Winterization
Category: Extraction & Processing · Level: Expert
Winterization is a post-extraction purification process using cold temperatures and ethanol to remove fats, waxes, and lipids from cannabis extracts.
Winterization is the refining step that removes fats, waxes and lipids from a crude cannabis extract. Plant waxes dissolve together with cannabinoids during extraction, especially with warm ethanol, supercritical CO2 or butane. Left in the product they make oil cloudy, harsh to inhale and unsuitable for distillation.
How it works: the crude oil is dissolved in food grade ethanol, often around ten parts ethanol to one part extract, and held between −20 °C and −80 °C for 24 to 48 hours. At that temperature waxes and lipids solidify and settle out of solution. The cold mixture is filtered through filter paper, a Büchner funnel or a filter press, and the ethanol is recovered with a rotary or falling film evaporator. What remains is a clear amber oil ready for decarboxylation and distillation.
Why it matters: winterization is a standard step before making distillate and in most GMP extract production, because waxes foul distillation equipment and lower the purity shown on a certificate of analysis. Cold ethanol extraction, where the plant is washed at very low temperature, pulls fewer waxes and can shorten or skip the step. Solventless products such as rosin and ice water hash are not winterized, and some live resin makers avoid it to keep the most volatile terpenes.
Also known as
Dewaxing, Cold filtering, Ethanol winterization
Used in
- Industrial
- Medical
Related terms
- Distillate: Cannabis distillate is a highly refined extract produced through molecular distillation, typically containing 90%+ cannabinoid purity.
- CO2 Extraction: CO2 extraction is a method of producing cannabis concentrates using supercritical or subcritical carbon dioxide as a solvent, resulting in clean, pharmaceutical-grade extracts.
- Extraction: Cannabis extraction is the process of isolating cannabinoids, terpenes, and other compounds from plant material using solvents or mechanical methods.
- GMP: Good Manufacturing Practice (GMP) is a quality assurance framework mandated by regulatory agencies for the production of pharmaceutical, food, and cannabis products.