CBD oil has become a highly sought-after product as its far-reaching health benefits come increasingly into the spotlight. When CNN aired the three-part docuseries “Weed” in 2013 (featuring esteemed neurosurgeon Sanjay Gupta), CBD oil became more popular than ever. CBD oils and tinctures are the most popular forms in which to consume CBD, and arguably yield the most benefits.
We’ve talked a lot about what CBD is and where it comes from, but how exactly is CBD oil made from the cannabis plant? Here we cover some of the methodology behind extracting CBD and making CBD oil.
CBD is found in its highest concentration in the resin that forms in the glandular trichomes on the flowers of the female cannabis plant. There are smaller trichomes on the stalks and leaves of industrial hemp plants, but they don’t contain the same amount of resin. Historically speaking, industrial hemp is a taller, skinnier, more fibrous and less resinous type of cannabis plant.
Unfortunately, due to the legal limitations of growing marijuana in the United States, the most resinous plants, which contain higher concentrations of CBD, cannot legally be sourced here except in states that legalized hemp cultivation under the Farm Bill of 2014, like Colorado. Newer industrial hemp varieties are now being cultivated stateside in these “green” states to bear more flowers and higher cannabinoid yields. It’s just a matter of time before the law catches up to the demand. Higher-CBD hemp plants can also be processed abroad, and their CBD imported as long as it sticks to the 0.3%-THC-or-less rule.
Ideally, the sourced CBD comes from the whole hemp plant and is processed minimally, yielding the highest-potency CBD oil without altering the compound in any way. A whole-plant CBD oil extract is also rich in other nutritive compounds—amino acids, omega-3 fatty acids, chlorophyll, terpenes/terpenoids, and other less-discussed nonpsychoactive cannabinoids such as cannabidivarian (CBV), cannabinol (CBN), and cannabigerol (CBG). The synergy of these compounds is said to have an “entourage effect” when consumed, meaning that there are cumulative health benefits to taking in all these compounds together as opposed to CBD by itself. When purchasing CBD products, it’s important to look for “full-plant extract,” “whole-plant extract,” or “full spectrum” on the labels—this tells you that the CBD oil is made using the whole plant, including the flowers (which contain the most resin/highest concentration of CBD and other cannabinoids). Synthetic CBD can also be found on the market, and it’s entirely possible that big pharma will soon create its own, consistent single-molecule CBD isolate, but we and other CBD advocates know that synthetics generally will not have the same benefits as whole-plant derivations.
CBD newbies should note that CBD oil is not the same thing as the hempseed oil or hemp oil that one finds in natural-food stores and grocery stores—these products can be effective nutritional supplements, but they do not contain CBD. These oils are made from hempseeds only, which are pressed and sometimes refined depending on what the oil will be used for.
So how is CBD oil made from the cannabis plant? There are a few different extraction methods:
We’re going to keep it simple here, but there are actually three types of CO2 extraction—supercritical, midcritical, and subcritical. The difference between these methods has to do with the temperature and pressure at which the extraction systems are run. But it is said that the supercritical method is the most common, and also that systems capable of running the supercritical method are capable of running subcritically as well (but not vice versa).
Supercritical CO2 essentially is carbon dioxide that has been heated above “critical” temperature (31.1° Celsius) and pressure (1,071 PSI). This gives CO2 the properties of both a gas and a liquid, turning it into what’s called a supercritical liquid. This allows the CO2 to both pass through porous matter and also dissolve materials, making it an ideal solvent, because it is safer than other chemical solvents.
When supercritical CO2 is used as a solvent to extract CBD, an extractor chamber is filled with ground cannabis material (aka “trim”). Pressurized CO2 is forced into the chamber, where it dissolves the cannabinoid compounds in the cannabis trim. The supercritical CO2 then carries the cannabis oil through a pressure-release valve and into a cyclonic separator. Here, at lower pressure, the CO2 and cannabis oil separate again. In some “closed-loop” extraction systems, the CO2 moves back into the extractor and gets reused. The remaining cannabis oil, plant waxes, and resins move from the separator into a collection vessel. From here the cannabinoid substance is further processed and filtered based on the CBD product that is being manufactured.
CO2 extraction is probably the most well-regarded scalable extraction method, for good reasons. CO2 is a commonly occurring, natural substance. It’s used to carbonate beverages, and is present in other foods. CO2 extraction has also been used to decaffeinate coffee and to make essential oils. It’s one of the safest ways to pull out potent CBD without damaging it or contaminating it. The only downside is that CO2 extraction is the costliest method, requiring expensive equipment and people to run it who know what they’re doing.
Commonly, when people talk about oil extraction, they mean that olive oil is used as a solvent to pull CBD from the cannabis plant. This method is quite simple. First, the raw cannabis material needs to be heated in order to activate the cannabinoids within. This process is known as decarboxylation (or “decarbing” among cannabis aficionados)—chemically speaking, this means that cannabinoid compounds shed a carboxyl group from their chemical makeup. This is what in fact turns CBDa (cannabidiolic acid) into the compound CBD. The temperature and duration at which to decarboxylate cannabis materials varies greatly. For the purposes of this brief explanation, suffice it to say that the cannabis must be heated first for the oil extraction method to work.
Once the plant matter is heated, it is then added to olive oil, which is heated to 100° C/212° F for at least an hour (and up to 2 hours). Once this is done, the oil should contain the CBD and other cannabinoid compounds from the initial cannabis trim, and is ready to consume.
This method is extremely safe, and far less expensive than CO2 extraction, but it has many limitations. For one thing, it’s very difficult to scale, as this method of extraction produces low yields. The resulting CBD oil from this process is also perishable, and must be stored in a cool, dark place and used within a certain time period. Unlike CBD oil made via the CO2 or alcohol/liquid solvent methods, CBD oil made this way cannot be concentrated; the olive oil cannot be evaporated away or separated out, which means you’ve got to consume a lot more of it to get the same benefits as a more concentrated product. If you’re looking to make small batches of CBD oil at home, this could be a viable method, but keep in mind these caveats and the fact that there are many variables beyond one’s control.
ALCOHOL/ETHANOL/LIQUID SOLVENT EXTRACTION:
This extraction method employs an alcohol or other chemical solvent (such as ethanol, butane, or hexane) to strip cannabis material of its cannabinoid compounds. The plant material is generally put into a container and then soaked or “washed” with the chemical so that CBD and other cannabinoids transfer into the liquid. Because the solvents used have such low boiling points, it’s easy to evaporate them off once the transfer is done, leaving behind the concentrated cannabinoid compounds in the form of an oil.
This process is pretty straightforward, and can be done on a small or large scale, but the end product does have some drawbacks. These solvents pull out not only the cannabinoids in the plant material, but some chlorophyll, too, which can lead to unpleasant effects and have a harsh flavor. This can be filtered out, but not without losing some of the oil’s potency. Also, some solvents used in this process, like butane, may irritate the lungs (if the oil is used for vaping, for example). These solvents also may contain other harmful contaminants. The liquid solvent process is the most dangerous, as well, as butane, ethanol, and the like are highly flammable.
We believe that it’s important to understand where your CBD oil comes from, and the different ways it can be extracted. The three main methods are all viable and popular ways to make CBD oil, but CBD Movement recommends an oil that is made via CO2 extraction because it is a safe, tried-and-true method of yielding a clean, potent, full-spectrum CBD product for maximum benefit.