Why is Post Extraction Processing Necessary?
Hemp oil obtained after subjecting hemp to Carbon dioxide (CO2) Supercritical Fluid Extraction (SCFE) is further processed to obtain products with the desired chemical composition.
Also called refining, post extraction processing of hemp oil includes winterization, de-carboxylation, and distillation . Chromatography serves as a substitute to distillation, particularly when isolating heat-sensitive molecules .
Post extraction hemp processing is geared towards maximizing the cannabidiol (CBD) content in the end product. Another objective is to maintain some amount of terpenes and flavonoids. Many processors also eliminate tetra-hydro-cannabinol (THC) from the extract to avoid legal hassles.
Cannabis contains a number of cannabinoids including CBD and THC. Now, THC is psychoactive, CBD is not . Simply speaking THC intoxicates or gets the user “high,” CBD does not. Rather, CBD delivers multiple health benefits. Terpenes lend a distinctive aroma to the product while flavonoids impart it a specific flavor .
Hemp is cannabis with 0.3% or less dry weight of THC. Cannabis with over 0.3% THC by dry weight is marijuana . While hemp is legal in many parts of the world, marijuana is not . For many, this difference is not clear and introduces unnecessary confusion during the licensing, transport, and use of hemp and its products.
Legal differences are another source of inconsistency. Some states mandate zero THC content in hemp products . Authorities of such states can deny product license. Or hold up the products at the state border. To avoid legal hassles, some manufacturers choose to eliminate THC altogether from their hemp products  via THC remediation.
Post Extraction Processing of Hemp Oil
Starting with winterization, which eliminates waxes, lipids, and fats, post extraction processing moves to decarboxylation and distillation. Decarboxylation makes cannabinoids available in their free form for active interaction with the nervous system – this interplay facilitates their benevolent health impacts.
Distillation selectively separates other ingredients to maximize CBD concentration. Chromatography often acts as an option to distillation.
Winterization is the first procedure and mainly removes waxes from the hemp oil . It also eliminates fats and lipids . These impurities make the oil distasteful, dark, and cloudy . The process involves:
Top producers employ multiple freezing and filtering passes.
Vacuum lowers ethanol’s boiling point and helps retain the more thermally-sensitive elements in cannabis oil. As ethanol evaporates, winterized CBD oil is left behind. Condensers recover the ethanol and re-use it .
Decarboxylation converts cannabidiolic acid (CBDA) into CBD and tetrahydrocannabiolic acid (THCA) into THC. The acids are inactive but CBD and THC are active . CBD is of course the main required ingredient.
Heating the winterized oil and holding it at a specific temperature for a particular duration decarboxylates it i.e. eliminates the carboxyl group from its molecules .
Distillation makes use of the difference in boiling points of the distinct hemp constituents to isolate them. Consider the boiling points of the elements at one atmosphere pressure :
Required processing rate and scale of production determine the distillation process used:
A rotating wiper applies a very thin film of the decarboxylated hemp oil on the heated inner side of a pipe that acts as the evaporative surface . The component boils and its vapors re-convert to liquid in a condenser located outside the evaporator .
Chromatography is an alternative to fractional distillation. One advantage of chromatography is it does not utilize heat for separation. Hemp extract is first dissolved in a fluid (mobile phase) and passed through a media (stationary phase). The difference in speed of passage of the diverse hemp components in the media enables isolation .
Popular chromatography techniques employed in post-extraction processing of hemp include:
Centrifugal Partition Chromatography (CPC) used liquids for stationary and mobile phases. Both phases mix and rotate, with centrifugal force separating and decanting the heavier mobile phase from the lighter stationary phase .
Full Spectrum, Broad Spectrum, & Other Types of Hemp Oils
Refined hemp oils are also called CBD Distillates. Based on the degree to which they are refined, hemp oils can be:
But because they may also contain tiny fractions of THC, they are exposed to the mentioned issues with transport, licensing, and use. Besides, impurities make them unpleasant as edibles .
And yet, people demand them because of the “entourage effect,” the combined, more benevolent effect of multiple cannabinoids .
Manufacturers produce broad spectrum CBD in two ways. First, by refining full spectrum CBD till it is devoid of THC. Second, by adding terpenes and benevolent i.e. non-psychoactive cannabinoids to CBD isolates, the most refined of all hemp oils as described below .
THC remediation removes up to 99.9% THC. Crashing the hemp extract i.e. crystallizing CBD out leaves behind THC-rich mother liquor. Chromatography of this liquor isolates THC. The close boiling points of THC and CBD mean separating them via distillation is a tough task .
Exhaustive post extraction processing transports hemp products to a completely different level, into a class of their own! It is no surprise that the global market for hemp products is on an expansion spree.
Buffalo Extraction Systems (BES) works closely with trusted partners and provides turnkey solutions in Carbon dioxide (CO2) Supercritical Fluid Extraction (SCFE) for over a decade.
Write to us at firstname.lastname@example.org for state-of-the-art CO2 extraction technology.