Thanks for sharing! We also use something similar to that style chamber. We do the whole extraction together and don’t separate.
We pull a vac and back fill with nitrogen twice prior to applying heat to the chamber. This will reduce/prevent terp degradation and oxidation. Currently we run at 107c until we hit our target PSI. We arrive at that target number by estimating the amount of THCA (70% is our usual assumption in the equation) in the extract and calculating how much CO2 that will be released upon full decarb. Then we apply that volume of CO2 to the volume of the vessel to arrive at our target pressure. This isn’t terribly precise, but it definitely gets you in the ballpark and allows you to know when decarb creeps to a near halt. We generally stop heating once pressure stops creeping more than 0.5psi/30min.
We always leave just a touch of THCA behind, which is great because that’s a decent marker that it isn’t distillate. Residual THCA only seems to become problematic when it is above 5%. And by problematic, I mean decarb continues when oil is re-heated for filling and generates bubbles that screw up filling.
As long as vessel is cooled prior to releasing pressure, any vapor state terps should re-condense. We allow the vessel to cool to 40C prior to releasing pressure. Terp content as a percentage of the oil SHOULD be higher than when you started pending there were no leaks and cool down was allowed to happen. Total weight loss should be 9-10% depending on THCA content, of course.
The oil will need to be “flattened” as well, due to the entrained CO2 still present, but that’s usually accomplished with a quick trip to the vac oven for a gentle purge until you see the carbonation dissipate.
Total process time for 2-2500g is 8 hours give or take.
It goes in a 50C oven right after pouring from decarb. Takes 30-60 minutes at -22 to -29 depending on the size of the batch and CO2 entrainment. We normally stop the purge if we see frequent large bubbles escaping, as those are thought to be terps. CO2 will generally be small bubbles and come out rather quickly and easily.
There’s no need to put it in the oven you can just put it in a pot of hot oil with a thermometer in it in order to have temperature control. Also I would use Argan instead of Nitrogen and probably wouldn’t pressurize it the same way you do.
Edit: only after posting my reply my device showed me they were 144 replies to the original post. My reply pertains only to the original post.
As far as winterizing it with minimal terp loss, you can winterize in propane (low boiling temp and thus much easier to purge at lower temperature)
Long time lurker here. I finally had to make an account so I could follow up on this. Has anyone been able to continue testing closed vessel with inert atmosphere decarboxylation and been able to get coa’s for comparison?
We are currently looking at different methods of getting our BHO into cartridges and I’ve fallen down this rabbit hole of how to do this without absolutely destroying the terps. With our fresh frozen material, we have been playing around with separating the terps and THCa via diamond miners, melting the diamonds, decarbing, and then re-adding the terp fraction back into the mix (the carts are incredible); however, we continue to have poor separation and the final product is returning with 10%-25% THCa which then leads to an abundance of sugaring once it makes its way into the cartridges. My only lead is that our separation of THCa and terps is insufficient leading to a large concentration of THCa sneaking in with the terp fraction. Long story short, the physical separation via diamond miners has been less than efficient/scalable.
With that being said, we have begun to take a look at utilizing our bulk BHO alongside decarboxylation to get it into cartridges, but our concern is that this will produce dooky carts due to oxidation and terp loss. Based on this thread it seems like people have had success in getting this to work in producing solid BHO carts. Does anyone have any COA’s or anything that could point to a larger amount of terpene preservation - or has this been mostly antidotal based on flavor ect (which I will absolutely take as well).
you can prevent oxidation by doing the decarb in a nitrogen atmosphere. You can reduce (not eliminate) terp loss by doing the decarb at as low of a temperature as possible. This doesn’t require any equipment that can withstand high pressures. In my experience, you can make fire BHO carts using these techniques.
If you want to decarb under pressure, you’ll be looking at significant $s in equipment. Simply because there will be so much pressure built up by CO2 that your equipment will need to be registered pressure vessels (I could be wrong here).
As long as you do your math correctly, it’s reasonably easy to get off the shelf components in 6" or smaller diameter that will handle the pressure easily and accomplish complete decarb under pressure with no terp loss.
Math is the key, though. And PRVs, just in case your math is wrong.