch of them, and I had to vak already hooked up when I poured so next time I’ll try it like you said,

Thank you much

And I don’t want to confuse anyone need to make sure you get hplc grade for any lab grade reagents solvents don’t want to get any bad contaminants from it not being clean enough… Hexane supposed to have stuff that lays heavy in the body, that can’t be good

You can get plenty of cancer and neurotoxic damage from HPLC grade heptane as well. It will be interesting to see the health effects of extraction technicians who didn’t use fume hoods in 5 to 10 years.


If I am understanding you correctly, it sounds like you are doing it wrong… If you want cleaner crystals then you should do a re-crystallization step instead of trying to just “wash” them with solvent over filter paper.

When you crystallize, you are excluding undesirable components. You can repeat crystallization to increase the purity of your crystals. You want to completely re-dissolve your crystals in a solvent, and then crystallize again. The resulting crystals will be more pure. You will lose a small amount of your target compound each time you recrystallize, but you will lose way more of the compounds you don’t want. Probably re-crystallizing 2x at most would be sufficient to get some really nice clear crystals.


One might even expect to get cleaner crystals simply by evaporating off most of the ethanol that was used to “wash” the above batch.

I know THCA can be crystallized out of ethanol…I’m assuming there is a good reason most folks don’t do it that way.

Other than the adrenalin boost mason jars and butane provide :slight_smile:


I would guess the fear of accidentally decarbing when evaporating off ethanol? I’ve never recrystallized in ethanol but I’m sure it would work very well.

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Exactly this. Here are a couple recent examples of mine. Sugary crude oil was dissolved in boiling hexane, then allowed to cool. First picture was about 16 hours in, while the second one was about 24 hours.

I dissolved the first sample with a stir-bar (its surface was coated in crystals before anything, as expected) and it seemed to crash a little more heavily. Right off the bat, but not as much clarity to the crystals. The second sample had no stir bar and did not seem to crash as much quantity of THCa right away, but the crystals are much more uniform/pure in appearance - like little snowflakes.

Of course, note the difference in “solvent : crude” ratio.

20 g Hexane : 60 g Crude

20 g Hexane : 90 g Crude


ReX and washing are two separate things.

If you are looking for ultimate purity, it’s best to smash and wash.

If high purity and large crystals are the goal, a ReX is suitable