Houdini Lab

Concentrated Cannabis: A Reintroduction to Cold Water Extraction

Humans have relied on hash for spiritual and therapeutic purposes for millennia, according to archaeological evidence. In May 2020, the Journal of the Institute of Archaeology of Tel Aviv University revealed new evidence of hash use dating back to the Iron Age, which was discovered at the Judahite Shrine of Arad in Israel. The evidence dates back to the Iron Age.

Hash production has continued to be carried out using traditional methods, as it has for many thousands of years. This means that the hash-producing regions of the Himalayas or Morocco are likely to produce hash in a manner similar to that of the 8th-century hash discovered in Israel, namely, using a manual process. However, the emergence of legal cannabis marketplaces has ushered in a completely new era of innovation in the hash producing industry. One of these advanced procedures is cold water extraction, which is sometimes referred to as ice water extraction or cold water extraction in certain circles.


The use of freezing temperatures and agitation eliminates the need for toxic solvents, which have taken over the industry in the last few years. Ice water hash is being reintroduced by brands in order to produce the clean, pure, and solvent-free concentrates that their customers are now demanding. Coldwater extraction also contributes to the emerging trend of terpene-forward concentrates, such as live resin and High Terpene Full Spectrum Extractions, which are becoming increasingly popular.



Cold water extraction is based on the premise of pristine preservation of cannabinoids and terpenes, with no additional substances added to the process. With customers becoming increasingly wary of petro-chemical-based extraction procedures, it should come as no surprise that many manufacturers are turning back to cold water (or ice) extraction methods.


In his book “The Cannabis Revolution,” Ed Rosenthal, the pioneer of cannabis cultivation and extraction techniques, explains how cold water extracts are made from “water, ice, and agitation.” When exposed to these elements, the small trichomes that coat the flower’s surface become highly fragile and break easily. These trichomes break off into the ice water wash as the agitator is turned on. It is easy to collect trichomes since they are fat-soluble and may be collected with fine mesh bags. Once dried, the loose cannabis trichomes are formed into balls, bricks, or powdered kief-type items, which are then sold to consumers.


When it comes to coldwater extraction, as the name implies, it is a procedure that operates at or below the freezing point of water. This safeguards a much greater number of the most sensitive chemicals than would be achievable using conventional solvent extraction procedures.


Cold water extraction, in contrast to other extraction procedures, is easy and economical enough to be adopted by small-scale producers and growers. In recent years, however, as the commercial sector has begun to transition away from petrochemicals and toward more natural production standards, even commercial facilities such as CaliHash have began to employ cold water extraction techniques.


Cold water extraction, according to Calihash, “fundamentally preserves the integrity of the original cannabinoid profile.” High temperatures and pressure are frequently encountered during the majority of extraction procedures. The most volatile cannabinoids and terpenes are destroyed or altered under these intense circumstances. In other situations, the extraction is carried out at such high temperatures that the resulting product has a terpene profile that is almost non-existent.



In general, modern hash manufacturing for legal markets can be divided into two categories: solvent-based hash production and non-solvent-based hash production. During the last decade or two, solvent-based hash extractions have risen to become the dominant method of extraction. Concentrates such as butane honey oil (BHO), wax, shatters, and resins are now ubiquitous in most dispensaries, and they have become increasingly popular.


Butane, propane, ethanol, and CO2 are all used in solvent extractions. Producers combine cannabis flower (or trim) with the solvent of their choice in order to dissolve the important cannabinoids and terpenes present in the plant matter. The combination is subjected to high heat once it has been dissolved, in order to evaporate any leftover solvent, leaving behind a highly concentrated product. The texture, consistency, and terpene content of solvent-based extractions can differ significantly depending on a variety of parameters.


A well-extracted concentrate will have no detectable impurities from the manufacturing process in its composition. Nonetheless, there is a possibility that these compounds will end up in the BHO, wax, or shatter that the end customer purchases. To mitigate the hazards, all legitimate markets require some sort of testing for contamination prior to opening their doors. For the most common chemical pollutants such as pesticides, fertilizers, and solvents, each market has a separate set of permissible limits that must be adhered to.


The author of a 2019 paper for Environmental Health Perspectives, Nate Seltenrich, pointed out that many of the permitted levels were taken from those established for producers of herbal medicines and other medical items. These sectors, on the other hand, do not use butane or propane, which are the two most commonly used chemicals in cannabis extraction. Saltenrich notes that because there is no precedent to work from, “state regulators are left to their own devices,” which has resulted in a “vast variation of residue limitations for the solvents among lawful states.”


Finally, according to the Food and Drug Administration, several solvents may have tolerable limitations for consumption in certain circumstances. There are no test results available for inhalation, which would be the case if the substance were a cannabis concentrate. However, it is yet unclear whether there are any hazards connected with long-term exposure to cannabis concentrates that have been manufactured using solvents and retain residual solvents.


SOLVENT-BASED EXTRACTS are becoming increasingly unpalatable, and COLD WATER HASH is a viable alternative.

Many consumers are uncomfortable with the prospect of finding solvents in their cannabis, even though most state regulators have determined that they are safe and have set permissible limits for their presence in the plant. Consumers appear to prefer “pure” concentrated products over “potent” ones in this sector, as seen by the move from hot water extracts to cold water extracts in recent years.