The Science of Cannabis Extraction

Cannabis Plant

Why is cannabis extraction performed? Cannabis extraction can be performed for a variety of reasons, as well as in a variety of ways. The most widespread reason, of course, is to obtain potent extracts that can be used in the medical marijuana industry to treat patients dealing with a variety of illnesses and symptoms. On a more academic level, cannabis extractions are also performed purely for research purposes in an effort to understand the chemistry of the plant and make scientific inquiries into certain claims.


The Many Faces of Cannabis Extracts


Just as other compounds might be available in various solid or liquid forms, the effects of cannabis can be achieved in a variety of extract forms. The following is a list of just a few of the most common cannabis extracts:


  • Kief
  • A (usually) lower-quality extract made of the crystalline “trichomes” from the flowers of the cannabis plant. These are filtered out through screens and manual effort, producing a dry extract with a THC content anywhere from 20 to 60%.


  • Hash
  • A well-known solid-form extract comprised of pressed kief. This is often formed by first isolating the trichomes using solvents like ice water or ethanol to strip them from the plant. The kief must first be fully dried before it can be pressed into hash.


  • Butane Hash Oil (BHO)
  • A solid, brittle cannabis extract that is usually presented in the form of broken glass-like pieces “shatter.” The THC content is often very high—as much as 80-90%. BHO is a popular choice for the treatment of chronic pain.


  • Rick Simpson Oil (RSO)
  • This extract is considered a whole-plant oil and in the medical cannabis industry is generally administered orally or applied to the skin. This oil is produced from the buds of a female cannabis plant and contains various cannabinoids (THC, CBN, CBD, etc.) and terpenes.


    Cannabis Extraction

    Extraction Processes To turn the usual cannabis plant matter into these potent extracts, a number of different extraction and refinement processes have been developed over the years.


  • Winterizing
  • A process of removing fats and waxes from the cannabis plant by dissolving the plant extract in a liquid like ethanol. The mixture is then frozen at below-zero temperatures, and the waxes are removed by running it through a low-micron filter.


    This process is used to produce an optimally stable concentrate that will not become a buttery substance over time. When the fats are not removed, the product is considered a wax.


  • Distillation
  • Probably the most common technique, short path distillation exposes the cannabis oil to heat and vacuum in order to separate a variety of compounds from the extract (cannabinoids and terpenes, in particular).


    Using an appropriate laboratory setup, heat is first introduced to the extract to evaporate the cannabinoids and terpenes Then, the vapor enters a condenser tube, through which the cannabinoids travel and condense into the recipient flask. This final product does not need to be winterized, as the waxes and fats cannot vaporize and, therefore, remain in the first flask of unprocessed concentrate. This method generally produces the highest concentrations of cannabinoid molecules.


  • Live Resin Extraction
  • Most commonly, cannabis is dead and dried before it is processed. In live resin extraction, the live plant is frozen (such as with liquid nitrogen) right after it is harvested in order to perform extraction from a freshly-cut plant. A resin product is then created by using a closed-loop hydrocarbon extraction machine.


    This method of extraction generally gives a flavor that is more true to the original living plant but is also one of the most expensive methods to perform. Because most of the plant’s terpenes (essential oils) remain in the product, this makes it particularly popular on the market (and drives up prices).


  • Hash/Honey Oil Extraction
  • The production of Hash/Honey Oil (BHO + PHO) is also done via closed-loop extraction. In this case, the method involves a variety of stainless steel containers that essentially wash the cannabis with a solvent (often liquid butane or propane, which are considered liquid hydrocarbons).


    The cannabis is first washed with the liquid hydrocarbon solvent, then the first product is placed in a vacuum oven for the excess solvent to be removed. The second product is then poured out into a container where it will harden into a thin, toffee-like product known as “shatter.”


  • Supercritical CO2 Extraction
  • Carbon dioxide is considered a “supercritical fluid” that becomes a liquid under pressure. In extractions, CO2 leaves no residue, which makes it popular for use in extraction processes across a variety of industries. In this kind of cannabis extraction, supercritical CO2 is put into a pressurized container with the cannabis material. The mixture is then put through a filter to separate the CO2 from the cannabis and, when the pressure in the system is released, the CO2 evaporates back into a gas.


    Medical Marijuana

    Terpene Isolation Methods Terpenes are hydrocarbon oils that are responsible for fragrance in a variety of plants. A wide variety of plant essential oils—including those with pine or citrus scents—are comprised primarily of terpenes. In the case of cannabis, some experts believe that the terpenes of the plant are equally as responsible as THC for the high experienced during use (perhaps even more so).


    Common methods of terpene isolation from cannabis include the following:


  • Steam terpene distillation
  • This extraction method for the isolation of terpenes is considered a gentle method of extracting terpenes without risking their decomposition as a result of heat. Steam is introduced to the cannabis plant material in a distilling container, and the steam and oils rise up and move into a condenser. The essential oil and water then re-condense in the second container.


  • Cold trapping
  • This extraction method involves using a vacuum pumping system with a device known as a cold trap, which helps to remove contaminants. The system sublimates gas directly into a solid form, bypassing the liquid stage entirely. The product crystallizes in a sort of “frost” on the surface of the cold trap.


    Outfit Your Lab with the Right Furniture and Storage for Safe, Efficient Cannabis Extraction

    Whatever the reason your lab, company, or academic establishment is performing cannabis extractions, it’s important to make sure that all of your surfaces, equipment, and storage solutions are sufficient for your laboratory staff’s needs. Nothing makes performing high-quality work more difficult and frustrating than not having the space or tools necessary to complete tasks efficiently and properly.


    Don’t just combine the contents of various shelves to make space when it’s needed; make sure that all of your flasks, condensers, hydrocarbon solvents, and extract products can be stored safely by investing in updated stainless steel storage cabinets and casework from Genie Scientific. When using solvents for extractions, provide your laboratory staff with a quality Genie Scientific fume hood to keep employees safe and ensure product quality.


    To learn more about our high-quality lab furniture and storage options, browse our catalog or contact us at 714-545-1838.

    Watch Videos
    * Required