Supercritial Fluid Extraction Explained
Supercritial Fluid Extraction Explained
The supercritical fluid extraction (SFE) process allows for the extraction of very pure, high-value product from materials which otherwise would be considered by-products or waste and sold cheaply, or simply disposed of.
Traditional extraction methods lack the efficiency associated with SFE (using CO2) and normally involve the use of chemical solvents which can create adverse environmental impacts, can affect the quality of the extracted material, and must be carefully used, stored and disposed of.
“Decarboxylation” is a long word for a simple process. To decarboxylate your herb, you just need to heat it. Applying a little heat to dried bud inspires some fascinating chemical reactions in the plant. Namely, you transform compounds called cannabinoid acids into a form that is readily usable by the body.
Cannabinoids are chemicals found in the cannabis plant that bind to cells in the body to produce effects. Sometimes decarboxylation is called “activating” or “decarbing”.
You probably have already heard that the primary psychoactive compound in cannabis is delta9-tetrahydrocannabinol (THC). THC is what gets you high when you smoke a little flower or eat an edible. But, you won’t find much THC on a live, growing marijuana plant, if any at all. What you find instead is another compound called THCA, which is short for tetrahydrocannabinol acid.
THCA is not psychoactive. That’s right, this acid compound won’t get you high. In order to feel the mind-altering effects of cannabis, you need to transform THCA into psychoactive THC. So, you apply a little heat.
Each time you take a lighter to a joint or place your cannabis in the oven, you are acting the part of an amateur chemist. You are converting one compound into another. You’re turning an otherwise non-psychoactive plant into a psychoactive one. To get specific, you are removing a “carboxyl group” from the acid form of THC. Hence the term “De-carboxylation“. Without that carboxyl group, THC is able to freely bind to cell receptors in your brain and body.
Winterization, also known as alcohol wash, is done after the initial extraction procedure, which can use CO2, nitrogen, butane or other solvents. All these lead to the separation of cannabinoids and terpenes from the cannabis plant and produce minimally unwanted substances, like plant waxes, fats, and chlorophyll.
When CO2 is used for the initial step, the raw extract is placed in ethanol, then heated and finally frozen to filter out the undesirable by-products. The ethanol solution is warmed to approximately 120 degrees F, and it’s not frozen until all the solvent has evaporated. For proper winterization, the solution should be frozen for at least 24 hours at a minimum temperature of 32 degrees F, or for 48 hours at 13-5 degrees F.
After this step, the alcohol solution needs to be filtered for removing the waxes. The extraction and refinement steps can be repeated several times until a pure oil is obtained. Now, please note that it’s possible for the final product, which is dark in color and has a maple syrup-like consistency, to have a green tint.
The green hues are given by chlorophyll and can be removed through various methods, such as washing the extract with ethanol tincture or exposing it to sunlight or UV radiation. While these procedures can remove the chlorophyll, in most cases a part of the cannabinoids are also destroyed; this happens at a slower rate, but it still affects the final concentration of cannabinoids.
For de-waxing, your solvent, in this case, is probably butane. Also called single-solvent de-waxing, this process uses only butane. You run butane through the plant material to extract it, and then bring it down to sub-zero temperatures so the lipid material separates out. Then you would put it through a Büchner funnel, and attach it to a passive vacuum. The undesirables sit in the top layer. You have to be able to pull the butane through fast enough without having too much evaporation. Butane needs to be pulled through fast enough to be able to separate the layers, and left behind are the plant fats separated from the oils. It’s almost the same thing as winterizing, but not as efficient, but it doesn’t harm your terpenes as much compared to the alcohol.