A Theory on BHO/Rosin Decarboxylation with Natural Terpene Preservation

[Anonymouse]

Introduction:

Obviously, there are a number of ways to decarboxylate BHO/Rosin while preserving the natural terpene profile; this is just a simple method. There are numerous ways to expand upon this idea, which is why it has been published in this open forum. This SOP, if followed correctly, will produce +12kg of fully decarboxylated BHO in about an 8 hour shift, more or less. I indicated a 6" diameter vessel specifically for its’ higher pressure rating which should allow for safer operation. That being said, this SOP is entirely theoretical and has never been tested, to my knowledge.

A few science points:

• The vessels and spools are sized specifically so that they will not be more than 20% filled with BHO. This is by design; so that the pressure in the vessel should not reach critical levels at the designated temperatures.

• Always pull a complete vacuum, as deep as you can get, on the vessel before decarboxylating. This will speed up the entire process and remove most of the oxygen from the vessel to prevent any unwanted/uncontrolled organic reactions/oxydation.

• Tuf-Steel gaskets are expensive but are probably the best available material for this purpose. They have serious heat and chemical resistance, which is required for this process. They should also be torqued appropriately with a Torque Wrench (50in./lbs).

Abstract:

Cannabinoids, in their acidic form, will crystalize over time under normal atmospheric conditions and prevent a homogeneous solution from occuring. Also, the primary byproduct of acidic cannabinoid decarboxylation is CO2 gas, which distinctly affects the olfactor sensory organs; specifically, it has a numbing effect that deprives the user of a complete entourage experience and requires a higher temperature for vaporization. The CO2 gas may also deprive the user of oxygen during consumption, thereby affecting the overall experience.

The final process of degassing the oil will require much less energy as the butane/isobutane/propane-THC bond is much weaker than with THCA. As the BHO is now a mostly-homogeneous liquid, it may be easily degassed by any variety of thin film evaporation techniques. Further homogenization could require equipment not listed here.

Once the oil has been fully decarboxylated, degassed and homogenized, it wil vaporize at a consistent lower temperature and provide the consumer with a full entourage effect, unique to the extracted compounds. The subtleties of the terpene profile will be expressed with a degree of purity as true to the plant as possible, at low temps. Recommend 435-485F.

Considerations:

• Use teflon tape on your threaded fittings. If that isn’t enough of an explantion, please do not attempt this process!!!

• BE SAFE!!! I cannot stress this enough, heating volatile organic compounds ina pressurized vessel should only be performed under controlled conditions only by qualified individuals. If you question your qualifications, please do not attempt this process!!!

Safety Equipment:

• Eye Protection
• Chemical Resistant Gloves
• Chemical/Splash Resistant Lab Coat

Equipment List:

-x1 C1D1 or C1D2 working environment

• Booth, Hood or Explosion Proof Room

-x1 2-Stage Rotary Vacuum Pump

• with fitting and hose

-x1 Recirculating Heater/Chiller Bath

• Thermo Fisher Arctic A25 Refrigerated Circulator (AC150-A25)
  -25C - +150C, 12L, 115V/60Hz
• with appropriate thermal fluid in appropriate volume (+12L)

-x2 4-way Manifold (High temp threshold +100C)

• with fittings and tubing for Recirculator Connection

-x4 6"x8" Stainless Steel Tri-Clamp Jacketed Base

• with appropriate fittings and tubing for Manifold connection
• I would recommend quick-connect fittings rated for appropriate temperatures

-x4 6"x32" Stainless Steel Tri-Clamp Spool

-X8 6" Tuf-Steel Gasket

-x4 6" Tri-Clamp Vessel Cap w/ fittings

• Collection Pot or Diamond Miner Lid
  -Fittings:
  -Port with Ball-Valve
  -with fitting for vacuum hose
  -Pressure Relief Valve (200psi)
  -Compound Gauge (-30"Hg - 250psi)
  -Max temp +110C!!! (very important)

-x8 6" Tri-Clamp High Pressure Clamp

Preparation:

1. Connect the Recirculator inlet and outlet each to a 4-way manifold.

2. Plumb each 4-way Manifold into the Explosion Proof Environment.

3. Ensure adequate clearance in the Explosion Proof Environment for the height of the decarb unit (approximately 48").

4. Connect each Jacketed Base to each inlet and outlet manifold.

5. Fill the Recirculator resevoir with 12L thermal fluid.
   a. Begin circulating fluid.
   b. Top off resevior as fluid fills Jacketed Bases.
   c. Stop circulating fluid, disconnect bases.

Process:

1. Fill each Jacketed Base with 3-3.5kg degassed BHO.
   a. Ideally, 1500ppm or less residual solvent content.
2. Assemble each unit by attaching:
   a. 6"x32" Spool with Tuf-Steel gasket and High-Pressure clamp.
   b. 6" Vessel Cap with Tuf-Steel gasket and High-Pressure clamp.
   c. Using a Torque Wrench, secure each clamp with 50in./lbs torque.
3. Place each unit in the Explosion Proof Environment.
   a. Connect each Jacketed Base to the appropriate inlet and outlet hose from the manifold.
   b. Set the Recirculator temp to 15C.
   c. Start circulating thermal fluid.
4. Connect the vacuum pump hose to the Decarb Vessel.
   a. Turn on the Vacuum Pump.
   b. Open the ball-valve.
   c. Once maximum vacuum depth is achieved, close the ball-valve and turn off the pump.
   d. Disconnect vacuum pump hose.
5. Set Recirculator temperature to 110C.
   a. Monitor the pressure in each vessel as the temperature ramps up, if the pressure begins to approach 200psi:

• Adjust the Recirculator temperature to 15C and allow the pressure to drop.

  • Once the temperature has arrived at 15C, allow to circulate for 30 minutes.
  • Open the ball-valve to vent excess CO2 gas to 0psi, close the valve.

  b. Once the Recirculator arrives at the set temperature:

  • Allow 110-150 minutes for the decarboxylation process.
  • The vessel pressure should not exceed 150psi.

6. After 110-150 minutes at 110C, set the Recirculator temperature to 15C and allow to cool.
   a. The material should be completely decarboxylated.
   b. Once cool, open each ball-valve to vent any remaining CO2 gas.
   c. Close each ball-valve.
7. Attach the Vacuum Pump Hose to each miner, respectively.
   a. Pull a full vacuum on each Decarb Vessel.
   b. Allow to sit for 2 hours under full vacuum.
8. After 2 hours under vacuum, open the ball-valves on each miner.
   a. Set the Recirculator temperature to 35C, start circulating thermal fluid.
   b. Disassemble each vessel.
   c. Once the decarbed oil is at temp (35C):

• Disconnect vessel from manifold
• Open ball-valve and remove cap.
• Transfer to Ball/Mason/Kerr jar for storage.

Summary:

The primary byproduct of decarboxylation is CO2 gas, which is problematic when attempting to decarboxylate BHO in a closed vessel. By placing the material indended for decarboxylation in a pressure rated vessel and creating a vacuum environment, the material may be fully decarboxylated while preserving the natural terpene profile due to the available headspace and oxygen-deprived environment. The additional pressure created by the CO2 gas will allow any volitalized terpenoid compunds to reflux under pressure while cooling, thus allowing the preservation of the unique terpene profile. Once processed, vacuum boiling of dissolved CO2 gas in the oil should aid in the degassing of any residual hydrocarbon solvent.

The Recirculator should cost about $6k, brand new, and each decarb vessel shouldn’t run over $1.5k. All told, so long as you have a C1D1 or C1D2 environment available, this setup should cost about $12-$15k to yield +12kg ready to consume product per 8-hour shift. This is potentially the highest margin product in your inventory, right now.

[Akoyeh]

Great write-up. Thank you for sharing!

Are you looking to achieve complete or partial decarb with this process? Personal experience working at this scale leads me to believe that it will take longer than you anticipate, but you’ve given me some ideas that I think could be implemented to improve upon what we’re currently doing. Going to see about putting some of them into play tomorrow.

[moveweight]

XD so clean on the write up. I am still processing.

My only questions so far: what benefits do you think doing this vs separation / reintroduction methods to not have terpenes during decarb (at all) are?

Have you done terp testing on finished product comparisons? Sounds fun to give a whirl.

[Anonymouse]

The main principle here is to maintain a nearly unadulterated terpene profile. In principle, you should be able to fully decarb each batch with 110C heat for 110 minutes. As decarboxylation occurs, the CO2 gas by-product will begin fill and pressurize the headspace in the vessel, slowing down the decarb. I’m not going to attempt the Thermo math to determine the required wattage to decarb the THCA , there are so many variables to account for. A higher wattage recirculator would speed things up for sure.

[Anonymouse]

Deconstructing and reconstructing BHO, mechanically, tends to degrade the product, IMO. It seems to offer the opportunity for even the slightest oxidation of the terpenes and I’ve noticed the THC seems to help stabilize the solution. To be fair, I am not really impressed with the quality of the final product yielded from that spinning and reintroducing process. I think this method yields a product that offers the experience of a true expression of the full cannabinoid/terpenoid profile. This process will work well regardless of the initial terpene content and you don’t risk losing those heavy, sticky terps when you decarb your diamonds.

If you want to separate or isolate your terps just distill them, it’s the 21st century! Maybe I’ll post that next week, a SOP for strain specific distillate with water clear terpenes. That is also a product that has huge crowd appeal.

[Kingofthekush420]

@Anonymouse

As decarboxylation occurs, the CO2 gas by-product will begin fill and pressurize the headspace in the vessel, slowing down the decarb

Pretty sure most of us here have come to the conclusion that pressure / vacuum isn’t going to effect decarb time since decarbing is a process driven by energy. You’d need very high pressures to prevent that bond from wanting to break from what I’ve heard

Decarboxylation under Vacuum?

From this paper, my read is that the vacuum doesn’t substantially affect the decarb time. There are time/temp graphs about half way through. They look not dissimilar to ones from non-vacuum processes. I’m not a chemist, but my understanding of decarboxylation is that we’re basically dumping enough energy into the material to beak the bond between the carboxyl and the cannabinoid. I think that means that the primary determinant will be the heat energy applied to the material, not the pressure …

[cyclopath]

@Anonymouse

Always pull a complete vacuum, as deep as you can get, on the vessel before decarboxylating. This will speed up the entire process

How?!?

Pulling less vac, backfilling with N2, then vac’ing again will get the O2 without so many of your terpenes

[Anonymouse]

In a closed vessel, the decarb action will require more energy input over time because the pressure created in the headspace by decarboxylated CO2 gas. I also think the solution will become saturated with dissolved CO2 gas (carbonation) during the process. So, as decarb begins, the CO2 gas fills the head space in a semi controlled process with a fixed amount of energy input. As the pressure increases it should require more energy for the new CO2 gas molecules to percolate through the solution to occupy that head space. I think the solution will hold a certain amount of dissolved CO2 gas under heat and pressure, which may also slow the decarb process.

If the energy input is fixed, time should be the affected variable as the conditions change. Also, without insulation, heat loss will affect the energy input. Maybe someone smarter than me will chime in with a real explanation.

[cyclopath]

As far as an SOP goes, this is well written and touches on all the important stuff. Great job. I’m curious what you’ve convinced @Akoyeh to change because I’ve certainly suggested some of the same things.

I just don’t believe you’ve got the “Vac will speed decarb” bit correct.

TYou said you haven’t done this?

So where have you seen ANY indication to support your assertion that vacuum will speed decarb?

What pressure do you start to see decarb slow? Or do you simply not see the evolution of CO2 at higher pressures because it remains in the liquid phase?

Removing the O2 is a good thing…

Solid data showing 150psi slows decarb by even 5% would surprise me. I don’t have the vessels or prv on hand to gather that data. Anyone else?!?

[anon64373531]

The rate of decarboxylation is independent of pressure. A point that’s theoretically tripped me up on occasion.

[cyclopath]

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5549281/pdf/can.2016.0020.pdf

Math isn’t my strongest suit, but I don’t see the concentration of CO2 listed above, do you have math to show how increasing pressure will change the rate constant at any given temp?

PV =nRT implies to me that an increase in pressure can be looked at as a proportional increase in temp (holding n,R & V constant).

Which should speed rather than retard the process…no?!?

[G_Boe]

I would not expect this method to yield better results than spinning off terpenes from crystalline THCA or by distilling off the terpenes. I say this because I have done exactly what this SOP calls for, and the result, even after being careful to have all oxygen removed, still smells degraded and different than the starting material. In my experience, the terpene profile begins to smell sour and almost rancid.

Spinning off the terps allows them to be separated without increasing the temperature much, as the temp increases from spinning, the terps should become less viscous and spin off more easily. This process adds much much less heat than the one outlined above.

Distilling off the terps under vacuum allows for the terps to “escape” the heat source once they have enough energy.

Your process is holding the terps in a high temp environment for longer periods of time than the other two processes. I can just say first hand the quality of the terps goes down dramatically.

Also, decarbing under pressure should increase the rate of decarb, not reduce, as mentioned above.

[ShuckleBerryFinn]

Sounds a lot like Harvest Direct’s LACY method

[406_Chemabis]

@Anonymouse

In a closed vessel, the decarb action will require more energy input over time because the pressure created in the headspace by decarboxylated CO2 gas. I also think the solution will become saturated with dissolved CO2 gas (carbonation) during the process. So, as decarb begins, the CO2 gas fills the head space in a semi controlled process with a fixed amount of energy input. As the pressure increases it should require more energy for the new CO2 gas molecules to percolate through the solution to occupy that head space. I think the solution will hold a certain amount of dissolved CO2 gas under heat and pressure, which may also slow the decarb process.

I ran into this logic too a few times, however, it is the surface area of your input material that is affecting the rate of decarboxylation. Think of it as every molecule of THCa getting the same exposure to the applied energy.

Pressure most certainly plays a role in chemical kinetics with respect to GASES ONLY. Hence why we do not want any oxygen in the closed system during this process. Inert or inert behaving gases such as N2, CO2, Helium introduced into your headspace will help with this.

Keep in mind, even with a full vac pulled on the system, once heat is applied, can have unwanted side reactions with the terpenes (even without oxygen being present if sufficient heat and pressure are present).

Best way to decarb live resin

I go ~18-24hrs. Most of that we are at home. no need to watch it boil. Set it up and leave. Done in the morning… We can decarb up to 40kg at a time. Run right around 100C

@cyclopath and other fellows have gone 100C and also lower in temperatures such as 80C which in my opinion goes a long way for the final integrity of the product.

[Dannywarbucks]

logically I feel most terps would not vaporize in significant amounts in an elevated pressure environment such as during a pressurized decarb.

[CuriousChemist22]

Terpenes of course would do better under pressure, but you do risk creating a reactive environment. The method least likely to alter your profile is simply to remove the hte ahead of time, decarb your cannabinoids, utilizing increased heat transference to increase the rate of decarboxylation(deep unagitated pools take longer), then reintroduce your hte. Good hte spins off clean without any heat, and if the vessel it is separated in is backfilled with inert atmosphere you can prevent any oxidation.

[406_Chemabis]

@CuriousChemist22

The method least likely to alter your profile is simply to remove the hte ahead of time, decarb your cannabinoids, utilizing increased heat transference to increase the rate of decarboxylation(deep unagitated pools take longer), then reintroduce your hte.

As someone that used to do this a lot with CO2 extracted material, which final product integrity would you (and everyone else for that matter) consider the best representation of the plant?!…

Fractionating the HTE from the Cannabinoids, decarbing, then reintroducing

Or

Decarbing under pressure

A Pepsi / Coke challenge would be quite interesting given all variables are kept the same such as input strain material/rosin/resin, etc

[Dannywarbucks]

Spinning off hte at scale is anything but simple.

There’s also no way there isn’t significant THCa still in the hte, which can also be problematic.

[anon64373531]

I would think throwing conjugated organics in a high pressure environment would increase unwanted reactions through collision alone.

[Dannywarbucks]

Probably. I guess the question is, how much of that actually happens?