HELP! Unknown Substance In Crude

Hey guys! I am a long time reader, but this is my first post. I am having trouble with a tar-like substance in my crude. I am currently extracting hemp with 200 proof ethanol at 0C and removing all the unwanteds through filtration. My potency is running between 65-70% CBD even with this tar in my crude. I am not selling it with any of this substance in my oil as it will mess equipment up when distilling it.

Things I have found out about it so far:
Miscible in ethanol, but immiscible in heptane.
Can extract it from the biomass no matter what temperature I extract at. I have gone all the way down to -80C and as high at room temperature.
I have narrowed it down to my biomass or ethanol. I don’t know why it would be my ethanol, but I have been surprised before.
I have also changed biomass to a different lot and still pulled it out. I pulled 14.5g out a 50g sample in the original bio and 1.5g out of the newer bio.

I am really hoping someone has answers. I have tried a lot of different things to remove it. Only solution I have come up with is needing to put all my oil in heptane to remove it.


Sounds like sugar


These are sugars bud. Seen it many times especially at scale. Extracting cold is not gonna cut it. You need to winterize/filter properly. I would suggest a membrane skid.


Its not sugars…I have made clean crude with this method. It doesn’t like water either.

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Looks like either sugar or gums (which are mostly precipitated phospholipids). Extracting cold definitely helps to some extent. There is a certain extraction temperature that makes sense to extract at which will pick up minimal gums, not destroy your extraction yields, and not completely wreck your distillation equipment. What temperature is worth it? that is really up to you


Well you could submit some to a lab for some quick LC/MS or GC/MS analysis and then have them do a peak scan and compare the peaks to a known library.

This is really not the most ideal way to perform identification of an unknown substance but seeing as it is most likely some form of phosopholipid, sulfolipid, sugar, or other plant gum or wax, it would probably be pretty easy to determine to some degree of accuracy what you’re looking at.

I would agree with most other people here suggesting sugars or plant gums of some sort.


I’ve seen this from time to time.

Have you checked your proof? You said 200, but are you sure?
Does your miscella go through temp swings? In other words, does it go from cold to room temp before filtration? If so, are there any fines in the miscella that continue to extract when these temp swings occur?
It looks like sugars and being miscible in etoh and immiscible in heptane makes me lean towards it being sugars.


I have checked the proof of my ethanol before I start extracting, in the middle of my process, and after recovery. I have never been below 195 proof.

I didn’t have temperature swings either because I have extracted this “tar” at cold temperature and at -80C. I have even taken it so far as to hand extract at both of these temperatures to ensure I hold temperature through extraction and filtration. It still showed up in my crude.

If it was sugar or gums I wouldn’t have seen it in my -80C extraction.

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Some proteins don’t dissolve in water and dissolve partially in alcohols. How do you prepare your biomass for extraction?

Biomass is kept in our warehouse and goes in a grinder at room temperature. Nothing to special is done to it before extraction.

If you know the gums do not dissolve in heptane then you have your solution for selling the batches that are coming out this way. Redissolve in heptane, filter, evaporate, sell.



That is my last resort option because I don’t have any ventilation for large scale heptane. I am trying to find a solution that works in ethanol before I have to go that route.

Could you use denatured? At 5% heptane you would need the same ventilation requirements as with etoh no?
When we would see that gum/sugar it was usually with etoh lower than 180 proof or reclaimed etoh that had carryover in it and it was warmer than -30C.

That’s sugars

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“If it was sugar or gums I wouldn’t have seen it in my -80C extraction” is 100% false.

-80C extraction helps reduce the amount of sugars you extract but it does not remove them completely. I have been extracting for the past year and a half at -80C and it only took me the first 2 months of starting to realize even at that temperature you HAVE to still water wash or filter through a membrane to remove the sugars.

I completely destroyed my wipers because of sugar buildup prior to me implementing a water washing stage.


Looks like sugars to me. Submit a sample to a laboratory to confirm. They should be able to do GC/MS or LC/MS to get you an exact sugar.

You’re doing most of the things you should do to reduce the problem. The real problem is that you’re extracting a botanical. The amounts of these sugars you’d find very from plant to plant, genetics to genetics. You could test the biomass prior to purchase or tolling and figure out how sugar laden it is, but that’s expensive and time consuming. How would you go about processing the material if you KNEW it had sugars?

I have seen this exact gunk show up recently when running vapor static oil. It is not “sugar” as it doesn’t dissolve in water. It may bear some resemblance to what people are CALLING sugars, only because they aren’t really doing analysis to find out what it actually is.

I don’t think it’s proteins either as a 1000 Da UF membrane fails to remove it in ethanol.

No, I don’t really know what it is, either. I have some samples out to KCA now to see if they can analyse it.

Sugar seems to make the most sense (though not necessarily accurate) because as you heat it above 160 you start to notice a kind of tar building up, a loss of pressure and what looks like water in your still. I deduced this was sugar dehydrating and degrading and after a water wash, this was midigated, but even still there was a residue remaining.

It could be a class of glycolipids as that would have modest solubility in ethanol and still tar up like that. Is the residue water soluble? I found that was the case for the tar in my boiling flask.

Did I miss what type of filtration is going on here?

We did some R&D on silage chopped, whole plant, biomass. We extract from-40 to -20 C. Once the filtration was dialed in, we could run 65+ % crude with the whole plant and through our distillation equipment.

What did we learn? Paying for filtering that shit was stupid. It took a lot of time and effort to figure out what we already knew. And, that with proper filtration, you can run some shitty material and get a desired result.

Once that shit show was done, all our filtration was in place and we feel confident running proper biomass from start to finish with zero issues for almost 3 years now.