When most people think about marijuana consumption they think of the traditional, and at times stereotypical, crushed flower rolled into a joint, or smoked in a bong. While those traditional methods are both perfectly fine, and entirely effective, there are those who are looking for something a little bit stronger. That’s where cannabis extracts and distillation comes into play.
What are Cannabis Extracts?
For those who want a little bit more zip in their cannabis experience, there are extracts. Also known as cannabis concentrates, extracts are exactly that: a condensed and concentrated form of the plant’s active chemicals.
Examples of cannabis extracts include: kief, dry sift, hash, butane hash oil, rosin and more.
Cannabis extraction is a process that involves the use of potentially dangerous solvents including: alcohol, butane and propane, or dangerously pressurized CO2, in order to separate the desired cannabinoids from the plant matter.
What is Cannabis Distillation?
The cannabis distillation process is known to create extremely potent extracts, creating a THC percentage somewhere between 90 and 99 percent. The extracts mentioned above, such as butane hash oil (BHO), clock in between 60 and 80 percent, while just consuming bud the old fashioned way will yield you only 15 to 20 percent.
Here's a quick breakdown of how it works:
Molecules such as THC and CBD have higher varying boiling points. Short path distillation uses vacuum pressure, steam, and heat to manipulate boiling points so that cannabis can be purified and distilled into more powerful compounds, leaving the rest behind. A distillate may be passed through this process multiple times to create an even more pure substance. What remains in a THC distillation is a clear and translucent gel that looks a bit like honey.
Why Use a Vacuum Pump?
Once the chemicals have had a chance to do their thing removing the “good stuff” from extraneous they need to be evaporated off to leave only the extracted material behind. Because we’re not talking about water evaporation, the temperatures required are quite high, and the overall time that it can take is intense.
Here’s where science comes to the rescue for anyone hoping to create their own extracts in volumes larger than a few grams at a time: cannabinoids in a vacuum evaporate more quickly and at a lower temperature. A vacuum pump and an airtight container can save a lot of time and headache, while reducing the chance of costly mistakes.
Want to learn more about vacuum pumps? Check out this Vacuum Pump Buyers' Guide.
What Kind of Vacuum Pump Do I Need for Cannabis Distillation?
Many experts recommend using a dry pump for your extraction needs, as wet pumps rely on parts that can be dissolved by some extraction chemicals, which causes any number of headaches you don’t need. Overall, however, there are four key factors to consider:
Depth of Vacuum and Flow Rate
The depth of vacuum you will need will depend on your desired application. For distilling cannabis, vacuums in the medium to high range are most likely appropriate. The volume of your system will also be important here. A system with a low volume will not need a large flow rate pump. Larger systems, however, will need significantly more vacuum pull.
For example, if a user has a vacuum oven used for purging low-boiling point impurities out of cannabis, high-vacuum depths are required to fully purge some solvents in addition to heat. If the oven is small, a small direct-drive pump can be used to quickly evacuate the system, while for a larger volume oven, a larger (higher free-air-displacement) pump may be required.
Wet or Dry Operation
Some applications need the deeper vacuum that only oil-sealed pumps provide, but a dry or oil-less pump is a great fit for most cannabis distilling. It is also corrosion resistant, which should contribute to longevity. That said, there are many die-hard oil pump users out there who like their oil pumps just fine.
Type of Unit
Finally, the type of unit chosen is important. Those looking for a pump to distill cannabis would likely be looking among the following types:
- Diffusion Pump: These gas-jet pumps use heated oil, which boils and captures gaseous molecules, pushing other particles with it and creating a vacuum. They use silicone oil or polyphenyl ethers, which can be expensive. Even so, these pumps are hardworking and highly reliable.
- Rotary Vane Pump: These high-performance pumps tend to be a cheaper option, but they also use oil, which can drive costs up. They can reach ultimate vacuum levels and have variable displacement capacities, but they do require regular maintenance to keep them running over the long term.
- Diaphragm Pump: Diaphragm pumps don't use oil. They are therefore corrosion resistant and involve very little maintenance. As a result, they come at a higher cost.
- Hybrid Pump: These pumps have both a diaphragm and rotary vane; the diaphragm keeps a negative pressure on the oil in the rotary part of pump, preventing solvents or contaminants from condensing in the oil. As a result, the oil in these pumps lasts up to 10 times longer than in other oil pumps. They are low maintenance and corrosion resistant so, although they cost more, they tend to save money over time.
- Scroll Pump: Scroll pumps are dry pumps that use spiral scrolls to compress air vapors. Because they are oil-less, they require very little maintenance. However, they do come at a higher up-front cost. Scrolls also need to be replaced after every 40,000 hours of use.
No matter what type of pump you choose, proper maintenance is key to keeping them working hard for many years to come. A cold trap or vacuum trap should always be used to catch vapor escaping from the reaction vessel and protect the unit from caustic chemicals. Oil should be changed in oil-based pumps according to the manufacturer's directions. Be sure to consult the product manual for your pump to ensure it is properly maintained over time.
Aren’t Vacuum Pumps Expensive?
This is really more a question of value than it is a question of cost. As mentioned above, cannabis distillation (including the use of a vacuum pump) is a full 70 percent plus more concentrated than the bud that you’re buying. It doesn’t take long before the savings involved make the long term value clear.