What is a solvent?
A solvent is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature.
The main solvents used in cannabis extraction are carbon dioxide, butane, and ethanol. Most extracts are vaporized, via a vape pen or by dabbing, but they can also be incorporated into edibles. Extracts can also be smoked by topping a bowl with wax or dipping a joint in concentrate however this is far less common. At the consumer level, retailers more than ever now are labeling their concentrates by extraction method, detailing whether or not solvents were used and to what extent.
Carbon Dioxide is fairly new to cannabis concentrate processing, however this process has been around since the late 60’s early 70’s and has been used in beer making extracting essential oils and more. However today, the use of CO2 for cannabis extraction is quickly positioning itself to be one of the leading technologies for industrial hash oil production.
Butane offers a relatively simple and inexpensive method to extract a large percentage of THC and other desirable compounds from cannabis . There has been a lot of controversy when it comes to what is considered a safe amount. The argument is that long term consumption of butane has not been studied enough to say if it is safe at all. Using butane as the extraction solvent creates what is known as butane hash oil. The process starts with cannabis and liquid butane in a pressurized and heated system. By using evaporation under a vacuum, it is then possible to remove the butane solvent. The vacuum turns the butane from liquid to a vapor, making it easier to remove.
This kind of extract is also known as shatter, which is a clear material that typically includes cannabinoids like THC, CBD and other chemical components, including terpenes.
Several common forms of cannabis extraction rely on a solvent, such as alcohol. In brief, the cannabis soaks in alcohol, usually ethanol, the plant material is then removed, the liquid filtered, and the alcohol is removed with some form of evaporation. One of the biggest challenges with ethanol is its property to mix with water and dissolve molecules like chlorophyll. Removing the chlorophyll from the extract is important as it produces an undesirable, bitter flavor.
Vitamin E Acetate
This was the most infamous as of January 2020 the CDC reported 2,602 confirmed and probable cases in all 50 states of severe acute respiratory distress syndrome associated with a recently inhaled drug aerosol . As many as 57 people died across 27 states.
The culprit ended up being illegal vape carts with Vitamin E Acetate used as an additive or thickening agent. This man-made mass poisoning event is akin to bathtub gin under alcohol prohibition. This marks a significant talking point for federal legalization for both medical and recreational cannabis use.