Alcohol versus CO2 for CBD Extraction
By James Tindall, PhD
Cannabidiol (CBD) is generally produced by extraction from CBD-rich hemp plants. Extraction is the separation process for obtaining CBD’s, a valuable substance, from hemp/marijuana or almost any plant material. To perform the extraction, a solvent (usually liquid) is required.
The most used solvents for extraction from hemp plants is alcohol and extraction by super-critical carbon dioxide (CO2) but, there are also other solvents.
Alcohol versus CO2
There are some basic differences between these two solvents. First, alcohol has an origin in an organic material because fermentation of plants mostly produces it. The other solvent, CO2, is classified as a poisonous gas by the EPA such that 8-10% concentration of CO2 in the air causes nausea, unconsciousness and can cause death.
In general, alcohol extracts more substances from hemp plants than CO2 or, any other plants for that matter. Alcohol is a solvent made from plants for plants. Carbon dioxide extracts just non-polar chemical bonds, where alcohol extracts both polar and non-polar chemical bonds.
CBD from Alcohol Extraction is Better
As stated above, alcohol extraction provides more complex extracts from hemp and keeps the important terpenes and flavonoids intact. And this is important especially for hemp plants since they contain a very broad range of various substances – 113 compounds so far with more being discovered. It is particularly important for substances soluble in water, various oils, polysaccharides, acids and so on.
Water soluble substances are significant since the human organism is made from 70% of water and it makes these substances easier to absorb. In comparison, CO2 extraction misses many valuable compounds that are hidden in hemp, which alcohol extraction is successful in mining for the final product, which is of higher quality than the same product from CO2 extraction. However, CO2 extraction can be done at temperatures native to the plant, minimizing thermal degradation of the plant material and the extracted oils. This does make it a little better, but still inferior to alcohol extraction.
CBD Absorption
Another important aspect about alcohol extraction is the esterification of organic acids. Esterification happens when organic acids, CBD as an example, and other acid forms of cannabinoids react with alcohol. Produced esters are soluble in water, which makes the extract easier to absorb into the human body. This means that CBD extracted by alcohol has increased bioavailability and thus, greater medical potential.