Botanical Extraction: The Value and Ease of Ethanol

cannabis industry
By Matteo Zonta, Chef régional des ventes, Canada, Regional Sales Leader, Canada

One of the safest forms of extraction

Solvent extraction for soluble components of plants is one of the safest forms of extraction and is one of the least expensive options available.

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.

Solvent extraction for soluble components of plants is one of the safest forms of extraction. It provides similar results to other commonly used methods and is one of the least expensive options available, making it popular in the essential oils and botanicals industries. Using common laboratory equipment, it’s easy to create a smooth workflow that is fast, safe and inexpensive.

ethanol extraction

Start with Ethanol

Typically, high-proof alcohols (190 and 200) have been used for extraction applications. Ethanol is emerging as one of the more popular solvents because it is safe for infused edibles and compatible with any type of container. Ethanol also provides consistent results while being easily recoverable. Follow these steps:

Step 1: Soak
Mix plant material with the ethanol. Use enough ethanol so the material is completely submerged. Leave the mixture in an ultralow temperature freezer for 24 hours. The ethanol will separate the soluble components of the extract during this soaking period.

Step 2: Filter
Remove all solid materials with a simple filtration step requiring only a vacuum pump, Büchner funnel, filter paper, and a vacuum flask. After the material has been filtered, a solution of ethanol and extract remains.

Step 3: Separate
Now the extract needs to be separated from the ethanol. To separate the two, use a rotary evaporator. When connected to a vacuum pump, the rotary evaporator uses the vacuum to lower the boiling point of ethanol, resulting in quicker evaporation. The resulting extract or oil will be completely free of ethanol. This process also allows ethanol to be recovered for additional extractions.

Types of equipment

A variety of rotary evaporator sizes are available to fit any application, ranging from laboratory research use to large-scale production plants. If your needs change, ramping up production will not be an issue. If the rotary evaporator is not equipped with a heating bath, one will need to be purchased separately. A recirculating chiller is also needed as this connects to the rotary evaporator to accelerate solvent recovery. After completing these simple steps, the extract is now ready for the next phase of the process.

Need a purer extract?

For a purer extract, winterization is recommended. Winterization is a process where fats, plant lipids, or any kind of waxes are removed from the extract. This can be accomplished by adding ethanol to the extract. Repeat the filtering step and again use the rotary evaporator to boil off the ethanol, leaving a pure extract that can be dried in a laboratory oven or readily infused.

For more information on optimizing your workflow for success, please go to the Cole-Parmer Botanicals resource page.

Read more about solvent extraction using ethanol.

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