Understanding Extraction Methods
Cannabis concentrate is extracted either from the flower or from the trimmings of the cannabis bud before it is sold as buds. There are several ways to extract and/or refine cannabis to produce a variety of textures. This blog piece will explore some of those extraction methods. Depending on which generation you belong to, you have heard about different products. For example, my generation grew up hearing about Hash products. The origin is debatable, but according to Wikipedia and other sources, “Hashish has been consumed for many centuries, though there is no clear evidence as to its first appearance. North India and Nepal have a long social tradition in the production of hashish, known locally as charas. In 1596, Dutchman Jan Huyghen van Linschoten spent three pages on “Bangue” (bhang) in his historic work documenting his journeys in the East. He particularly mentioned Egyptian hashish.”
Dry Sifting
The most common form of manufacturing in the early days was traditionally done by pressing or rubbing the flowering plant between two hands, then forming the sticky resins into a small ball of hashish called charas. This method is still used today in some parts of the world.
Another separation process uses a mechanical tumbler to separate the trichomes from the dried flower. This process is known as dry sifting and the result is a powder known as Keif or drysift. Sometimes the “mechanical” process is done by filling a cheesecloth bag with flower and hitting it with a stick, then collecting the keif from below the bag.
Keif can have an extremely high percentage of THC because there is no plant material in the final product. It is perfect to spread over the top of a tasty cannabis flower strain to increase the potency of your smoke. A note for the THC percentage chasers: If you enjoy the taste of lower percentage flowers like Tangies, but want the kick of higher THC flowers, this might be the best way to consume your product. It may also be a way to make your flower last longer because of the high potency topping.
Ice Water Hash
Another extraction method is Ice Water Extraction or Solventless. To create ice water hash, multiple bags are stacked together in a tub of ice-cold water, or the flower is placed in a tumbler (similar to a washing machine) and the bud is thoroughly mixed in the ice water bath. This freezes the trichomes and allows them to break off cleanly. When the mixing process is complete, the water is drained from the bottom into stacked bags that have different sized screens. The trichomes sift through the screens, resulting in several layers depending on the size of the filtering screens. In most cases, lighter colors are sold or used as smoking products. Darker colors contain more plant material and are used to make edibles.
Refining processes, including this one, increase the percentage of THC substantially because they create a concentrated form. In some states, there has been a recent increase in further refinement of this process. An added step known as pressing increases the THC percentage even more. After the ice water hash has dried, it is put into a cheesecloth bag and placed in a heated press under high pressure. Depending on the heat of the press, the result is a slightly liquified product that maintains the full spectrum of flavor, terpenes, and other cannabis compounds with a much higher percentage of THC. It is a dab-able vaporizing form of concentrated cannabis.
BHO and CO2 Extraction
In today’s market, these are the two most common types of cannabis extraction for a variey of cannabis concentrate products with wide-ranging textures and consistencies. The consistency and texture of the final product (shatter, wax, crumble, etc.) depends on the finishing methods. It can be “whipped” to form a wax or batter-type consistency, or it can be allowed to harden like glass to form a “shatter”.
CO2 extraction is also known as Supercritical CO2 Extraction. Cannabis flower or trim product is added to a closed loop system along with a CO2 solvent that acts like a gas and completely fills the extraction tube. The CO2 retains a liquid-like consistency that is powerful enough to wash away cannabinoids and terpene compounds. The Supercritical CO2 fluid can be passed over the raw material to strip away the valuable resinous trichomes. This method is favored by some because it is affordable, non-toxic and eco-friendly. In spite of these selling points, CO2 extraction requires time-intensive post-processing to create a pure product as compared to butane hash oil (BHO) equipment that eliminates the risk of leaving behind residual solvents in the finished product and is done in a shorter time frame.
BHO extraction is losing the stigma associated with the process and is now one of the most widely used processes in the industry. Hydrocarbon extraction uses hydrocarbons such as butane or propane to dissolve hemp’s trichomes. “BHO extractions use engineering peer-reviewed equipment in a Class 1, Division 1 environment that meets the most rigorous standards from the American Society of Mechanical Engineers and the American Petroleum Institute,” according to UNA Technologies, an extraction equipment manufacturer. “One of the most exciting and innovative features afforded by BHO extraction is the ability to reap a larger concentration of terpenes and other minor compounds. CO2 extraction methods can be efficient at crafting an odorless and tasteless cannabis distillate, but so can BHO. In addition, BHO extraction enables manufacturers to produce high-cannabinoid and high terpene full spectrum extracts.” This a commonly known characteristic of BHO extraction and the reason it is so widely popular in the industry.
In summary, the product is a matter of the consumer’s personal preference. In Massachusetts, we are seeing more solventless extractors coming online to keep up with the demand in neighboring states. This author is pleased that more of that product will be coming to the MA market in the next six months or so.
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Article written June 11th, 2021.