Purification

Purification is the series of manufacturing steps that remove unwanted plant material, fats, chlorophyll, solvents and specific cannabinoids from a crude extract to reach a desired composition.

A crude hemp extract from carbon dioxide or ethanol extraction contains cannabinoids alongside waxes, lipids, pigments and terpenes. Winterization chills the extract in ethanol so that waxes and fats solidify and can be filtered out. Distillation separates cannabinoids from remaining impurities by their boiling points under vacuum, producing a distillate. Chromatography can then isolate a single cannabinoid or remove THC to make a broad spectrum product, and crystallization yields CBD isolate at very high purity.

Each additional step narrows the composition, which is the trade-off between full spectrum, broad spectrum and isolate products, and each step is a point where residual solvents can be introduced and must later be tested for. Purification is also where THC remediation takes place for products that must stay within the legal limit. On a certificate of analysis, the results of purification show up as the cannabinoid profile and the residual solvent panel rather than as a separate line.