Common Methods of Cannabis Oil Extraction
In this article:
- Reasons for the Extraction Process
- Cannabis Extraction Is Nothing New
- Extractions Based on Plant Type
- Solvents Vs. Solventless Extracts
- Hash (Solventless)
- Kief (Solventless)
- Rosin (Solventless)
- Butane Hash Oil (BHO; Solvent)
- Propane Extraction (Solvent)
- Alcohol Extraction (Solvent)
- Tinctures (Alcohol Extraction)
- Rick Simpson Oil (RSO; Solvent)
- Supercritical Fluid Extraction (CO2 Extraction; Solvent)
- Molecular Separation (Solventless)
- Live Resin (Solvent)
- Leave the Extraction to the Professionals
For those who want to get the benefits of cannabis without smoking or otherwise using the entire plant, numerous extractions processes can get cannabis oil out of the plant. From there, manufacturers can create cannabis oil, edibles, capsules, vape products, or other items.
Essentially, cannabis extraction will get rid of the compounds in the plant that you do not want while keeping the original plant’s cannabinoids and active terpenes.
Reasons for the Extraction Process
There are multiple reasons to extract cannabis oil from the cannabis plant, including improving the potency over the fresh herb. It also gets rid of the compounds that you do not want. It is also simpler to find the dosage and concentration for cannabis oil extracts than in a whole plant since more of the compounds you want (cannabinoids and terpenes) are present.
The extraction will keep the cannabinoids, flavonoids, and terpenes to the greatest extent possible. It will also remove as much of the chlorophyll, fatty acids, and waxes. The first group enhances the concentrate’s taste, potency, and smell, while the second group can be dangerous or taste bad.
Cannabis Extraction Is Nothing New
Before getting into the various methods of cannabis oil extraction, keep in mind that this process is nothing new. People have been doing it for thousands of years. We have just created additional methods and refined the process in recent years. You can find records of people using hash as early as the year 900, where people would eat it. There are also many old records of cannabis tea and tinctures.
During the turn of the millennium, hash was popular throughout the Middle East. Many feel that Napoleon, along with his troops, may have brought Egyptian hash to Europe in the 1800s or so. There are records of French doctors suggesting hashish during the 1840s and evidence of a Club des Hashischins in Paris not long after. In fact, people in the United States used cannabis tinctures until 1942, and their popularity continued in the United Kingdom until 1970.
Extractions Based on Plant Type
Some of the variations in the cannabis oil extraction method will depend on the plant type you use. You should choose your cannabis strain based on the desired results. If you want an extract with high levels of CBD and low levels of THC, look for that in the plant strain. The opposite is also true.
All cannabis extraction methods should start with organic cannabis grown without chemical fertilizers or pesticides. This prevents the presence of those chemicals in the final product.
Solvents Vs. Solventless Extracts
There are two main categories of cannabis extracts, those that use solvent and those that are solventless. As the names imply, one involves the use of solvents in the extraction process, and the other does not. Production of solventless extracts will not include any foreign substances, except for water. Instead, they rely on heat, a sieve, and pressure.
Solvents will use substances like butane, propane, or alcohol. People keep discovering new solvent-based methods of cannabis oil extraction, but you should always use caution when experimenting yourself or buying oil made from a new process. The chemicals may explode during the process if done incorrectly. It is also possible for some residual solvent to make it into your final cannabis product. That is just one of many reasons to get certificates of quality always before buying cannabis products.
Hash is among the oldest products extracted from cannabis. There are several extraction techniques. Of these, the most common is to use ice water. The ice water will separate the plant matter from the trichomes containing the essential oils. The separated substances will stick together. You let them dry and press them to finish making the hash.
You can also make hash via dry sifting. Start with frozen buds that the screen will break down into tinier pieces. This separates the trichomes from the rest of the plant, having them fall through your sieve, where they press and form a hash-like consistency.
Another solventless extraction method produces kief, which are the white crystals on the cannabis flower that are small and sticky. It looks like pollen or powder and is rich in trichomes. You may also know them as the trichomes or resin glands, and they are the part of the cannabis plant with the largest concentration of active cannabinoids and terpenes. To separate the kief during extraction, you need a three-chamber grinder. The kief will end up in the bottom chamber.
Rosin is another solventless extraction method, and it only requires pressure and heat. That combination will cause the juice to run out of your hash, bud, or kief. The extract will be translucent and juicy, with a sap-like consistency. This rosin can maintain the plant’s aromatic terpenes and have potency as high as 70 percent THC.
Testing shows that rosin can effectively extract the terpenes and cannabinoids from the cannabis plant without any risk of toxic residual solvents left behind. It is popular for its simplicity and the ability to do it at home, to some extent. People have produced potent rosin extracts using baking parchment, heatproof gloves, a hair straightener, and a tool to collect it.
Butane Hash Oil (BHO; Solvent)
As the name implies, Butane Hash Oil (BHO) is made with butane. This continues the trend of using hydrocarbons like butane, propane, and hexane in extractions like corn and canola oil.
This process involves running a solvent through the cannabis plant matter. This process will cause the oils you want to come out of the plant in question. Afterward, the solution is placed in a vacuum and heated, since butane evaporates at low temperatures. This ensures that all of the solvent gets out of the extract. The extract from this process is referred to as shatter. The extract is clear and usually includes terpenes, CBD, and THC. True shatter is a harder version of butane hash oil, and it requires low terpene content to avoid a soft extract.
This process is ideal for producing extracts with incredibly high potency, such as up to 90 percent. There are, however, some hazards associated with this method. Butane burns easily while as a gas, so you must carefully manage the temperature to avoid an explosion. Also, you will need a system that recycles and removes the butane, so there is no residual butane in your extract. The process must include analytical testing to confirm no butane is present since it is harmful.
Propane Extraction (Solvent)
Using propane to extract cannabis oil is nearly identical to using butane. The high pressure will ensure the propane remains liquefied. Propane has a lower boiling point than butane so that the extraction can take place at lower temperatures. You still need to take precautions to ensure you remove as much of the chemicals as possible.
Alcohol Extraction (Solvent)
Several types of cannabis extraction use alcohol. These involve soaking the plant in alcohol and then removing the plant material. You then filter the liquid and remove the alcohol via a process like evaporation. Usually, alcohol extraction is perfected at the normal atmospheric pressure with carefully controlled temperatures. You need to take the process slow and steady to avoid the ethanol catching fire.
A significant challenge to this method is that the solvents used have inherent polarity. As such, it is likely to mix with the water where it would dissolve chlorophyll and other water-soluble molecules. That would be problematic as chlorophyll in the extract can lead to a bitter flavor.
A significant benefit is that you do not have to worry about accidentally leaving residual chemicals that are toxic in the cannabis extract. It also makes it easy to extract the compounds you want simultaneously.
Tinctures (Alcohol Extraction)
Tinctures are incredibly common types of cannabis oil. These are liquid concentrates produced via alcohol extraction. The alcohol will pull the terpenes and cannabinoids out without any need for heat. The lack of heat makes tinctures safer to extract than the BHO method. As a bonus, tinctures can also incorporate added flavors, appealing to those who want to enjoy cannabis without the bitter taste.
Rick Simpson Oil (RSO; Solvent)
Another solvent-based extraction method is Phoenix Tears or RSO. This method is named after Rick Simpson, who created the extraction method. Start by soaking the entire plant in pure isopropyl alcohol or naphtha. This will draw the cannabinoids out. Let the solvent evaporate, and you will notice the extract is tar-like. You can then take RSO orally or choose to apply it on your skin.
Supercritical Fluid Extraction (CO2 Extraction; Solvent)
With supercritical fluid extraction, you do not need to have any chemical solvents at all, which makes it appealing to many. Instead, these extracts rely on carbon dioxide, so they are also called CO2 extraction. You compress the carbon dioxide, so it turns into a supercritical fluid. The resulting fluid will work similarly to hydrocarbons, stripping essential oils out of the cannabis plant. At the end of the process, any leftover CO2 will evaporate. You need professional, expensive equipment to complete this extraction process, so you are unlikely to find someone trying it themselves.
Thanks to the use of professional equipment, you lose less valuable material and get higher yields. That equipment also makes it possible to extract the specific compounds you want by adjusting runtime, pressure, and temperature. Cannabis oil extracted via this method does require analysis for concentrations since the same process can lead to varying concentrations.
The unique thing about this method is that the supercritical fluid combines properties of gas and liquid, allowing for the extensive dissolution of the plant matter. CO2 extraction like this is also easier to control than BHO. It even produces a cannabis extract containing additional terpenes. While BHO produces 0.5 to 3.5 percent terpenes, CO2 has a concentration of up to 10 percent.
Molecular Separation (Solventless)
Another method of extraction is molecular separation, also known as short path distillation or high vacuum distillation. The method lets you treat molecules using minimal thermal degradation to separate terpenes and cannabinoids from the rest of the plant. The entire process takes place in a vacuum with levels under 0.01 mm Hg.
That vacuum means that you can distill products with a high boiling point at moderate temperatures. This helps the resulting product, as you do not expose the plant to high temperatures for a long period. As a result, the compounds you want, like terpenes, experience minimal thermal degradation.
Live Resin (Solvent)
One of the newest extraction methods is live resin. You harvest the cannabis plant fresh and then freeze it right after harvesting. The method uses butane extraction as its basis, but it is different enough to be a separate method. This distinction comes from the reduction in waiting time. There is no need to dry and cure your cannabis plants before extraction as you would with other methods. That is important, as drying and curing can take as long as 70 days.
Live resin extraction can also preserve the terpenes to a higher degree than other methods. Since this method is still new, it is very rare and tends to be expensive.
Leave the Extraction to the Professionals
Even if some of the above methods seem straightforward, you should keep in mind that most require a deep understanding of chemistry. You will need a fume hood or other safety equipment for most of the methods. As such, you should not try most of them at home. There is also the risk that you will not complete the extraction process correctly and create a product that is not safe if you attempt to extract the cannabis oil yourself.
You should be able to find cannabis oil created using each of the extraction methods above, although some are much more common than others are. To stay safe when purchasing cannabis products, always make sure to choose a company that offers certificates of quality or analysis. This will let you confirm that no solvents or chemicals make it into the product and can also confirm the potency.