There has been a huge resurgence in demand for solventless cannabis concentrates in the past few years. This is predominantly due to advancements in technology that have given producers the ability to manufacture hash without using chemical agents.
In this article, we’ll discuss the difference between solvent and solventless extraction methods and how technology is restoring the time-tested tradition of solventless hash.
Solvent Methods
Long before the rise of shatter, wax and live resin, hash was the most widely used form of cannabis concentrate. Most modern day concentrate manufacturers are opting to use solvent based extraction to expedite processing times.
Butane Hash Oil, more commonly known as BHO, is currently the leading form of cannabis extraction in the concentrate market. Using this technique producers are able to make a range of products including shatter, crumble, glass, wax, and sap. However there are some major drawbacks to this method of extraction.
Butane is an incredibly explosive and unstable chemical that if used improperly can result in significant damage to manufacturing machines or loss of life. Another danger in using butane to extract is the risk of residual chemicals that can be extremely harmful to the user’s health.
CO2 extraction is much safer and healthier than BHO, however, the equipment required to extract using CO2 is extremely expensive. Extraction is only accomplished using carbon dioxide and very high pressure, this process is known as supercritical fluid extraction. SFE allows the CO2 to permeate the trichomes extracting every last ounce of oil.
Pressed Hash
There is a growing movement of concentrate producers who are committed to making solventless cannabis extracts. While ancient methods of producing hash are certainly solventless, advances in technology have given manufacturers the ability to increase production turn around.
The development of rosin and hash presses have been a driving force behind this solventless revolution. The final product in this method of extraction is never exposed to any chemicals. Instead, hot and cold temperatures combined with the mechanical press are able to manufacture a terpin rich extract.
First, let’s cover pressed hash. There are a couple of techniques, namely dry sift and dry ice, that can create a beautiful hash brick. Dry sifting involves breaking up cured and frozen plant material on a very fine screen. The trichomes will separate from the flower and be filtered through the screen creating a high quality kief.
The dry ice technique combines large chunks of dry ice and frozen plant material in a porous bag that filters the kief upon shaking. However due to the vigorous nature of this method some plant material can seep through reducing the quality of the kief.
Once all the kief has been collected, it is placed in a hydraulic press to form the hash brick. The higher quality the kief, the better the hash.
Pressed Rosin
Creating solventless rosin uses three main methods of extraction, the bubble or water method, dry-sift, and raw plant material. The bubble method soaks marijuana flower in ice water which is then strained through a series of filters. The end product must then be dried before placing into the rosin press.
Some manufacturers opt to use the raw plant material although you can again expect a much lower yield percentage. Dry-sift is a bit more effective as it not only produces a high quality rosin but also a greater yield.
Whether you use the bubble method, dry sift, or raw flower, the two factors that are essential to rosin manufacturing are heat and pressure. Higher temperatures typically produce better quality rosin that is full-melt, meaning perfect for dabbing.
Freeze Dryer
While freeze dryers are not necessarily a new invention, their use in the cannabis extract industry is a fairly new development. They use a process called Lyophilization, where moisture is removed from hash by exposing it to subzero temperatures and then warming it a vacuum environment. This dries the rosin making it safe for consumption.
While there are consumer grade freeze driers on the retail market, large extraction companies use scientific grade freeze driers that provide more control of the freezing and warming cycles.