Winterization, aka dewaxing, is a vital step in creating a high-purity extract oil. Learn why it is necessary in the botanicals industry and 4 easy-to-follow process steps. Winterization is necessary to create a higher purity of cannabinoids. Removing lipids results in a higher quality product. 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?
Winterization: A Vital Step to Botanicals Purification
The importance of obtaining a pure cannabis extract continues to grow. Production companies are making sure their final extracts are free of undesirable components such as waxes, lipids, and fats. Many are achieving this through a process known as winterization. After extraction, winterization is a final step that can be taken to reach a further purification of extract.
Winterization, also known as dewaxing, is a vital step to creating a high-purity extract in the cannabis industry. Winterization is the removal of the unwanted substances including, waxes, lipids, and fats of the plants in the crude extract. It is important to winterize to remove fats because the fats dilute the final concentration of cannabinoids in the final extract which lowers the purity and then affects the overall value. These fats can cause the final extract to be cloudy and less attractive, also resulting in a lower value. Removing the fats and waxes will result in a pure sample, stable viscosity, and a longer shelf life.
Depending on the method of extraction, it could vary the amount of fats that can be removed during the winterization process. A cold ethanol extraction is the best extraction method for minimizing fats in the extract. The CO2 extraction method is usually the method that contains the most amount of fats in the final crude extract. The methods to complete winterization include four steps: dissolve, cool, filter, and boil.
Dissolve the extract in 30 to 60°C of ethanol using a 10 mL:1g (ethanol:extract) ratio. Stirring the solution using a lab spatula or using a magnetic heater/stirrer with a stir bar will do the trick. Now the extract is suspended in ethanol. The waxes, lipids, and fats have now been dissolved in the solution. Solvent at warmer temperatures, completely dissolves the sample. Cooling the solvent, the solubility is decreased, and the waxes are precipitated out. These fats have a lower solubility in cold ethanol compared to warm ethanol, which is why the next step is to freeze the solution.
Using a chiller/freezer, get the solution as cold as possible. Waiting at least 24 hours should enough time for the waxes to precipitate out of the solution. You will notice a layer of fats have formed on top of the ethanol solution.
Once this is complete, a vacuum filtration system is the final step using a vacuum pump, Buchner funnel, and filter paper. The highest surface area filter paper will allow you to filter out as much precipitate as possible. Keeping the funnel and filter papers as cold as the solution will keep the fats from going back into solution after coming into contact with the warmer surfaces. Using separate filters may help with the filtration, as higher micron sized filters will take out most of the fats but using smaller micron filters will filter the smallest particles of fats. Once the filtration apparatus is set up, use a cold pure ethanol to pre-wet the filter paper and apply a vacuum. Then slowly pour the solution onto the filter paper. A build up of fats will block the ability of the filter paper to continue to pull the solution through.
There are now two separate products: the fats, which will look like a brownish butter on top of the filter papers, and a golden translucent oil. This final step is to evaporate off the ethanol from the oil. Ethanol will boil off at 78.5°C atmospheric pressure. Using a hotplate, boil off the ethanol until the solution reaches a thicker viscosity, close to the viscosity of honey. If using a vacuum oven and are pulling -28.5” Hg, this will reduce the boiling point of ethanol to 12.8°C. This process will purify the cannabis solution creating a higher value of the oil with the least amount of impurities.
Solvent at warmer temperatures, completely dissolves the sample. Cooling the solvent, the solubility is decreased, and the waxes are precipitated out.
Why is the Winterization Process Important in Cannabis Oil Extraction?
The winterization process, in simple terms, is the removal of fats, lipids and other unwanted materials from crude oil extract. Winterization is necessary to create a higher purity of cannabinoids. Lipids dilute the cannabinoid fraction, therefore removing them results in a higher quality product.
The transparency of the product is also affected by lipids in distillate. When lipids are not removed, the distillate will not be transparent – this is a sign of a lower-quality and lower-valued product.
Another adverse effect that lipids have in distillate is the way that they burn on coils in vape pens. Lipids will make the vape pen taste burnt which is unsatisfactory to the consumer. Winterization is a key process that differentiates a product from being either low quality or high quality. That directly affects the value of the product that you are creating.
What is the winterization process?
During winterization, a non-polar oil extract is dissolved into ethanol or other polar solvent. The solution is placed in sub-zero temperatures (usually in the range of -20 to -80 degrees Celsius). When using ethanol, the ratio of ethanol to extract is often 10mL ethanol to 1g of oil. However this ratio often ranges between 5ml to 1g and 20ml to 1g.
During this process in the sub-zero temperatures, the lipids float to the top of the solution because of their lower solubility. The ideal time to leave the solution in cold temperatures is at least 24 hours.
There are multiple filters that the solution can go through such as paper filters and metal micro-filters. The lipids are filtered out of the solution through the filtration process and what is left is a high-purity distillate.
Why is winterization important in the cannabis and hemp oil extraction process?
To truly compete in the cannabis and hemp oil industry, winterization is a vital process. As mentioned previously, a winterized solution has more value than a solution that is not winterized.
Not only is value a factor, but customer satisfaction also plays a big role in this process. When an extract has fat and lipids left in it, it burns, vapes and tastes bad. Consumers will not buy this low-quality product again.
The saying “look good, feel good” does not only apply to people, it also applies to distillate. Everyone likes a shiny new product, not a cloudy and murky one. This is especially true for distillate consumers as transparency is an easy indicator of the level of purity in an extract. To ensure that a product can compete in the cannabis industry, winterization must be included in the extraction process.
Want to learn more about the winterization process and how Maratek can help automate and perfect the process with our expertly engineered Turnkey Automatic Winterization System (TAWS)? Contact us today. We would love to answer any questions that you may have.
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?