The Pros and Cons of Various Cannabis Extraction Methods
There several ways to extract compounds from the cannabis plant. Chris Bond reviews some of the key extraction methods plus the benefits and pitfalls that come with them.
In the search for a better high, more potent remedy, or just purely because they could, folks have been extracting various components from the cannabis plant for a very long time.
With the advent of more legitimacy to the business of cannabis extracts, the ever-increasing interest on the part of the consumer, and the more research dollars governments and institutes of higher learning are investing in extraction research, the interest in learning more about it has increased.
The primary cannabinoids most people know about extracting are of course the two biggies: tetrahydrocannabinol (THC) and cannabidiol (CBD), but there are many other cannabinoids that can be extracted. Cannabigerol (CBG), cannabigerolic acid (CBGA), tetrahydrocannabinolic acid (THCA), cannabidiolic acid (CBDA), or cannabichromenic acid (CBCA) are a few more of several other potential cannabis extracts being sought for research or use in marketable products.
For those with an interest in trying to extract any of these, there are options at several price points, levels of sophistication, and of course, varying costs to perform them. Extraction methods are also used to make other consumable products like hash or hashish oil.
So, whether you have sterile lab-like conditions or are just tinkering in your musty basement, read on to learn about several available methods of extraction or distillation, and things to consider for each listed (more or less) from simplest to most complex.
Solvent extraction is the most common CBD extraction method. It is performed using any number of solvents such as ethanol, petroleum ether, naphtha, butane, isopropyl, or other types of alcohol. It is most often done by placing plant material such as buds, leaves, or trimmings in a container and pouring a solvent over top of it. The pour-through liquid is then collected, and the solvent is allowed to evaporate. What is leftover is a concentrated oil that can be used for various applications.
Solvent Extraction Pros:
- Inexpensive to perform as many solvents are readily available. Other materials needed such as containers are also often on hand or easily obtained at commonly shopped at stores.
- It’s quick, so large volumes can be produced in a relatively short amount of time; it’s especially good for distillate products.
- Among the easiest if not the easiest of all extraction methods.
- A complete extraction, as solvents generally target all the different trichomes, as well as other plant constituents.
Solvent Extraction Cons:
- Among the most dangerous method of extraction as most solvents are highly flammable. To be safely performed, a fume hood should be used if in closed quarters or should be done outside.
- Destructive to the plant tissue. Many solvents (ethanol alcohol, butane, and propane ) destroy cannabinoids and chlorophyllas it passes through the biomass. For this reason, it is not a selective process to isolate certain cannabinoids such as other extraction methods can do.
- Often requires additional processing to be crafted into a usable product.
Olive Oil Extraction
One of the other DIY extraction methods (and possibly one of the oldest) is olive oil extraction. With olive oil extraction, the plants must be heated to activate compounds in the cannabis. Then the heated cannabis is added to olive oil and heated again. The oil is infused with the cannabinoids by this process and it can be consumed.
Olive Oil Extraction Pros:
- This is a safe method of extraction as it can be performed with almost any heat source.
- Inexpensive as the only costs are the cannabis and the olive oil.
- Among the simplest methods to extract cannabinoids.
Olive Oil Extraction Cons:
- The finished product is perishable and cannot be stored for long periods of time before needing to be consumed. It should be stored in a dark, cool place until being used.
- Olive oil extraction does not yield a highly concentrated form of cannabinoids and therefore more of the product needs to be ingested to have its desired effects.
- It’s not a smokable extract.
Dry Ice Extraction
This is another DIY extraction method, dry ice will extract any cannabinoid in the trichrome. With dry ice extraction, cannabis resin is isolated to get concentrated THC. Most people who make hash prefer using dry ice to other methods as it is many times faster, often only taking a few minutes.
Dry Ice Extraction Pros:
- Fast, if not the fastest method to make hash.
- Easy to perform; no extensive training required.
- Since there is no drying of the product required, it is ready as soon as it is shaken from its container.
Dry Ice Extraction Cons:
- Dry ice has an extremely low temperature that can cause burns if touched with bare skin.
- Dry ice turns directly into gas once exposed, so it needs to be used quickly.
Closed Loop Hydrocarbon Extraction
Hydrocarbon extraction is a far more complex and graduated version of the solvent method. This method employs some of the same solvents such as butane, but it is performed in a laboratory setting using highly specialized equipment. This method is not for the
DIYer and is strictly in the realm of professional extractors. Those performing hydrocarbon extraction on cannabis must consider safety features in their setup that account for constant monitoring of the gas being used and ignition points, adequate ventilation, and have some type of fire-suppression system as failure during this process can cause an explosion.
Hydrocarbon Extraction Pros:
- Extraction rates are quick.
- Extract using this method can be highly potent.
- Equipment is less expensive than that needed for CO2 (see below) extraction method.
Hydrocarbon Extraction Cons:
- The facility needed to perform hydrocarbon extraction is costly to setup.
- The required equipment is also expensive.
- It is difficult to (legally) scale up production as the amount of hydrocarbon allowed on site at one time is regulated.
Short-path distillation is a process of separating various cannabinoids into highly concentrated forms. This takes place by heating samples of cannabis extracts at various degrees to collect different compounds at their respective boiling points. A vacuum draws up the condensate into tubes where they are separated. Each individual cannabinoid, terpene, or other desired compound has a unique boiling point and weight that can be selected for in short-path distillation.
Short-Path Distillation Pros:
- Purity — short-path distillation can produce products with up to 99 per cent purity.
- Machines are relatively easy to use.
- Large quantities of different cannabis strains can be distilled with the same equipment
Short-Path Distillation Cons:
- Among the most expensive methods to produce cannabis extracts. Equipment ranges from thousands of dollars to tens of thousands of dollars.
- Any pesticide residue on the plant material may still be there after distillation.
CO2 extraction is arguably the most advanced method of cannabis extraction. It is the costliest method but can produce the safest end-product when done correctly. This is performed with a three-chamber setup which holds pressurized CO2 in the first chamber, dried plant material in the second, and finished product in the third. In essence, the CO2 is pumped from the first chamber into the second at a state of matter between a liquid and a gas, known as supercritical CO2. This runs through the plant material absorbing the cannabinoids. In the third chamber the CO2 is then separated from the resulting oil which falls to the bottom for collection.
Different pressures can be used to achieve different results depending on the product being sought.
CO2 Extraction Pros:
- Produces a high-quality product retaining the desired properties of cannabis.
- Specific cannabinoids can be isolated.
- No residual contaminants, making it suitable for vaping.
- Much safer than hydrocarbon extraction.
CO2 Extraction Cons:
- Among the most expensive if not the most expensive extracting equipment.
- System is complex and requires a skilled technician to perform the process.
- Can be a slow process compared to other methods.
There is a cannabis extraction method out there for every skill and risk-tolerance level, and one for every budget and physical space restriction. Whichever is attempted, make sure all safety protocols are followed to the letter; nothing ruins a high faster than getting injured trying to achieve it.