EHO white precipitate, strange reaction

I am wondering if anyone has seen this before. White chalky residue precipitating out of crystal clear tincture when reduced in the rotovap making the crude milky and creating a white chalky to semi granular looking residue in the rotovap. This happens when I try to colour remediate with Activated carbon over a celite bed. My process is to extract at -80 with ethanol , rough filter and then building a cake of celite 545 on a 5 um SS frit and sending carbon slurry over it under pressure to clean it up. If I don’t try to colour remediate with carbon and celite it finishes transulcent with no chalkyness etc but darker than I would like. I don’t think its the celite 545 since it is not visible in the colour remediated tincture and only precipitates when rotovapped down… What could I be missing? I have seen posts where people have suggested the carbon making its way in there could be the issue and others that say pH may be playing a role.

THCA or Sugar.

one dissolves in water. the other in ethanol

you decide

edit: TLC is simple too…


Looking at the pictures and reading your description, I am still curious about which primary cannabinoid you are extracting and what percent decarbed (approximate is fine) the crude is.

My initial thoughts are that you are getting passthrough of some media, it is acting as a nucleation site, and what you see in the jar is looks like (as @cyclopath suggests) THC-A (sugar) or actual sugar (most likely the former). The white residue on the orb is what really makes me think there might be media in there, but I’ve been known to be wrong plenty often. Haha

Have you done solubility tests (separately for the residue in the orb and the crystaline structures in the crude)?

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totally agreed.

if it’s THCA, it’s because there are media fines in there acting as nucleation sites.


Do you think so? Its like talc on the inside of the rotovap. y coworker tasted it lol and its salty. Also turns chalky when dry and rubbed between my fingers

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building your cake correctly is important.

with only a 5um filter in there, you are almost certainly getting media in your flask. throw a 1um filter paper on the disk, and then build the cake correctly.

see: CRC taste like shit change my mind - #594 by cyclopath

be sure to follow the link to @TheLostBiologist’s tek.

its not about “washing” the media, it’s about running the fines back through the bed so it “sets” correctly and will filter finer.


I did let some particulate settle out in a separation flask and noticed it to be water soluble . It maintained its structure in ethanol but dissolved quickly into an opaque solution in water

I was wondering about adding a filter paper to the top but haven’t had a chance to source some yet. I will try that. Also point taken about setting the bed correctly. I HAVE been “washing”
it and not running the fines back through

If you have particulate settling out of your tincture, again, leads me to believe there is media in there. I haven’t tasted celite, but I know that bitter (cannabinoids) or sweet (sugars) should be all you ever taste.

Salty is concerning and leads me to believe consumption (orally consumed or inhaled) prior to remediation should be done with caution.

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Classic :smile:


Tasting was part of required training under @cyclopath’s tutelage. Never underestimate the power of organoleptics!


@spdking has suggested “salts” in at least one of the threads this has come up in. not sure where they would be coming from, as I’ve not run into them (some clown sprayed them on the weed?!?)…but I wouldn’t rule them out.

that’s probably not dissolving, more likely dispersing. sounds like fines +nucleated something. if it’s not going into ethanol it’s not target.

edit: that something is not sweet, so it’s not sugars…

not sure how many of the other threads you’ll hit with Search results for 'ethanol crystalls' - Future4200 but I suggest taking a look anyway.


I just noticed on the celite 545 (Supelco .02 - .1 mm ) package it says it contains free crystalline silicic Acid . When I search free silicic acid calcium salt comes up as though they are one in the same… I wonder if that stuff is making its way through ?

that would suggest washing rather than recirculating might be the appropriate response to me. I’ve not used Celite 545.



I am extracting thca primarily and the crude is not decarbed when it occurs

I wonder if maybe I should move away from the celite all together and try filter paper under the carbon instead?

I’m personally a fan of the T5/AC combo. Carbon alone likely won’t get you where you want to be.

Thanks for the suggestions! My filtration vessel is 8", do you have any suggestions as to where I might find 1um filter paper that large? I am looking but don’t see them.

Would be my approach. (USA lab has 22cm)

Others have used 1um felt from Duda diesel. And the trick of the trade thread has a tip on rolling that stuff to make a depth filter.

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A couple of other things I notice too is that the crude looks great( Nice colour and translucent) in the rotovap right up until the very end and then it very abruptly turns cloudy. It has a strangely sweet smell while decarbing and when ran in the short path has a very prominent blue head fraction that occurs at abnormally low vac.