Solventless or mechanical extraction methods involve a couple of different techniques that can vary based on the consistency and purity of the final product. From old-school scissor or finger hash to advanced rosin presses, there are many ways to separate cannabis resin from the trichomes without using any solvents. The most common forms of these extraction methods include hash, bubble hash, and rosin. 
Hash-making is the original form of mechanical extraction that separates the trichomes from the plant material. Original methods of hash making include rolling the plant between your hands until enough trichome heads are built up and collected or thrashing plants over screens and collecting the trichomes in a container. Traditionally, hash was formed into balls or patties because the outer layer helped preserve the trichomes and the resin within them. Suppose you’ve ever trimmed cannabis all day. In that case, the resin build-up on the scissors is technically a mechanical extraction method, producing the super (not) pure and sought after (kidding) product called scissor hash!
Bubble Hash:
As extraction techniques progressed, extractors realized that cold water and ice made the trichomes brittle and easily allowed them to separate from the plant material with a bit of agitation. Once the trichomes are separated, they are filtered and collected with various micron-sized bags. This extraction method produces a product called bubble hash. Although water is being used to make bubble hash, it’s not considered a solvent because the water does not dissolve the trichomes or the resin within. The trichomes are suspended in the water, separated much like oil and water.
The bubble hash is then dried and/or frozen, to remove the excess water.
Rosin:
One of the more modern extraction forms is with a rosin press. This process requires heat and pressure to be applied to raw cannabis flower, hash, or bubble hash, which breaks down the trichomes and releases the resin onto parchment. There isn’t enough heat to burn the plant material or hash during the press. Instead, there is just enough heat to warm up the resin, which melts out of the micro bags.
The purity of rosin is based on the starting material. Rosin made from flower will have a darker color and noticeable particulates from tiny fragments of plant material. Rosin made from bubble hash will be lighter in color and have minimal to no particles of plant material. Bubble hash-based rosin will also have a significantly higher cannabinoid percentage.
Flower Rosin:
Bubble Hash Rosin:
Rosin is consumption-ready immediately after a press, regardless of the starting material. However, there are various ways rosin can be cured or stretched and aerated to produce different textures, colors, and consistencies.
Rosin primarily contains THCA or CBDA since there isn’t enough heat to decarboxylate or activate the cannabinoids during the press. Therefore, to get the most out of rosin, it must be dabbed, smoked, or decarbed before making an infusion for edibles.
Many cannabis enthusiasts believe that solventless or mechanical extraction methods are the purest, safest, and healthiest extraction forms since no solvents or chemicals are needed. What about you? What do you think the best extraction method is? Share your thoughts in the comments below!
Special thanks to Johnathan M @botanichemist for providing photos!
