Winterization is key step in the extraction and purification of oils derived from cannabis and hemp. How is it used to remove fats and waxes from cannabinoid oils? One of the most critical steps in terms of making a clean cannabis product is CBD winterization. If you’ve ever wondered what that means, click to learn more!
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
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?
What is CBD winterization?
There are many steps to processing hemp into a consumer-level product. One of the most critical, in terms of making a clean product, is winterization. No, this isn’t what your dad does to the lawnmower every fall. Winterization is a process that removes undesirable elements extracted from hemp, for example, fats, waxes, and lipids leaving behind clean, consumable CBD oil. Without CBD winterization, these unwanted materials would cause the final product to be cloudy, darker, and have an unpleasant taste.
What steps come before the winterization of oil?
The winterization process starts with raw extract straight from our CO2 machine (see photo below). This CBD crude oil contains all the essential parts of the hemp plant except for the actual plant material itself. CBD, minor cannabinoids, terpenes, fats, waxes, and lipids are all part of this viscous liquid. Crude oil extracted from a CO2 machine will have an attractive, light color to it, especially compared to alcohol extracted oil, which will have a dark, sludge-like appearance.
What is CBD Winterization?
The CBD crude oil is combined with 200 proof alcohol and stirred vigorously until completely mixed. The alcohol is used to thin the crude oil out, as the desirable parts of crude will go into solution with the alcohol while the undesirable parts will coagulate and freeze allowing them to be filtered out. The mixture is then placed in a deep freezer at below-zero temperatures. Once it has time to freeze it looks cloudy and is ready for filtration. The next step is to place the mixture in vessels that use paper filters to remove the frozen fats, waxes and lipids. The actual CBD oil remains with the alcohol solution and passes through the filter while the frozen undesirable parts are caught by it. The photo below shows what a filter will look like after the solution passes through it. When properly winterized, the filters will catch all of the frozen plant waxes from the oil, leaving them sitting on top. Once the pass is complete, the filters and waxes are discarded. The clean oil flows through the filter into a collection vessel where it is refrozen for more passes. We winterize multiple times just to make sure that our oil is 100 percent clean!
So wait, even though the winterized oil is CO2 extracted, it will still contain alcohol?
Nope! The alcohol is just used to thin the CBD oil in order to properly filter it. Once it’s been filtered and the undesirable elements have been removed, it’s time to remove the alcohol. This is done with a piece of equipment called a rotary evaporator (rotovap). This is CEO Craig Henderson, who started refining hemp from the garage of his home, using a rotovap in the early days of Extract Labs. This bad boy is an efficient way to quickly distill the alcohol out of the solution. The bulb spins in a hot water bath while the system is under vacuum, allowing the alcohol to evaporate out while leaving the winterized oil spinning in the bulb. The alcohol vapors then travel up to the chiller coils where they condense into a liquid and drip down for collection. The alcohol is then recycled into our process. Once the rotovap is done with a work order, the spinning bulb will contain only clean winterized CBD oil. The winterized CBD is then ready to move on to the next phase of the process. From here, the winterized oil will be formulated into tinctures or it will move to our distillation department for further refinement.