Types of Extraction:
There are three main forms of cannabis extraction. We will highlight each type, briefly explain the processes involved in that product’s creation, and iterate a few key take aways for when considering quality of end product.
The first method of extraction is Butane Hash Oil (BHO). This method of extraction uses a nonpolar solvent (usually cold) to target and dissolve the essential oils in the cannabis plant matter. Then, the solvent is recovered for reuse and the remaining essential oils are harvested, post processed and then purged of residual solvents. The process inherently needs to be done at cold temperatures to avoid extracting undesirable components in the plant (i.e., chlorophyll, phospholipids, color pigments). The essential oils contained in the cannabis plant should have a slight yellow hue if grown and stored properly. If stored in optimally then the oils will begin the oxidation process and turn amber. To capture the broadest profile of both cannabinoids and terpenoids the biomass should be extracted as fresh as possible.
I digress, my apologies we have a lot to cover and this is just one of the many to come blog posts PROOK will release.
The second method and presumably the largest scale form of cannabis extraction, Ethanol. This is a much less selective process compared to BHO or the third method of extraction. This is yet another form of solvent extraction that uses the semi-polar ethanol (or alcohol) molecule to target the essential oils in the biomass. Ethanol seeming like a less risky way to make extracts (this can be misleading with how flammable and how hot ethanol gets, but also for another time). Ethanol has a very low vapor pressure at atmospheric temperature and pressure. This allows for systems to process greater amounts of cannabis in shorter periods in time. The catch, well along with fast cycle times, large batches you also extract more undesirables. These components can be decreased by cooling the ethanol off (this being a general chemical trend; colder solvent can dissolve less solute than a warm solvent). Even though some control with temperature there will be a larger presence of impurities causing the final product of this extraction being called crude oil (or FECO, RSO, Full spectrum extract). This crude oil is potentially one of the most medicinal. This really has more influential factors into what is considered the “most medicinal”. For another time that conversation can be saved… There is a fork in the process pipeline at this juncture. You can stop and have the crude FECO or you can take purification to a more extreme and distill the oil. Using vacuum (negative pressure) and temperature on a device called a wiped film evaporator (WFE). This device is precisely controlling the vacuum and temperature as the oil is smeared in a microns thin layer and specific compounds are evaporated and recondensed in a different spot resulting in the most selective process resulting in the highest purity oil out of any extraction method.
The third method of harvesting all the golden nectar from these magical plants is Solventless extraction. This being the field we are most freshly entering. There are many variable in using water (both liquid and ice) not as a solvent but as a carrier for the delicate trichome heads as the slurry is poured through a series of micron filters each stepping the purity to the next level by allowing less undesirables through at each stage of the filtering process. The water, ice, biomass bath will be agitated to knock the oil glands off the plant and then pass through the aforementioned micron filters. Then the sandy consistency mix is added to trays and placed into a freeze dryer where the remaining water is removed. The now dry bubble hash will then be placed into small micron bags and placed on a heated press where the oils are gently heated and liquified and then filtered through the bag as they make their way out of the press as a product referred to as hash rosin.
In conclusion, these are really just three of the main ways cannabis is extracted commercially. There are many other types and we did not cover here but will address upon request or in the future at some point. We hope you enjoyed reading and maybe learned some neat facts and lingo regarding cannabis concentrates and the extraction process. We are all about transparency and will try and produce good information to be used a reliable source of current cannabis knowledge.