12. Refinement
(Troy works on cleaning up the oil in 2016, Port Townsend, WA.)
What separates two people most profoundly is a different sense and degree of cleanliness.
Whether you’re using CO2 or a chemical process for extraction, the first product you’re likely to get is probably going to be somewhat similar- a waxy, sticky, goop, sand, or crumble that you can do one of the following things with:
You can choose to purge your wax in a vacuum oven, which means evaporating the chemical solvents and moisture out of the extracts.
A vacuum oven is a special oven that uses a vacuum pump, best used in conjunction with a ‘cold trap’, and, well… heat.
The purpose of the vacuum in the extraction and refinement processes is that it allows you to artificially lower the boiling point of a molecule, enabling you to vaporize that molecule at a boiling point lower than the temperature that would normally cause that molecule to degrade.
For instance, the normal boiling point for the THC molecule is 314 degrees Fahrenheit, which is well past the range at which THC will start to degrade under prolonged exposure to this heat.
A vacuum must be employed to induce the THC to vaporize at a lower temperature, that won’t degrade its chemical structure.
A strong vacuum used in combination with a long path column, not only reduces degradation as stated above but also serves to better isolate compounds during distillation. This is really nerdy stuff having to do with reflux that we don’t need to cover here, just know it can be done, and fairly easily with a little training.
As you may be picking up on, there’s a pattern developing in these processes, requiring more selectivity during your refinement will often result in longer refinement times.
At this point, if you need to take a break to smoke a bowl, and contemplate the mysteries of the universe, it would be entirely understandable. Getting a quick physics degree wouldn’t hurt either.
Most vacuum-pump-based systems also have what’s called a ‘cold-trap’. This is basically a chilled section along the vacuum line, which inevitably draws vapor. The cold trap cools the vapor as it passes, before getting to the pump. This condenses any volatiles back into a liquid state, which can then fall out of the airflow and down into a ‘trap’. This protects your expensive, mission-critical pump from wear caused by vapors passing through the pump and degrading parts as they pass through.
Once your waxes or other crude extracts are free from chemical and water residue, then these products are theoretically salable and can be evaluated for quality control.
If your goal is making a consumable or vaporizable oil though, you don’t want to stop there.
Instead of a vacuum oven, you’re going to want to ‘winterize’ your crude extract instead and then purge the solvent out later with a rotary or thin-film evaporator.
And no, just in case you were going to ask, ‘winterization’ doesn’t have anything to do with getting high while snowboarding.
Winterization
I poured spot remover on my dog. Now he's gone.
Winterization is a process that is used to separate your essential cannabinoid oils from the waxes, fats, and lipids in the plant material. To do this, you soak your extract in ethanol and freeze it for 24-72 hours – ideally in a cryogenic freezer. This results in a slurry of cannabinoid-infused alcohol with blobs of oil suspended in it, resembling a lava lamp that is still stuck in the ’70s.
When it’s ready, the ‘slurry’ of frozen ethanol with cannabis wax material is filtered through paper and a Buchner funnel into a flask. This is just a glass or ceramic funnel that has a large volume collection vessel at the top.
Hint: for better oil clarity, try filtering it more than once and through, adsorbents. You will thank us later.
Now that you have removed the wax from the cannabinoid-infused alcohol…how do you get rid of the alcohol? You use a really complicated but cool-looking chemistry apparatus called a rotary evaporator, or roto-vap for short.
Unlike a vacuum oven, a roto-vap uses a combination of heat and vacuum along with gentle agitation and thinning to vaporize off and capture solvents. Through this combination of parameters, the rotary evaporator typically does a better job at isolating and controlling the evaporation points of different targeted compounds, than the vacuum oven. However, it works best with winterized, or dewaxed, oil.
This can also be explained as the opposite of distillation, meaning instead of vaporizing the desired compound, you vaporize the undesired compound, in this case alcohol. This alcohol is also reusable. How it is re-usable though, is dependent on the terpene and water content after the roto-vap collection.
If you stop here, you will most likely now have a salable vape cart oil – one that possibly even has choice terpenes left intact. If the flavor is good enough, after a QC evaluation, and lab testing, with 45%-70% THC, this might be a good enough product to sell on its own, if the terpenes are 5% or higher.
You can now market this a stand-alone product, distill it, or set it aside to combine later with a batch of distillate.
High Vacuum Distillation
Short Path Set System from USA Lab.
I drank some boiling water because I wanted to whistle.
Distillation takes the same basic ideas from earlier processes and ramps them up to an explosive new level, with dangerously high temperatures, and a stronger vacuum. Now we’re getting into our Frankenstein’s laboratory, mad-scientist phase of our journey.
With a strong vacuum, you can pull back against the forces of nature. This is done by reducing atmospheric pressure and lowering the boiling point of your essential cannabinoid oils, so that you can start separating the various chemical components. Through Vacuum Distillation this is accomplished by staggering their points of evaporation and releasing their vapors, one temperature plateau at a time, through a chilled condenser. The condenser gently cools the vapors into a liquid, your newly distilled oil, which runs down into collection flasks waiting below.
Whether you are using a semi-automated system like a thin film evaporator or doing it with lab glass and a heating mantle, as you stay busy with knobs, dials, and gauges, the process of distillation involves moving a solution through different phases of liquid and vapor by manipulating the temperature and pressure. Skilled distillers can pinpoint and capture narrowly targeted slices of cannabinoids and even terpenes that vaporize at progressive boiling points.
TFE
Artisan- X D200 from SciPhy Systems.
I must create a system or be enslaved by another mans; I will not reason and compare: my business is to create.
A thin or ‘wiped’ film evaporator, is a cylindrical machine that uses a combination of heating, and agitation, to cause controlled, layered evaporation of a liquid solvent solution. Think of this like rotary evaporation on steroids.
This one machine can perform the functions of both rotary evaporators and vacuum distillation and can be an incredible one-stop refinement option, post winterization.
A big advantage of a TFE is that it is more turn-key and requires less high maintenance supervision than high vacuum or short path distillation. Another advantage is low contact time, meaning it works quickly with little chance for degradation. Additionally, lab-scale TFE systems typically have a high throughput, relative to other options in this range.
The downside of a TFE system is that it can be expensive and may be difficult to set up and maintain, depending on the skill level of the crew/technician. You will also still need other extraction processes like ethanol or CO2 to get you up to the point of an ethanol/cannabis-essential oil slurry.
Isolate
Life is full of misery, loneliness, and suffering - and it's all over much too soon.
An ‘Isolate’ is an extract that has been further refined and purified up to 99%. Isolates can be made of THC-A, THC, CBD, and other chemicals. While making isolates gets into some pretty advanced lab work which a Ph.D. chemist would be helpful for, it can also be achieved by paying a lot of money for a preparatory liquid chromatography extraction platform.
Preparative Liquid Chromatography (High-Pressure Liquid Chromatography)
Industrial HPLC system from Lab1st.
The greater danger for most of us lies not in setting our aim too high and falling short; but in setting our aim too low, and achieving our mark.
HPLC machines are laboratory systems offered on varying scales. Scales and targeted use control price and are often dictated by how you intend to use them. Small scale systems are useful for cannabis analytical testing, while large scale systems are more likely employed for large-scale commercial isolation.
HPLC is incredibly good at separating molecules and preparative liquid chromatography (PLC) is the equipment that is used to produce 99.9% pure isolates.
High-pressure liquid chromatography works by firing the extract suspended in a solution with a solvent at high pressure through a column that has been packed with super absorbent materials, such as silica. The various components of the solvent solution are separated into different adsorbents as they are pushed through the column.
If you plan to employ any in-house use of analytical HPLC or production PLC, you will likely be using methanol as a solvent. This will require securing a Haz-Mat waste removal service from your facility at regular intervals to stay within typical regulatory requirements.
While this is one of the technologies used by most cannabis testing labs, the analytical versions of this type of equipment are small, with low throughput, and won’t work as a practical, commercial manufacturing solution.
The commercial-scale options for this equipment, on the other hand, are seriously expensive and require a high level of sophistication and experience to operate. We’re talking about the same technology that is used in oil refineries and huge pharmaceutical plants.
Setting up and running a commercial PLC system for high scale production is one of the biggest pipe dreams in this entire book, but if you can pull it off, you’ll be one of top cannabis extractors in the world!
Need help finding your way in this industry?
The Team @ My Pipe Dreams has been there and done that, and we can help.
Key Chapter Takeaways
The Do’s and Don’ts of the Dope Industry
- Do– Appreciate the importance of winterization.
- Do– Consider taking your refinement process to the next level!
- Do– Your research before deciding on refinement equipment.
- Don’t– Overlook a turkey TFE system.
- Don’t– Don’t give up on your dream of a monster HPLC column, even though we said it probably won’t happen.