The various extract types are defined so there can be some consensus once and for all.
Advancement in extraction technology, blossoming product innovation, and state legalization continues to expand in the cannabis and hemp industry. With all that, there has been an ever evolving and growing list of concentrate product types. In this article, the various extract types will be defined so there can be some consensus once and for all.
The cannabis industry is still relatively young, but that has not stunted the development of innovative extraction technologies and cannabis product types. In hyper-competitive markets—such as California, Colorado, and Washington—manufacturers are competing on price or novelty. While most consumers favor low prices, as in any industry, there is a strong and growing market for super premium novelty products. This is especially prevalent in the concentrates category.
As covered in the solventless extracts overview in March (1), cannabis concentrates have historically been available for a long time. The first method of producing concentrates was hash production, where trichomes are separated from the plant and collected. Now, there are many more methods of extraction which produce many different extract types. Each extract type has a different viscosity, color, flavor profile, and can even have a different chemical composition. These differences are based on the extraction solvent, extraction method, source material, and other factors. Below is a list of extraction methods and extraction solvents that are commonly used in the cannabis industry today.
Extraction methods and solvent types produce relatively different outcomes, especially with respect to the viscosity of the extract. Each process extracts a different matrix of compounds as a result of solvent polarity, solvent density, quality of plant material, and others. Solvent extraction can be done using polar solvents (such as ethanol), or nonpolar solvents (like CO2 and butane). Ethanol is an incredibly efficient solvent and easily extracts both tetrahydrocannabinol (THC) and tetrahydrocannabinolic acid (THCA) at a wide range of temperatures. Most cannabinoids and terpenes, such as THC or limonene, are nonpolar. Hydrocarbon solvents and CO2 are both nonpolar, so they make excellent choices for extraction solvents. However, THCA is polar and, therefore, less soluble in nonpolar solvents than THC.
The viscosity of cannabis extract is an effect of the concentration of terpenes, cannabinoids, waxes, and other compounds that individually have a wide range of viscosities. At room temperature, atmospheric pressure, and in its pure form:
Terpenes are a volatile liquid and many of them act as solvents. So, an extract with a relatively high concentration of terpenes will be a liquid. If an extract has a high concentration of THCA, the extract will likely be a solid or have crystalline formations in the extract. If there is a high concentration of plant waxes, the extract will likely be a solid or have a very high viscosity.
The cannabis plant naturally produces THCA. However, during the drying and curing or if cannabis ages without proper storage, some of the THCA can turn into THC. Terpenes will also change during the drying and curing process because of oxidation, evaporation, and the plant’s enzymes continuing to react and produce different terpenes. So, a freshly harvested cannabis flower will have a different chemical profile than that same flower after it has been dried and cured. In the past few years, many operators have produced cannabis extract using freshly harvested cannabis flower to create an extract with a very different chemical profile. After harvest, the cannabis flower is quickly packed and frozen to preserve its chemical profile and trichome structure. The result is live resin, an extract with a terpene and cannabinoid profile of the freshly harvested cannabis flower. Live resin can be produced with many different extraction methods, but it is most commonly produced through hydrocarbon extraction and ice water hash.
Ice water hash is a method intended to physically separate the trichomes from the cannabis flower by suspending and then agitating the cannabis flower in a bath of ice and water. The interaction with the ice, physically knocks the trichomes off of the cannabis flower and they end up in the cold water. The mix of water, ice, cannabis flower, and trichomes is then filtered through mesh screens or bags with progressively smaller pore sizes until all trichomes have been collected. These trichomes are collectively called hash and can be further processed in many ways to produce extracts of different compositions and viscosities.
In summary, different types of extracts come from different extraction methods, source cannabis material, and any further processing that is done after the extraction. There is no governing body to standardize nomenclature around methods or extract types. Innovation in cannabis extraction technology, extract refinement, and method of administration spaces are all continuing to happen at a fast pace. Until there is official authority around naming conventions, leaders in the cannabis industry are taking responsibility for standardizing language around the wide variety of products that are on the market today.
Some common terms and definitions include:
Lo Friesen is the founder, CEO, and Chief Extractor of Heylo. With a background in chemistry and clinical research, Lo was inspired to explore cannabis as a medicine and to enter the emerging industry. She joined Eden Labs, a leading CO2 extraction equipment manufacturer to support and expand a Research and Development department. There she managed the development of their latest and greatest CO2 extraction system. In 2017, after working with Eden Labs and another cannabis processor, Lo launched Heylo with a mission to help people get more out of life with cannabis.
L. Friesen, Cannabis Science and Technology® Vol. 5(6), 14-15 (2022).