Several methods and solvents have proven to be effective for extracting cannabinoids:

• Supercritical carbon dioxide
• Hydrocarbons, such as butane and/or propane
• Ethanol

Waxes and fatty acids from the plant material are also soluble in many of these solvents, and these materials must be removed during the refinement process. This is achieved through a process called winterization, which takes advantage of the different solubility of waxes and cannabinoids in a solvent.

Ethanol extractions have a solid and growing presence among the three most popular solvent-based cannabis extraction methods today. But because of its polarity, ethanol is notoriously capable of dragging water-soluble particles out of the cannabis plant during the extraction process.

Ethanol not only pulls out the desirable cannabinoids and terpenes, but also extracts the cell’s chlorophyll and plant waxes unless the ethanol is chilled to sub-zero temperatures. That is because the solubility of polar, water-based molecules in ethanol is directly correlated to the temperature of the solution.

We believe sub-zero ethanol extraction is a viable method for cannabis extraction which can be used to eliminate the winterization step. Experimental results show a 10-minute wash time at -40C with 190 proof ethanol extracts the majority of cannabinoids and few enough lipids to not require winterization.