The solvent extraction is generally applicable for large-scale extraction. There are a great variety of commonly used solvents, such as ethanol, CO2, hydrocarbons. Why so many solvents used for extraction? The cannabis and hemp plant can produce more than 100 various terpenes, flavonoids, cannabinoids, which is extremely complicated. And each of these components requires different solvents and extraction methods.
Ethanol (Alcohol / Ethyl Alcohol) Extraction
In the process of ethanol extraction, the material is soaked in room or chilled temperature ethanol, which can draws out the terpenes and cannabinoids. Then the residual solvent can be removed by evaporation using heat and vacuum. It can obtain a crude extract. In order to get a purified CBD, CHC or other components, the crude extract can be further distilled and refined.
Ethanol is suitable for almost any type of botanical extraction, and it is even regarded as the safest and most effective solvent for extracting cannabis and hemp. Its benefits can be concluded as follows:
- It can be easily produced, safe and easy to operate.
- It possesses an affinity for cannabinoids at cold temperature.
- It can dissolve most polar as well as non-polar components.
- It can extract quickly as a kind of non-viscous liquid at atmospheric pressure.
- It can be efficiently recaptured and then separate the extracted components with a low boiling point.
- It doesn’t require dewaxing or winterization if done under cold conditions properly.
Carbon Dioxide (CO2) Extraction
The carbon dioxide (CO2) extraction includes the supercritical, subcritical, and mid-critical CO2 extraction. In the process of carbon dioxide (CO2) extraction, the CO2 is pressurized in order to pull CBD, THC and other cannabinoids from cannabis and hemp. Under certain temperatures and pressures, CO2 can function as a solvent, which can extract concentrates under high pressure and quite low temperature.
Compared to ethanol extraction, CO2 extraction needs more complicated equipment. But its product can be free of chlorophyll. It has other benefits as well.
- It is safe because of the non-inflammable, inert, and non-toxic properties of CO2.
- It can obtain a purer final product due to there is almost no residue after extraction compared to other solvents.
- It is an ideal solvent for temperature-sensitive materials because its critical temperature is close to room temperature.
Hydrocarbon Extraction (Propane, Butane, Hexene, etc.)
Hydrocarbon extraction generally uses butane as the main solvent. In the process of butane extraction, the cold liquid butane is released from the solvent tank into a column where contains the hemp or cannabis materials, which can dissolve terpenes and cannabinoids.
The hydrocarbon extraction has been more well-received over the last few years. There are several reasons:
- The hydrocarbon extraction equipment is more affordable than other solvent extraction equipment.
- It has a higher yield by utilizing hemp or cannabis plants more effectively.
- It can produce a great variety of final products with its versatility property.