Well processed crude oil prior to distillation is critical to prevent off-gassing during distillation that will impede vacuum and significantly reduce throughput, product quality and potency. The following steps should be taken prior to distillation.
- Extraction : Extraction methods using CO2 (Carbon Dioxide), Light Hydrocarbon (Butane, Propane, etc.) or Cold Ethanol (processed between -40˚C to -60˚C or lower) are all suitable for the following processes. The “raw extract” that results directly from an extraction will vary widely depending on the solvent and method.
- Winterization and Filtration : This is to remove the plant lipids, fats and waxes, the process normally happens in a jacketed reactor followed by a vacuum filter, or a filter reactor system.
- Ethanol recovery : Recover the ethanol by evaporators, such as Rotary Evaporator, falling film evaporator or thin film evaporator.
- Decarboxylation: Decarboxylation modifies the molecular structure of the constituents of the oil by removing the Carboxylic acid attached to Cannabinoid acids. It requires the crude oil to be heated to a moderate high temperature for a few hours to release the gas molecules in the crude oil. There are different methods to do decarboxylation such as hot plate method, reactor method. For example, hot plate method: 1) heat and stir the crude oil in the beaker on a magnetic hot plate; 2) heat oil to around 80 oC, adjust stirring speed according to the viscosity of the oil, wait until no bubble forms. If terpene collection is not a concern, continue to heat the oil at 150 oC for 1 hr.