Cannabis extracts: 5 methods of extraction of cannabinoids and terpenes

Extraction is a process that has been used for centuries to create natural by-products from many types of plants. In short, the goal is to collect desirable compounds while leaving behind unwanted compounds and unusable plant material. In the world of cannabis extracts, there are many types of products that we have known for centuries – teas and tinctures, for example – while other types of products are more recent innovations.

Cannabis extracts – basics

The extraction of cannabis is comparable to the processes used to decaffeinate coffee, produce vitamins and minerals, and create essential oils. The main compounds that producers seek to cannabis extracts are cannabinoids and terpenes – these compounds give the final product its aroma, flavour and effect. While extraction is primarily aimed at collecting desirable compounds, there are also undesirable compounds, such as fats and chlorophyll, that extractors may wish to avoid. Extraction is a double-edged sword, as the longer and more aggressive the process, the more desirable and undesirable compounds the extract will contain. You can do a shorter extraction, where you remove fewer desirable compounds, but give a cleaner primary extract, or you can do a really aggressive extraction, where you get a better yield, but you have to do more clean-up to get rid of the unwanted material.

Cannabis extracts – methods

Common extraction methods for cannabis include alcohol, butane, CO2, water and ethanol. All of these solvents are used to separate the cannabinoids and terpenes from the cannabis plant. Each extraction method has its own advantages, but the goal of each is to provide a very potent and clean end product.

The most frequent methods of extracting cannabis are :

1. BHO extractions

Butane honey oil extraction (BHO) has been extensively studied and is widely used in the food and perfume industries. The extraction method requires that cannabis be placed in a container before butane is sprayed onto the cannabis to start the extraction process.The cannabinoids and butane are collected in another container. The mixture is then allowed to evaporate. Alternatively, a vacuum oven can be used to remove all the butane from the mixture. The extraction of BHO is dangerous due to the high flammability of the substance, but closed systems have made the extraction of BHO much safer. THC levels, when the BHO extraction method is used, remain around 80%.

3. Ethanol cannabis extracts

Cannabis producers are beginning to use ethanol extraction methods more often. The extraction is safe, efficient and effective. Ethanol is often used as a food preservative and is considered generally safe. The cannabis plant is soaked in ethanol to extract the THC. Once extracted, the product undergoes a refining process that improves the purity of the product. The ethanol removes unwanted compounds from the substance, resulting in one of the purest and most flavourful concentrates available. The key to ethanol extraction is to ensure that the product is properly refined.

2. Oil extraction by supercritical CO2

CO2 extraction is a non-toxic and environmentally friendly method of separating cannabinoids from the cannabis plant. The extraction method leaves no trace of toxins behind and is also used in the food industry. The supercritical CO2 is heated and passed through the cannabis flowers. The liquid is passed through a separator which separates the CO2 gas from the trichomes and terpenes. As an environmentally friendly method, the gas is pushed through a condenser which allows the gas to liquefy again and be recycled so that it can be used in the extraction process in the future. CO2 extraction requires precise equipment, but it is an excellent method for making waxes and oils.

4. Cold water cannabis extracts

Water extraction is a solvent-free method that involves immersing the cannabis plant in ice water. The plant is stirred in the cold water, which causes the trichomes to separate from the plant. Once the trichomes have fallen off the plant, it is passed through a series of sieves. The end result is a hashish that contains 50% to 70% THC,

5. Isopropyl extraction

Isopropyl alcohol is required for this extraction method. Dried cannabis flowers are soake and then gently shaken. The isopropyl removes the trichomes from the plant. The mixture is filtered into a dish and the solvent is removed using a vacuum oven that maintains a temperature below 181 degrees. When the solvent evaporates, the remaining substance is an oil rich in THC.

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