Less than a decade ago, cannabis extracts were seen as a fringe market, mainly used in edibles or topical applications towards a small niche of consumers. However, in recent years we have seen a huge shift in the appreciation and uptake of cannabinoid oil extracts, with truly exponential market growth. In 2021, the overall extract market was valued at USD 2.74 billion, with an expectation of around 20% growth in the decade following 2022.  

And with this growth comes the need for greater sophistication in the processing of cannabis extracts. In particular, winterization has become a major focus point for extractors looking to improve the quality and purity of the products they offer.


  • What Is Winterizing?
  • What is the Winterization Process in Cannabis Extraction?
  • Why is the Winterization Process Important in Cannabis Oil Extraction?

Let’s dive in and discuss these questions in more detail.

What Is Winterizing?

When producing cannabis extract that targets the recreational markets, wax, shatter, distillate, or any number of related end products – winterization is a key process that helps improve the overall quality of the product. Put simply, it’s a form of purification that helps eliminate unwanted lipids, fatty acids, wax, and other impurities from the crude oil extract.

If you are a keen cook or have made cannabis-infused butter in the past, then you may be familiar with a simplified version of the winterization process. With the slow-cooked cannabutter recipe, you add water, butter, and your cannabis to a pot and let it boil away for 8 to 12 hours. This is then filtered through cheesecloth to remove the plant material, with the remaining liquid being placed into the freezer to allow the fat and water to separate. The fat rises to the top and solidifies, with the water remaining underneath. This fat is where the cannabinoids are contained.

While this is almost the opposite to extract winterization – where we want to eliminate the fats, lipids, and waxes to increase the purity of the end product – it does show in a simple and easy-to-understand way what winterization is trying to achieve – the removal of unwanted impurities from an oil-based solution through exposure to colder temperatures.

What is the Winterization Process in Cannabis Extraction?

Also sometimes referred to as dewaxing, winterization (in terms of cannabis extraction on a commercial scale) is the second step in a five-step process that ensures the highest purity of the final product.

The Five Steps of Cannabis Extraction

To ensure the highest quality outcome, all cannabis extract producers need to abide by a five-step process that includes:

  • Extraction – The production of the crude cannabis oil
  • Winterization – The crude oil is then winterized to remove the unwanted lipids, fatty acids, and waxes once the oil is mixed with a polar solvent (usually ethanol) and subjected to a sub-zero temperature range for 24 hours.
  • Solvent Recovery – The winterized oil is then sent through a vacuum filtration process, which is the most time-consuming step and can be a true bottleneck in production. This process is vital, as it separates the bulk of the ethanol from the oil, which can then be reused in a closed-loop system.
  • Decarboxylation – The oil is then sent through a decarboxylation (or “decarb”) process, which converts THCA and CBDA into THC and CBD and produces the desired effects when consumed.
  • Distillation – The last step is the distillation process, where a thin-film evaporator is used to further refine and purify the oil, allowing for precise control over the end product’s cannabinoid profile.

Cannabis Extract Winterization

To properly winterize cannabis extracts on a commercial scale, the first step is to mix the crude cannabis oil with a polar solvent such as ethanol, and then place the solution in a freezer for 24 hours. This causes the unwanted lipids, fatty acids, waxes, and impurities that are contained in the plant material to solidify and separate from the desired cannabinoids.

The ratio of the ethanol/crude cannabis oil mixture is most commonly set at 10:1, although this will depend on the extraction method. Carbon dioxide (C02) extraction uses much higher pressures than say, butane, and so more of the contained fats, lipids, and waxes will be present. This allows for the complete dissolution of the trichomes, while also making sure that there is enough solvent available to cause the impurities to solidify and separate from the desired components.

Once the solution has been frozen for the required time frame (usually 24 hours at minimum with a target temperature near -40 degrees Celcius), it is then filtered through a centrifuge, Buchner Funnel or a filter press. It is this filtration process that can cause a marked slowing in production, but this process can be sped up with the aid of modern industry-standard systems.

The end result is an oil that has been winterized; all unwanted compounds have been removed to a much greater degree than what is possible through normal filtration techniques. This winterized oil can then be further purified and refined with the aid of a thin-film evaporator, leading to the production of high-quality distillates.

The Benefits of Winterizing Cannabis Extracts

The winterization process has a plethora of benefits for both the producer and the consumer.

  • Firstly, it produces a final product that is much more potent, purer, and cleaner than traditional methods.
  • The final product contains much fewer impurities, and so the shelf life is much longer, and the product can be stored for extended periods of time without degradation. It also reduces the potential presence of toxic compounds.
  • The “bag appeal” is greatly increased- Winterized extracts are much clearer, cleaner, smoother and free of impurities. The color of the final product is much more appealing, and the viscosity is more stable. This makes them a more desirable product for consumers wanting the highest quality extractions.
  • Finally, the winterization process greatly simplifies and speeds up the distillation process. This allows for faster production times and much greater precision in the final product.