Ethanol extraction — full-spectrum at scale

TL;DR

• Ethanol (99 %) dissolves polar and non-polar cannabinoids.
• Cold ethanol (−40 °C) minimizes wax & chlorophyll pickup.
• Ideal for full-spectrum tinctures and RSO (Rick Simpson Oil).
• Rotary evaporator fully removes ethanol (residuals <10 ppm).

Cold vs warm

Cold ethanol extraction (–40 to –80 °C) is today's standard: low temperature prevents chlorophyll and wax extraction, eliminating winterization.

Warm extraction is cheaper but yields green, bitter oils requiring extra purification steps.

Process steps of solvent recovery and refinement

After the actual extraction, a mixture of ethanol and the dissolved plant substances is obtained. In order to separate the solvent from the crude extract, rotary evaporators or falling film evaporators are used in the industry. Under vacuum, the boiling point of the ethanol is drastically lowered, which minimises the thermal stress on the temperature-sensitive cannabinoids. This step is crucial for the economic efficiency of production, as the vaporised ethanol is condensed, collected, and can be reused in a closed loop to a very high percentage for subsequent extraction cycles.

The remaining crude extract usually still contains the cannabinoids in their acidic form. Through controlled heating, known as decarboxylation, these are converted into active forms such as CBD or THC. For the production of highly pure distillates, short-path distillation often follows. This thermal separation process separates the cannabinoids from heavier plant components. The result is a highly concentrated, honey-coloured distillate that serves as a base for Swiss CBD oils and cosmetics and is free from unpleasant-tasting by-products.

• Vacuum distillation protects temperature-sensitive cannabinoids from thermal decomposition.
• Efficient solvent recovery reduces production costs and conserves resources.
• Decarboxylation activates the acidic precursors through targeted thermal treatment.
• Short-path distillation purifies the crude oil into highly concentrated, golden-yellow distillates.

Swiss guidelines and regulatory requirements

In Switzerland, cannabis extraction is subject to strict legal requirements, which depend on the intended use of the final product. For medical cannabis, which has been eligible for medical prescription without a BAG exceptional permit since August 2022, the strict GMP guidelines of Swissmedic apply. Manufacturers must provide seamless proof that the ethanol used is of pharmaceutical quality and that no toxic residues remain in the extract. For CBD products with a total THC content of less than one percent, food or chemical law applies depending on the declaration.

A critical factor in the use of ethanol in Switzerland is the alcohol tax and the associated denaturation. Undenatured ethanol is extremely expensive due to federal monopoly duties, which is why producers usually have to resort to denatured alcohols approved by the Federal Customs Administration. These denaturants must not impair the safety of the final product and must be completely removable during the purification process. Swiss laboratories monitor these limit values using highly sensitive gas chromatography to guarantee the marketability of the extracts.

• Medical cannabis extraction is subject to the strict GMP guidelines of Swissmedic.
• THC limits of less than one percent must be strictly adhered to for Swiss CBD extracts.
• Denaturants in ethanol must be legally approved for the respective product category.
• Residue analyses using gas chromatography ensure purity for the Swiss market.

Efficiency and selectivity compared to other extraction methods

Compared to supercritical CO2 extraction, ethanol extraction is characterized by a significantly higher throughput and easier scalability. While CO2 systems require extremely high pressures and expensive specialized components, extraction with cold ethanol can be realized in comparatively simple low-pressure systems. However, CO2 is superior in the selective extraction of terpenes. Ethanol is a polar solvent and, if cooling is insufficient, tends to also extract undesirable water-soluble compounds such as chlorophyll, sugars, and bitter substances from the plant material.

Compared to extraction with hydrocarbons such as butane or propane, ethanol offers significant safety advantages. Although there is also a risk of explosion with ethanol, which is why production facilities must be certified as ATEX zones, the hazard potential is much more controllable than with highly volatile gases. For the large-scale industrial production of broad-spectrum and full-spectrum extracts, ethanol has therefore established itself worldwide and also in Switzerland as the most economical standard, as it offers an excellent balance of yield, operational safety, and investment costs.

• Higher throughput and easier scalability compared to CO2 extraction.
• Lower investment costs for equipment compared to high-pressure CO2 systems.
• Increased requirement for deep-freezing to prevent chlorophyll co-extraction.
• Safer handling on an industrial scale than highly flammable hydrocarbons.

FAQ