Winterization of Oils to Remove Fats and Waxes

Cannabis and hemp are botanically complex, containing a rich assortment of carbohydrates, insoluble fibres, proteins, chemicals, and vitamins. Among the most valuable constituents of the Cannabis sativa and indica plant species are—of course—cannabinoids like cannabidiol (CBD) and tetrahydrocannabinol (THC). Extracting these compounds from the raw plant material and purifying it into a high-purity end-product requires a multi-step workflow, from harvesting through to winterization.

Why Winterize Oils?

Fractional distillation alone will often fail to remove unwanted lipids like fats and waxes from oil extracts. This can have a direct effect on the end-product, diluting potency, reducing clarity, and generally leading to a distillate of overall reduced quality.

Winterization is key step in the extraction and purification of oils derived from cannabis and hemp. It involves the fractional crystallization of the extract using butane or high proof ethanol at cryogenic temperatures, or liquid carbon dioxide (CO₂). Cold ethanol winterization is usually preferred as it is relatively inexpensive and quick, but it tends to produce darker extracts. We compared the impact of different extraction methods in a recent article: What is the Winterization Process?

In cold ethanol winterization, the raw, unfiltered extract is mixed in the alcohol solution until fully combined then cooled to temperatures approaching -80°C. Critical winterization parameters include cooling rate, temperature of crystallization, and molecular mobility within the oil mass, as these variables directly influence the precipitation of solid fats and waxes.

Once winterization of oils and fats is complete, the heterogeneous crude mixture can then be filtered using traditional filteration equipment. It may also be decarboxylated to convert cannabidiolic acid (CBDA) into CBD, producing higher concentration extracts. The filtrate is concentrated down to separate the ethanol from the cannabinoid oil; a term often referred to as post-winterization

Post-Winterization Equipment

The type of equipment used in post-winterization depend on the method used. Both sub- and supercritical CO₂ extraction typically use falling film evaporators, but such a bulky and large-scale apparatus is unsuitable for modern cannabis facilities.

Cannabis today represents a booming global industry contributing billions of dollars to economies around the world. Producers looking to drive the bottom line and increase profit margins without compromising the quality of their product offering must be able to distil and purify large volumes of oil quickly and effectively. The falling film evaporator is unfortunately unsuitable for such an initiative, particularly for small-scale laboratories looking to produce high-quality cannabinoid oils on a budget.

At Ecodyst, we have pioneered a new extraction and platform based on a proprietary cooling technology that maximises yields, quality, and time. If you would like to learn more about how our evaporators are used in post-winterization processes, why not contact a member of the team today?