Many cannabis extract consumers may be wondering what the difference is between extracts made with hydrocarbons, like butane, and those made with supercritical CO2 extraction. Let’s take a brief look under the hood of these two extraction methods and see what the differences really are…
First up is hydrocarbon extraction. When hydrocarbons like butane are used, they soak the plant material in liquid butane for a number of minutes. The butane chemically puts a range of plant materials into solution and extracts them all at once. Fortunately, chlorophyll and other plant compounds that would ruin the extraction are not as readily soluble in hydrocarbons and if the extraction is carefully timed, few of these compounds make it into the final extract.
What does make it into some final extracts though, is part of a larger problem inherent to hydrocarbons. Butane is both poisonous and explosive, so it’s nasty stuff to work with. To legally do butane extractions, a Class 1 Explosion Proof Room is required. While these protective rooms can help prevent some level of property damage to the surrounding structure – they don’t do anything to protect the people inside the room. A number of people die from butane based explosions every year and others are overcome with the gas and have to be hospitalized. And while you would hope that is the end of the story, it’s not.
If extracts are not properly processed and evacuated of all butane, residual butane can remain. The serious problem with residual butane is when it is heated to 900 degrees (something that can happen with modern “dab rigs”), it forms benzene. And benzene is extremely hazardous, even in small quantities. Unfortunately, benzene isn’t the only possible hazard. Butane is an excellent solvent for cannabis, but it is also an excellent solvent for other things, such as machine and valve oil. The types of things you find in tanks that have been used over and over again and serviced. This oil readily dissolves in butane and then is left as a residual in the cannabis extract when the butane is removed. All of these residual compounds can end up spelling trouble for someone’s health. There must be a better way than this. That is where supercritical CO2 extraction comes in.
CO2 extractions use CO2 as a non-polar solvent to dissolve the fats and oils accumulated in the cannabis plant. And CO2 extractions are highly selective. CO2 is also non-toxic to the point we load our soft drinks with it. CO2 also cannot exist in any form but a gas at 1 atmosphere of pressure, so it leaves behind a very pure extraction when returned to normal pressures. Even if CO2 did leave a residual, it would be non-toxic. CO2 is not flammable at all, in fact, you could extinguish a butane fire with CO2.
At various pressures and temperatures, CO2 will selectively dissolve waxes, terpenes, and cannabinoids. These elements can then be processed individually, or selectively recombined to form a wide variety of products. The products produced are very pure and never contain a toxin risk.
However, CO2 is not without its drawbacks. The processing time needed to produce a CO2 extraction is much longer than butane. This is because a larger amount of solvent is needed and current flow rates limit how much solvent passes over material in any given minute. As a result, CO2 extraction products can be a little more expensive.
However, for those interested in being as healthy as possible when consuming cannabis concentrates, the clear choice is CO2 extraction. It is for these very reasons we only teach supercritical CO2 extraction at UCANNTECH, we do not teach hydrocarbon extraction. We believe any encounter with cannabis should be a healthy one.