Extraction 101—Which Solvent Is Right For My Business
Businesses have more options than ever when it comes to creating potent cannabis concentrates. The modern advancements in extraction techniques allow for manufacturers to not only create purer, more desirable products but also exponentially scale up production.
When starting off in the cannabis extract industry or when adding an extraction wing to your current cannabis cultivation operation, it’s critical for business owners to select the proper solvent that fits their unique needs. While this may seem overwhelming at first, acquiring a deeper understanding of the pros and cons of current popular solvent options can help to simplify the decision.
The Ultimate Goals Of the Extraction Process
Regardless of the solvent, every extraction run will have the same fundamental goals. The first of which is developing a high-quality product. Maintaining terpene integrity and maximizing cannabinoid percentages make a particular concentrate more desirable to customers and demand a higher price point.
Manufacturers will also have a keen interest in enlarging yields. It’s essential for an extract business of any size to get the highest returns possible when running their plant material through an extraction system. Otherwise, overall profits will take a hit.
Finally, extraction techs have efficiency to consider. How will the processes involved with a particular solvent scale with the business? While smaller operations and artisanal brands have the luxury of sacrificing efficiency for quality, companies with larger-scale production models will need a solvent that can efficiently produce mass quantities of cannabis extracts.
What Is CO2?
Carbon dioxide (CO2) is one the most abundant molecules on the planet, and it’s also a popular solvent used in cannabis extraction. As you know, when CO2 naturally takes the form of a gas. However, in order to use the molecule as a solvent, it’s first rendered into a supercritical state by exposing the CO2 to extremely high temperatures and pressure. While in the supercritical semi-liquid state, the CO2 can be used to separate the cannabinoid-rich resin used in extracts from the cannabis flower.
Supercritical CO2 extraction has been around for decades in industries like coffee and food extracts, so when concentrates took off in popularity, they seemed a natural fit for cannabis. While CO2 is considered a cleaner solvent compared to hydrocarbons like butane or propane, it has some clear disadvantages.
CO2 requires a tremendous amount of pressure to maintain a semi-liquid state, sometimes up to 5,000 PSI. Engineering a machine capable of reliably withstanding such pressures is no easy feat and can be quite expensive. Many small to mid-sized extraction operations find that the startup costs involved in investing in CO2 extraction just aren’t feasible.
This high pressure also directly impacts the quality of the extract, as it damages the terpenes and flavonoids during the extraction process, resulting in a sub-par product in terms of overall flavor and therapeutic benefit.
The hydrocarbons—BHO and PHO
Hydrocarbons are quickly becoming some of the preferred solvents in the cannabis extraction industry. In particular, butane (BHO) and propane (PHO) have garnered a reputation for creating extremely high-quality THC oil and other concentrates.
Butane and propane are both nonpolar solvents with low boiling points, making them excellent at isolating trichomes from the rest of the vegetal material in cannabis flower with only a fraction of the pressure required for supercritical CO2 extraction. The result is a final product that more closely resembles the plant it originated from, as substantially more of the terpenes remain intact.
Unlike supercritical CO2 extraction, hydrocarbon extracts don’t require further time-consuming processing like winterization and fractional distillation once the butane or propane has been vacuum-purged, making it a significantly more efficient option.
However, with hydrocarbons, safety is of paramount importance. Both butane and propane are highly flammable gases and can be potentially hazardous if used incorrectly. When hydrocarbon extraction is conducted by untrained individuals using DIY methods like open blasting, the process can be extremely dangerous. Commercial manufacturers will need to invest in a closed-loop system and a class one division one explosion-proof room in which to house the system. Typically, this is still less expensive than supercritical CO2 extraction systems.
Ethanol, more commonly known as alcohol, is another common solvent used in CBD and THC extraction. Unlike the hydrocarbons BHO and PHO, ethanol has a positive molecular charge, making it a polar solvent. This means that it will bind not only to the active compounds like cannabinoids and terpenes but also to other water-soluble compounds present in the cannabis material. This includes things like lipids, waxes, and chlorophyll which can contaminate the final product, making for an extract with a harsh or unpleasant flavor.
One way for extractors to avoid this problem is by chilling the ethanol to below -40 degrees Fahrenheit, preventing the solvent from adhering to the unwanted compounds. Unfortunately, even with supercooled conditions, ethanol extractions will never attain the same purity and quality of hydrocarbon without expensive and laborious further processing. Because of this lowered purity, ethanol can’t be used to make top-shelf THC extracts like shatter or crystalline.
Where ethanol begins to outshine the competition is with its efficiency and affordability. Not only are baseline costs for ethanol extraction equipment significantly lower than hydrocarbons and CO2, but due to low electrical and labor costs ethanol offers the highest throughput. For large manufacturers processing thousands of pounds of biomass a day or operations that want to allocate more of their financial resources to growing cannabis itself, ethanol can be an ideal THC extraction method.
There are various ways to cultivate cannabis. The best method will be highly dependent upon capacity and the selection of solvent and machinery.