Extraction Methods for Making Cannabis Concentrates
Cannabis flower and pre-rolls have a relatively straightforward path from the growhouse to your rolling tray: After harvest, the buds are dried and cured before they are packaged or rolled up for your enjoyment. But what about the waxes, oils, capsules, and other products that line the dispensary shelf? Those products are all made with cannabis extract that contains high concentration of phytocannabinoids and sometimes terpenes, drawn from the same cannabis flower that you can bring home and consume.
Have you ever wondered how cannabis extracts are made? There are multiple extraction methods in use, each with their own pros and cons. Producers use different methods to develop a range of extract products with unique consistencies, flavors, and applications. Here, we’ll cover four common cannabis extraction methods that use a solvent to draw out phytocannabinoids and terpenes.
What is cannabis extraction?
Extraction is a process by which phytocannabinoids and terpenes are separated from cannabis plant material to create a highly potent extract. There are many methods by which extraction can be performed and the final product created, each of which results in a concentrate with unique characteristics like consistency and color.
Extraction can be a highly scientific process that uses sensitive, advanced equipment1, or it can be a more basic mechanical process that uses only heat and friction. The concentrates and oils you’ll find on dispensary shelves, though, have typically been created with state-of-the-art equipment and artisanal extraction techniques that producers have spent years perfecting.
4 common cannabis extraction methods
These four cannabis extraction methods are among the most commonly used to create the concentrates you buy at a dispensary2.
CO2 extraction
CO2 extraction, and more specifically supercritical CO2 extraction, leverages high pressure and heat to make carbon dioxide behave simultaneously as a liquid and a gas3. This supercritical CO2 acts as a solvent, drawing compounds out of cannabis flower. This method is also commonplace in the food and beverage industries, used in the production of beer, coffee, teas, and fruit extracts4.
Supercritical CO2 extraction is often done by feeding cannabis flower into a multi-chamber closed-loop extractor made specifically for use with CO2. When operational, supercritical CO2 enters the second chamber and effuses through the plant material like a gas while also dissolving the compounds in the plant like a liquid. As a result, every compound in the cannabis is extracted. To remove undesirable lipids and waxes, the extract is winterized, a process by which unwanted lipids, waxes, and other plant compounds are removed. The final extract is rich in phytocannabinoids and terpenes, with no traces of solvent left behind.
Pros
- Non-toxic and environmentally-friendly
- Moderate pricing
- No risk of residual solvents
Cons
- More expensive than some other extraction methods
- Less effective for retaining terpene content
- Requires extensive winterization to remove unwanted compounds
Hydrocarbon extraction
Hydrocarbons are solvents such as butane. They are used to make concentrates like BHO and certain live resins from fresh frozen cannabis flower.
Most manufacturers use a closed-loop extraction system similar to those employed by supercritical CO2 extractors. The cold, liquid solvent runs through the system and passes through the cannabis biomass, pulling phytocannabinoids, terpenes, and other plant compounds as it does so. The resulting mixture is collected in a chamber, where the hydrocarbon solvent is boiled off. This process, sometimes called recovering solvent, is critical for removing residual solvents from the extract. Since hydrocarbons have a low boiling point, these extracts retain more cannabis derived terpenes and phytocannabinoids.
Much like in CO2 extraction, the remaining extract contains significant amounts of lipids and waxes and will require post-processing and winterization.
Pros
- Effective at preserving terpenes and flavor
- Great for producing dabs like shatter, crumble, budder, and live resins
- Relatively inexpensive compared to supercritical CO2 extraction
Cons
- High pricing
- Extra steps need to be taken to remove residual solvents
- Requires winterization to remove unwanted compounds
Ethanol extraction
Ethanol is a highly polar alcohol used to strip away the cannabinoid- and terpene-rich trichomes (resin glands) from the plant material, making it a top choice for processing large volumes of flower at one time5. Ethanol extraction is also temperature agnostic, allowing professional extractors to work in hot or cold conditions without risking the quality of the final product. Cold ethanol extraction tends to be the more popular method given its ability to better preserve terpenes and reduce or eliminate the need for winterization.
In cold ethanol extraction, the process begins by chilling ethanol to temperatures as low as -40℃. This is necessary because, as a polar solvent, ethanol will also pull compounds like chlorophyll that reduce purity and impact flavor. Once chilled, the cannabis flower is soaked in ethanol, and the resulting solution is filtered to remove any remaining plant material that might have been pulled by the solvent. The ethanol then evaporates, leaving behind cannabis extract.
When cold ethanol extraction is used, the need for winterization may be eliminated altogether. However, if warm ethanol extraction is used, post-processing is required to remove unwanted compounds like lipids, wax, and chlorophyll.
Pros
- Cost-effective pricing
- The versatile solvent can be applied to a wide range of products
- Low toxicity reduces risks posed by residual solvents
Cons
- Additional processing is required to create the final product
- Evaporates at higher temperatures, risking terpene and phytocannabinoid content
Water extraction
Did you know that water can be used to create concentrates as well? Water, sometimes referred to as a solventless extract, is used to separate trichomes from the plant material and create high quality concentrates like ice water hash.
Water extraction is performed using cannabis flower that is fresh frozen, and sometimes cured, after harvest. This flower can be combined with ice-cold water4, which freezes the plant’s trichomes and makes it easy for them to break away from the flower. The now-loose trichomes float on the surface of the water.
Once the cannabis is thoroughly soaked, the resulting solution is filtered through extremely fine screens or micron bags to separate the trichomes from the water. Then, these trichomes are pressed into bricks or balls of hash- or kief-like material. After further refinement, the trichomes are pressed into hash bricks or patties and dried. The result is a high-quality hash product that still contains high levels of terpenes and phytocannabinoids, meaning the final product will be more potent, aromatic, and flavorful.
Pros
- Natural process
- Cold temperatures preserve terpene and phytocannabinoid content
- The final product is highly pure
Cons
- High pricing
- Not as efficient as other extraction methods, resulting in little product for a lot of effort
Which cannabis extract is right for you?
Whether you’re trying cannabis concentrates for the first time or are a long-time consumer, you have a diverse range of extraction methods and techniques to thank for the wide selection of cannabis concentrates on dispensary shelves. The end product you choose depends on your preference, cannabis consumption goals, and the cannabis consumption device you plan to use. For example, more pliable wax is best for use with a dab pen. Not sure how to choose? Ask an Ethos associate at your next dispensary visit, and check out our tips for getting started with concentrates.
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