THC degradation after distillation

Hey guys, I hope to find some answers with your help. As the subject says I’m having a problem with my THC content decreasing from 70% to 45-50% after distillation process.

I start baking my biomass in an oven for 3 hours at 240F and then immediately put into a supercritical CO2 extraction then goes winterization, filtration, evaporation, decarbing on a hot plate (110 mins at 110C). At that point the potency test result is at or around 70% d9-THC and around 7% CBC (d10). After distillation the numbers change to 45-50% d9-THC and 20-25% CBC (d10) which I’ve been getting constantly time after time.

I’ve tried to find the problem within the distillation process and tried many different approaches to no avail. My rig is Lab Society’s 5L Gen2. During my last distillation I tried to keep the temps as low as possible and distilled 200g at 177C in BF and at around 155C at heads in 3 hours. My vacuum was at 100-150 microns throughout the whole process.

I had a chance to speak with Bryan from Lab Society and was told that the problem comes all the way from the extraction process/extraction type. The CO2 is getting mixed with water that’s in the biomass/extractor’s system under high pressure and forming carbonic acid which gets carried over all the way into distillation process and that acid + heat degrades the THC. I was advised to wash the decarbed oil with baking soda which will neutralize the acid and bring the pH level to neutral.

Since I’ve never done the washing with water I would highly appreciate any help or info of step by step process explanation to accomplish this task if the theory with the carbonic acid is actually true.

Thanks in advance guys!!!

This is a quote from this post: I make terrible distillate....why?
It’s got everything you need for distillate. (I don’t know why the quotes not working right.)
pro[quote=“Distillforeal, post:16, topic:6650, full:true”]
Take your first pass smelly crap dissolve in heptane 3:1. Mix up a shit tone of water and wash in with diffrent ph water from 4-10 some say make the water saltly idk you tell me what works better. Occasonally put metal work prob into top of sep funnel to get probe wet with heptane solution wait to dry smell if residue is gone. After last wash drain solution and run threw magsil pr or is on a budget maybe just silica? Then distill. Again smell gone. If you dont have enough first pass around downsize boiling flask one size could work?

Why do you bake your biomass in the beginning and then Decarb your oil at the end? I have never used a CO2 extractor so I am not well versed in exactly how it all works. I think you’re supposed to decarb before extraction which means decarbing after would be pointless. This could be where you’re degrading your product. Also, baking your biomass for 3 hours at 240F seems like over kill and a big waste of time in my opinion. There are decarb charts on the interwebs that will show you time and temp for decarb. If you want to stick to 240F the total time your flower should stay in the oven is right around 30 minutes. You could let it go a little longer if you want to stay on the safe side. Is there a reason you do it for 3 hours?

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Hey @CannabinoidChemist, the main reason for baking before the extraction is to get read of any water in the biomass as the CO2 etractors don’t like water inside them. And secondly of course the decarbing process. And the reason for the secondary decarbing on a hot plate is to remove any residual solvents (ethanol), water and terps as much as possible before the distillation.

Okay I’m sorry I misunderstood the procedure the way you laid it out the first time. I think the baking of the bud in the beginning is not a bad way to remove the water but I would probably try and set up a dry room maybe that will help with degradation. As for removal of EtOH on the back end I would try to get a rotovap or FFE to get that ethanol off faster. As for the acidity issue you maybe experiencing I’m not to sure how to combat that issue but I know I have seen tid bits all around the site where you could find how to alter ph in an effort not to make side products during distillation. I actually might look this up for myself so that I’m not so ignorant to the subject.

@CannabinoidChemist, no worries and thanks for the replies. I use dehumidifiers in the extraction room but I guess it’s still not good enough and some moisture is still getting in to the extractor’s system and creates carbonic acid.

I do run the oil through the roto-vap after filtration. I do the decarbing on a hot plate to get rid of the very last bit of ethanol, water and some of the light terps, which will make the distillation to go a little bit smoother.

Hmmm. Well do you have a smaller room that you could put hanging racks up in? With a smaller space you could get that humidity and temp down to a more ideal range to do some passive drying and then finish up in the ovens. Instead of hotplates maybe you could use a vac oven to get that ethanol off with a more gentle heat. Just some ideas to think about and play around with. The more thin the layer of extract in your vac oven the faster you’ll be able to get that ethanol off. So you might need some pretty big pyrex trays stacked up on shelves depending on your through put in the facility.

Have you tested the ph of your extract? Do you have a GC that you could do in-house testing with to identify the carbonic acid? If not maybe send it to a third party lab and see what they can tell you about your extract to mayne give you a little more insight.

While I am not a CO2 extractor and have very limited knowledge in that arena, I do know that non-acidic cannabinoids (decarbed) extract better with C02. I believe that many who extract with it decarb before extracting for that explicit purpose. Unless they’re doing a terp run on it first, which I do not believe the OP is doing, it increases efficiency.

@greenXlabs, if you told Byran that you decarb/desiccate for 3 hours @240F and go right to extracting (and I know you are in a pretty dry climate), he doesn’t know what the hell he is talking about. The likelihood of water in your processes being the problem is so minute that it is ridiculous (yes, literally deserving ridicule) to claim as the primary suspect.

I have poured countless pounds of dry ice directly into tincture (effectively carbonating it) and not had isomerization issues that bad. From what I can tell, you are overcooking your cannabinoids. Oxygen plus heat multiplied by time equals a recipe for isomerizing.

Have you pH tested your solvents and extracts at all? Before I get too high on my horse here, I should probably actually make sure you know whether your crude is acidic. Haha. Wouldn’t I feel stupid if it was. Haha.

Like I mentioned to you the other day, I think we need to get your SPD process (and some other stuff) updated a bit. Your roto is more than sufficient for removing all the solvent post-winterization. While devol may be good for reducing volitiles, based on how much the cannabinoids have already been cooked, you may want to include devol right into your SPD process.

I can also tell you that no matter how many hours you work to strip the heads, they never fully go away. 3 hours is too long, and you are again unnecessarily frying cannabinoids. Also, distilation should not just be conducted at only 2 temps (not sure if that is exactly what you’re doing, but it seems like it). Distillation temps should be graduated and staged relative to vacuum levels and vapor temp.

For you, I would suggest starting at 100C and make 10 degree bumps when the vacuum level drops back down and the head temp has begun to drop. Once you see mains coming through, switch to 5 degree bumps and watch it the process. Run slow the first few times and take notes about every parameter and time metric you can. Use that as a baseline, and move to speed it up from there.

Again, I am almost completely certain that water has nothing to do with this.


@ExTek90 did you solve this?

Sort of, different people/machines are doing different, but, similar things to induce this phenomenon.

Seems like for the most part it has to do with water content in the biomass interacting with the highly pressurized, potentially dirty, CO2.

Separate collection vessels and proper extraction parameters are vital if one wants to avoid unnecessary cleanup steps afterwards.

You need to distill hotter. At least for the first pass. The condenser temperature throughout the distillation will also determine if you’re “Hot condensing” off undesirables. Your head temp should also be much closer to your solution temperature to indicate mains.

@ExTek90 “Dirty” CO2.

From repeated use or right out of the cylinder?

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Both things can be an issue.

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Just pull the water out of the oil after extraction and adding step in the flask during distillation takes care of decarb

this reads like you’re picking up acid/salt somewhere along the way.

you shouldnt have that much d10.

idk much about the cultivation side of things but i know some things people put on the plants can lead to isomerization down the road.
the next most likely thing to me would be in your filtration process, from clays or AC or something?