Identification and Separation of hydrophilic emulsions in crude extract

Hello all,

Does anyone have any solid experience with identifying and separating any hydrophilic emulsions in crude extracts?

We have been experimenting with liquid-liquid techniques for removing hydrophilic compounds, only thing is we don’t really know what it is we are pulling out and what the best system for separation would be.

We have noticed a reduction in vapor pressure fluctuation in what I believe are correlated to reduction in lighter volatiles on initial distillation of crude.

Any experience or ideas?


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Interested in your liquid-liquid techniques. We are dealing with some CBD hemp crude that is just clogging up every filter we have, even after super cold winterizations. My only conclusion is that it is all just hydrophillic dirt/silt/sediment/clay that contaminated the biomass and was small enough to pass into the crude extract.

I can hear @Photon_noir’s brain exploding from here…

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LOL! :joy: @SoStupendous Not exploding, but very funny, nonetheless! This is actually a new way of framing the question, so I don’t mind. :blush:

@Phytoalchemy I have lots of experience and ideas, but I think I would need a more thorough explanation of your process, including solvents used for extraction, Winterization, degumming, your pH if adjusted, etc. to give you a good answer. Does the aqueous phase discolor pink, brown, dark gold, or any other color upon sitting in open air after a while?

@distillat3r All the dirt and plant sediments should be filtered out during your Winterization, if not while draining your extract or otherwise filtering prior to Winterization. Anything clogging your filters after that could be the resin itself if too concentrated, or something that was previously dissolved and is somehow precipitating after all that processing. Like with the person above, I would need more details of your process to give you a better answer.


Thanks for the input. After the 2nd winterization, nothing was falling out no matter how cold. It was cold ethanol extracted to begin with, and we usually have little to nothing to winterize out from the crude extraction team that this was source from. But this was just an example of terrible hemp biomass input material. Even after the 3rd and 4th winterization, my stage 1 and 2 filter papers were still clogging like crazy. My determination is that it is a fine clay silt that contaminated the input material. Instead of wasting more filter paper, we just discovered (like 30 mins ago, LOL) that we need to filter it through the silica bed before we do anything. It is basically 15-20% clay from what we are pulling out. The fine silt kept breaking down further and getting through subsequent filter paper layers. But I think we go it!


Hah, sounds like dirt. I ended up with some literal “dirt weed” trim once. Kept getting to the bottom of the barrels and realizing what I thought was kief was actual DIRT. It was a delivery of about 500 lbs or so and I’m pretty sure it might have just been piling up on the ground at a farm and they shoveled into bags haha. I hated that fucking trim. We had 150psi bag filters though, so less of a bother.


Yea this is def clay matter that passed through the crude extractor’s 1um filter. It is the super fine adobe clay mud we have out here. Well today sucked, LOL.

Wow. That is a very unusual issue! Yes, definitely use a 3D filter matrix like cotton and/or silica for bulk fines like that. Flat paper will get you nowhere, as you have found. How odd. I have seen that kind of awful with straight kief, but not from herb!


You might even consider centrifuge.


We have done plenty of kief soaks and filtrations and they are a breeze in comparison. This hemp must of literally been dragged in the mud. Funny actually, we left a bucket of the suspension on the table next to a running vac pump, and the vibration of the table after 1 hour or so caused some of the fine clay particles to fall out! We talked about building a vibration table with a concrete mixer pump to see if we could settle it out, also discussed a cetrifuge. Looks like the silica bed got it all though!


they ran out of DE and filtered it through local dirt for you instead :slight_smile:


Mixing/settling tanks are very common in most industries.

Are you attempting to winterize your cold etoh extract prior to recovering any solvent? I’ve found that past 20:1 etoh:oleoresin no matter how long/cold the solution is, lipids are so far from saturation they refuse to precipitate.


Excellent! That is good to hear! That must have been some super fine ball clay to get through your filters like that.

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Would a sock filter work for the clay particulate?

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Im glad to see the use of the words oleo/resin is finally getting into the consciousness. What I’m guessing they have going on here is Slaking. Shadow and i played with some same clays a year or two ago now any H20 and its done.

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Currently the rough SOP is as follows:

  1. EtOH Extraction using cryo-chilled EtOH → Crude
  2. Winterization of crude in EtOH 10:1 for 24hrs at -78*C in deep freezer
  3. Wax filtration
  4. Liquid-Liquid wash with 2:1 RO H2O:Crude using a vortex to breakup emulsions
  5. Centrifuge @ 8000 RPM
  6. Pour off “milky water” and make a 1:1 Fresh RO H2O:Crude solution with remaining material.
  7. Vortex
    8.Centrifuge at 8000 RPM
  8. Pour off clean water
  9. Heat remaining extract and removing from centrifuge bottles.

At the moment its a small scale sample prep experiment, only processing maybe 2 or 3 kilos to see how they behave.

Any remaining H20 and terpenes are removed during a low-vacuum light volatile strip then head to SPD for final distillations.

We haven’t checked the pH. The aqueous phase is an opaque “light coffee” color.

Thank you for all the replies!

(Edited for clarity)


In case the implication is not clear, the crude extract is still in the EtOH solution and filtered when the ROH2O is being added.

…and has precipitated out by the second rinse because all the ethanol is gone?

Correct if I’m understanding you right, that second rinse is mostly to clear out any more of the milky aqueous phase and we have been left with a fairly viscous extract that just needs light-volatile stripping and decarboxylation.

Hope I’m painting the right picture

Interesting approach using louching (making the milky microemulsion of resin globules in ethanol with excess water beyond the azeotrope). Are you using the centrifuge to break the emulsion and form a layer of resin separate from the ethanol? I usually just partition the aqueous ethanol with a non-polar solvent, which causes migration of the “milk” (the microscopic resin globules) into the non-polar, leaving the lower watery ethanol transparent, albeit somewhat colored. Your method sounds like it keeps more of the color components in the aqueous phase, though!