Cannabis extraction is the process of using a solvent to extract cannabinoids and terpenes from cannabis flower or trimmings. Raw cannabis extract is then further processed to produce consumable cannabis products Because of its great versatility, cannabis extract is used in a variety of products including edible and tincture oil formulations, vape oils, and dabbing concentrates.
Many different solvents have the ability to separate cannabinoids and terpenes. The only strict requirement is that cannabinoid and terpene compounds must be soluble in the solvent medium.
However, not all solvents are safe for human consumption or lend themselves well to large scale production. For this reason, three types of solvents tend to dominate the cannabis industry: carbon dioxide, hydrocarbons, and alcohol.
Carbon Dioxide
At first glance, carbon dioxide may not seem like an obvious choice for a solvent. That’s because you’re probably most familiar with this compound in its gaseous and solid (dry ice) forms.
But when highly pressurized and heated, carbon dioxide becomes a liquid that retains some of its gaseous properties. Referred to as supercritical carbon dioxide, this substance can easily penetrate porous solids and dissolve cannabinoids and some terpenes.
Carbon dioxide is often touted as the cleanest method of cannabis extraction. That’s because it’s relatively inert or nontoxic at low levels. It’s also nonflammable, making the production process much safer.
Hydrocarbons
Hydrocarbons make excellent cannabis solvents. Due to their hydrophobic or nonpolar nature, they’re well suited to dissolving fat-soluble cannabinoids and terpenes.
However, many hydrocarbon solvents such as benzene are not safe for human consumption. They can also be dangerous to handle and difficult or expensive to purchase. As a result, the relatively inexpensive and easy to obtain butane and propane have become the most commonly used hydrocarbon solvents for cannabis extraction.
Hydrocarbon solvents have received a bad rap over the years due their use in illegal extraction setups. But extracts made using butane and propane are generally safe to consume if the solvents don’t contain impurities and are properly purged or removed from the final extract.
Comprehensive cannabis testing can also help detect and prevent the consumption of harmful levels of residual solvents.
Alcohol
Alcohol in the form of ethanol has more recently become a solvent of choice for cannabis extraction. That’s because it allows for fast extraction times and can handle large capacities. It’s also relatively safe when it comes to trace levels remaining in the final extract.
However, both alcohol and hydrocarbon solvents pose an operational hazard due to their flammability. This danger can be largely mitigated by using a closed extraction system, however, accidents can still occur.
While there isn’t one way to make cannabis extract, the result of solvent extraction is typically a concentrated oil. Manufacturers must further process the raw extract to create different consumable products such as cannabis tincture oil, vape oil, shatter, budder, wax, and isolate. In our next installment, we’ll discuss how cannabis extracts are further refined.