Plant Extraction Methods

Botanical Extraction is placing a solid (plant) in a solvent in order to remove soluble (dissolvable) components, similar to making coffee or tea. Extraction techniques are used to separate the components and remove them from the plant matrix. Various methods can divide plant material into parts, or extracts, that contain different chemicals. Extraction techniques are often used to isolate specific desirable compounds or a producer may seek to create a single extract with many desirable compounds; sometimes called whole plant extracts.

Extraction Methods

Ethanol (EtOH) Extraction

Ethanol (EtOH) Extraction

This extraction is time efficient and has a low solvent-to-feed ratio. Ethanol extraction can be completed at room temperature, but it is recommended to perform such an extraction at ultra-low temperatures for the best yield.
Read the full article on the Ethanol (EtOH) Extraction process.


Liquid Butane (BHO) Extraction

Liquid Butane (BHO) Extraction

Liquid Butane extraction has been used in the food industry to create canola or corn oil. The use of a vacuum purge oven is then utilized to remove the Butane left over from the extraction.
Read full article on Liquid Butane (BHO) Extraction process.


CO2 plant extraxtion

Super Critical Fluid CO2 Extraction

A process that creates phase changes in carbon dioxide utilizing temperature and pressure. Read full article on Super Critical Fluid CO2 Extraction process.

Learning About Extraction Methods


What is Botanical Extraction?

An extraction is the process of removing the desired chemical components from a material to separate it from its initial source. For botanicals, many different parts of the plant can be used, such as the stem, root, flower, or fruit. The result is an oil that contains the compounds of interest without the solid plant material. For example, a cannabis extraction can separate the following elements of the plant:

  • • THC (psychoactive ingredient – Tetrahydrocannabinol)
  • • Terpenes (flavor / medical benefits)
  • • CBD (medical benefits - Cannabidiol)
Botanical extraction can be achieved in roughly 5-6 steps depending on the method. There are currently three different methods that are popular for cannabis and essential oil extraction.


Cannabis Extraction - 3 Main Methodologies

  • • Super Critical Fluid CO2 Extraction (requires recirculating chillers < -60° C)
  • • Ethanol (EtOH) Extraction (Requires chillers, rotary evaporator,and vacuum pump)
  • • Liquid Butane (BHO) or Propane Extraction (usually requires heating circulators, chillers or low temp circulators)

All three methods yield extracts with plant lipids and waxes. These extracts require an additional process called Winterization to remove unwanted components.


Common Terms

  • Grinding - This can be performed on any part of the plant, including the flower, stem, or root. Finely grinding the material creates more surface area for the solvent to interact with, leading to a much more efficient removal of the chemicals of interest. Grinding is typically performed in a laboratory mill, utilizing a blade or grinding balls to reduce the plant into fine particles.

  • Extraction - This process places a solid in a solvent in order to remove soluble components. In most cases, a high proof ethanol is used for plant extraction. For cannabis, this process will remove Terpenes, THC and CBD oil, leaving a mixture of the desired chemicals and solvent. The solvent will later be burned off using a rotary evaporator or a purge oven.

  • Winterization - This process removes fats, plant lipids, or any kind of wax from the extract. Achieved by adding ethanol to the extract using a simple filtration step requiring only a vacuum pump, Büchner funnel, filter paper, and vacuum flask. After the material has been filtered, a solution of solvent and extract remains. Use a rotary evaporator to boil off the ethanol, leaving a pure extract that can be dried in a lab oven or readily infused.

  • Decarboxylation - This process is necessary to activate the psychoactive effects of the cannabinoids present in the cannabis plant or oil. Decarboxylation has a few different meanings, however in this instance, it means replacement of a carboxyl group (-COOH) with a hydrogen atom and releasing carbon dioxide creating THC from THCA. This is achieved by heating the extract or plant material.

  • Distillation/Isolation/Final Processing - This process is not required for infusion or oil use, distillation remains an important step in the research process. By heating the extract at different temperatures, each chemical of the plant extract can be isolated. This is useful to recover CBD oil without THC present and in for any research process where a scientist is looking to study a specific compound of the plant.