Recommended Crude oil preparation before distillation

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.

150C for an hour? Measuring heating element temp or crude temp? Seems like overkill from most SOP’s I’ve seen, especially for a smaller amount of liquid

That’s the crude temp, so you can remove terpene completely that will not impede vaccum when you run the distillation system.


It’s a complicated question as product composition and vacuum depth are the determining factor for this. 150C for an hour at atmospheric pressure will not remove everything, including most solvents. Vacuum meter shows all.