Butane (BHO) Extraction and the Importance of Purging


Butane extract

Butane extraction, commonly known as BHO extraction, is a popular method to separate desirable materials out of cannabis and other plant materials. The extraction will produce a product referred to as butane hash oil, or what is also commonly known as a shatter. A shatter contains THC, CBD and Terpenes. While this method of extraction is more efficient than supercritical CO2 extraction, it also is a method that poses some inherent risks. Butane in a gas phase is very flammable, so temperature monitoring for this type of extraction is essential to avoid hazards such as explosion.


BHO extraction is similar to other extraction methods, as it uses a liquid phase solvent, in this case butane, to remove the components such as THC and CBD. However, unlike, alcohol extraction, you should use a closed loop system to prevent any kind of off gassing and also keep the risk of explosion minimal. You will pack stainless steel columns with the plant substance and run liquid butane at extremely low temperatures through the material. This will leave you with an extract of butane and the plant chemicals of interest. Again, this should be done in a closed loop system to prevent risk of explosion.


Cascade Sciences Vaccum Purge Oven

After the extraction is completed and you have a mixture of butane and plant extract, you need to perform a purge. This purging removes any of the excess solvent and ensures the material is not ignited in anyway. Cole-Parmer recommends the use of a BHO purge oven for this step. The oven allows for stable temperature control, making sure that chemicals of use are not burned off. The vacuum ensures temperature does not fluctuate, even at temperatures slightly above ambient. The result is a safe product, free of butane, that also includes the desired THC, CBD and terpenes


While Butane extraction has been controversial in the past, newer, closed loop systems have made the process safe by greatly reducing risk of explosion or harmful off gassing. Butane extraction is gaining popularity as it is more efficient and cost effective than Super Critical CO2 extraction. Ovens designed for the essential purging step have also made a great improvement over the past years and Cole-Parmer can offer a turnkey solution for this critical step, that leaves you with a safe and consistent product.