Cannabidiol (CBD) is one of many naturally occurring cannabinoid found in the cannabis plant. Both hemp and marijuana can contain CBD, though today CBD products are primarily created from hemp. Marijuana often contains high amounts of THC, the high inducing compound in cannabis. Hemp, on the other hand, can only contain a trace amount.
While there is a growing market for smoked hemp flower, the most common way to consume the beneficial phytocompounds is via tinctures or capsules. In order to be consumed in this manner, the naturally occurring compounds in the plant must be extracted into an oil. This oil is then used as the primary ingredient in these and many more consumable and topical products.
The method of extraction and processing of a hemp extract can have a big impact on the contents, quality, and purity of a given product. In this article, we cover the various methods of extraction used to create CBD oil from hemp. Keep reading to discover what goes into the creation of a CBD product and what types of extraction and processing are preferred.
Everything Begins with Hemp & Here's Why
Thanks to the 2018 Farm Bill, hemp has finally been given a definition separate from marijuana. This definition lifts hemp out of the controlled substances act, making the plant and its extracts legal. The definition of hemp is cannabis containing 0.3% or less THC by dry weight. This legal status and the high-CBD content of many strains have led to hemp being the primary source of CBD oil extraction for products sold to the public.
It is possible to find high-CBD products extracted from marijuana, but they are also often high in THC and thus today must be sold as a marijuana product through appropriate channels. These products are outside the scope of this article, and any CBD product you find freely available for sale online and in retail stores will be hemp-derived.
This legal approval has spawned an increasingly large number of growers and extractors who seek to produce the highest quality hemp possible. Today you'll find a wealth of clean, quality products sourced from organically grown, non-GMO, domestic hemp plants.
Comparing CBD Oil Extraction Methods
As we discussed in the intro, the hemp plant first needs to undergo an extraction process to create a crude extract. This is the first step in transforming these valuable plant compounds into one of the many CBD products available on the market today.
The general idea of hemp extraction is that a solvent is passed through plant material in order to separate out the active compounds in the bulk plant materials. The resulting cannabinoids, terpenes, and other plant compounds like chlorophyll are then collected as oil and further processed before making their way into an end product.
The following methods are all commonly used to create the various spectrums of CBD oil extracts found on the market today. Each method carries limitations and benefits which we cover below:
Supercritical CO2 Extraction
CO2 extraction is widely considered to be a fantastic method used to create CBD-rich extracts. This extraction method puts carbon dioxide under high pressure while maintaining a low temperature. The gas is transformed into a liquid due to the pressure and then passed through the plant material with up to a 90% extraction efficiency. The resulting extract a highly concentrated, totally pure oil extract.
Check out the following video for an example of how this extraction method works:
This process requires expensive equipment and experienced operators. Because of this, the resulting oil is often higher priced for the end consumer but enables the highest quality products to be produced.
When compared to CO2 extraction, ethanol extraction is a lower-cost method, but still used by many companies on the market today. Despite the lower cost, this extraction method can still be used to create high-quality extracts though it may require more expertise and post-extraction processing.
This extraction method utilizes an alcohol solvent - most commonly ethanol. Ethanol is 'Generally Regarded as Safe (GRAS)' by the FDA. It is commonly used as a food preservative and additive found in many products at the grocery store.
Ethanol is a polar solvent which means it will mix with water and dissolve water-soluble molecules in addition to the desired cannabis compounds. Chlorophyll is one of the compounds that ethanol will co-extract along with the cannabinoid filled oil. The result is a dark-colored oil with a bitter and grassy flavor.
The chlorophyll can be removed from the oil using post-extraction filtering methods, but the process can also remove some of the cannabinoids resulting in a lower quality CBD oil product. Some ethanol extractors cite that the water-soluble component extraction can be mitigated by using cold extraction temperatures.
Assuming an experienced operator, the result of this extraction method can be very favorable, even comparable to CO2 extraction in quality. That being said, with a less experienced extractor, there is more room for error and possibility for solvent contamination or lower quality end product.
This early extraction method was created using a light hydrocarbon solvent like to extract cannabis oil. Commonly butane, pentane, propane, hexane, isopropyl alcohol or acetone are used as solvents. These hydrocarbons have a low boiling point and can be easily used to extract CBD oil.
This cheap and easy method of extraction comes with a variety of issues that make it non-ideal. The resulting oil usually contains a lower concentration of terpenes and cannabinoids like CBD and a higher concentration of THC. There is also unsafe residue that can remain that may interfere with immune function. This extraction method proved to be both dangerous and inefficient and is thus rarely used by commercial CBD companies today.
One of the lesser-used extraction methods is called lipid extraction. This method uses the fats, or “lipids”, to absorb and encapsulate the hemp-produced compounds. Often organic coconut oil is used in this extraction process. Lipid extraction does not require the use of any harsh solvents or CO2. It is not a popular method of extraction, though you may find some boutique companies using it.
Crude Extract Purification & Processing
After a crude CBD extract is created, there are some additional, optional steps that are performed to get the product ready for consumption.
Purifying via Winterization
The high pressure and/or high temperatures in the initial extraction process brings with it a wide range of fatty acids, plant materials, chlorophyll, cannabinoids, and terpenoids from the plant material. An optional process called winterization which works to further purify the extract and remove the unwanted components.
This process is essential for almost all crude extracts unless the extract was created using low-temp ethanol extraction.
The process of winterizing consists of completely mixing the CBD extract in 200 proof alcohol and freezing it overnight. In the morning the cloudy mixture is ready for filtration. This process is done by running it through a paper filter into an extraction jar.
The alcohol is removed from the filtered end product through warming until it evaporates. This is made possible because the alcohol has a lower boiling point than the oil.
These 'raw' cannabinoids must be activated in order to produce the desired molecules. For example, CBDA must be activated to produce CBD. When a low-temperature method like supercritical CO2 extraction is used, the original acid forms of the cannabinoids may be produced. In order to activate these cannabinoids and removed the acid molecule, the CBD extract undergoes a process called decarboxylation.
Though it sounds fancy, decarboxylation is simply the heating of an extract. Through this heating process, the acid molecule is removed and the active compound is produced. This process can be performed either before or after extraction. Learn more about decarboxylation in our article on the subject.
Despite being less popular, the 'raw' molecules are showing promise as they interact with the body differently than the 'activated' or non-acid forms of these same substances. For example, THCA is non-psychoactive, while THC is psychoactive. Limited research and anecdotal user experiences point to these raw cannabinoid forms providing some unique therapeutic benefits.
This is driving some companies to include the acid forms of these cannabinoids in addition to the activated non-acid forms. With that being said, unless specifically outlined as a 'raw' product, all CBD products on the market have been decarboxylated to activate the compounds.
Isolation or Removal of Unwanted Compounds
The crude extraction and processing up to this point will create a usable extract containing a full profile of terpenes and cannabinoids. This extract is ready to be used in the creation of end products for consumers, but often there are additional processing steps performed.
Using processes like distillation and chromatography, individual or groups of compounds are either isolated or removed from the extract. Examples include CBD isolation via distillation (which we cover below) or THC removal via liquid chromatography to create a broad-spectrum extract.
How is CBD Isolate Made?
Today you'll commonly find single-molecule CBD isolates. In their purest form, these isolates are a crystalline white powder comprised of 99%+ cannabidiol. All other cannabinoids, terpenes, plant materials, oil, and chlorophyll is removed in the creation of this powder. All that is left is naturally sourced CBD crystals that carry no odor or flavor.
Chemists use short path distillation or chromatography isolate the individual compounds in the material - in this case, cannabidiol.
Consumers often find CBD isolate attractive because it is THC-free. You should understand that while isolate is versatile, products based on this type of extract are not as effective as an oil containing a full or broad-spectrum cannabinoid profile. The single-cannabinoid profile is less effective due to the lack of cannabinoid and terpene synergies known as the entourage effect.
The Big Sky Extraction Process
Here at Big Sky Botanicals, we produce a broad-spectrum product line that contains a full-spectrum profile of cannabinoids and terpenes with only the THC removed.
We outline in detail how our products are made showing the extraction and processing methods we use to craft the high-quality extracts used in our products.
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