CO2 CBD extraction process is a popular method for producing high-quality cannabis oil rich in cannabidiol (CBD). This process is favored in the medical cannabis and therapeutic hemp industries for its safety, environmental friendliness, and ability to produce a consistent, high-quality product.

CO2 – A Safer, Cheaper, Greener Solvent

CO2 extraction uses carbon dioxide to extract cannabis oil, offering numerous advantages over traditional solvent-based methods like hexane or butane. CO2 is non-toxic, environmentally friendly, and less flammable, making it safer and cleaner. It also results in a more palatable final product.

What Is Supercritical Carbon Dioxide (ScCO2)?

At standard temperature and pressure, CO2 is a gas. It becomes a liquid at 60.4 psi and a solid (dry ice) at -78°C at standard pressure. When heated above 31.10°C and pressurized to 1,071 psi or higher, CO2 enters a supercritical state where it has properties of both a gas and a liquid, making it an excellent solvent for extracting cannabis oil.

Supercritical CO2 Cannabis Oil Extraction Process

1. Preparation: Ground cannabis or hemp material (trim) is placed in an extractor chamber.
2. Extraction: Pressurized CO2 gas at the optimal temperature (ScCO2) is pumped into the extractor chamber.
3. Interaction: The supercritical CO2 dissolves the cannabinoid compounds in the cannabis.
4. Separation: The CO2 carrying the dissolved cannabis oil passes through a pressure release valve into a cyclonic separator.
5. Collection: In the separator, CO2 separates from the cannabis oil. The CO2 is recycled back into the system, and the oil, waxes, and resins are collected in a vessel.

Equipment Costs

Supercritical CO2 extraction equipment is expensive, ranging from tens of thousands to hundreds of thousands of dollars, depending on capacity and features. Despite the high initial cost, it is comparable to other solvent-based methods when considering safety and regulatory compliance.

Supercritical vs. Subcritical CO2 Extraction

Supercritical CO2 Extraction:

• Operates at higher temperatures and pressures.
• Produces a peanut butter-like substance rich in CBD.
• Requires additional processing (winterization) to remove fats and waxes.
• Kills bacteria, mold, and contaminants.
• Efficiently extracts more CBD in a shorter time.

Subcritical CO2 Extraction:

• Operates at lower temperatures and pressures.
• Produces a molasses-like substance preserving more cannabinoids.
• May be more suitable for applications needing a broader cannabinoid profile.
• Slower process compared to supercritical.

Winterization Process

Winterization is used to refine supercritical CO2 extract:

1. Mixing: The extract is mixed with ethanol.
2. Freezing: The mixture is placed in a freezer for 24 hours to crystallize fats and waxes.
3. Filtering: The mixture is filtered to remove crystallized fats and waxes.
4. Evaporation: The ethanol is evaporated, leaving behind pure CBD oil.

Cannabidiol Oil Yields

The ScCO2 method typically yields about 10% “true” cannabis oil based on the trim weight. Including resins and waxes, the yield can

be between 17-25%.

Choosing Between Supercritical and Subcritical Extraction

The best extraction method depends on the desired end product and application.

Supercritical CO2 Extraction:

• Advantages:
  • Higher yields of CBD.
  • Faster process.
  • Effective in killing bacteria, mold, and other contaminants.
  • Produces a purer product after winterization.
  • Can be tuned for different compounds through fractionation.
• Disadvantages:
  • Higher initial equipment cost.
  • More complex process requiring precise control over temperature and pressure.

Subcritical CO2 Extraction:

• Advantages:
  • Preserves a wider range of cannabinoids and terpenes.
  • May produce a more “full-spectrum” extract.
  • Lower temperatures and pressures can be gentler on compounds.
• Disadvantages:
  • Lower yield of CBD.
  • Longer extraction times.
  • May require more processing steps depending on the desired final product.

Conclusion

Both supercritical and subcritical CO2 extraction methods have their own advantages and are suitable for different applications. Supercritical extraction is favored for high-CBD extracts, particularly where purity and yield are critical, while subcritical extraction might be preferable for products requiring a broader cannabinoid profile. Investing in supercritical CO2 extraction equipment offers the flexibility to perform both types of extraction, allowing producers to adapt to various market needs and product specifications.