CO2 versus butane extractions
CO2 vs. Butane extraction methods for medical marijuana concentrates
Medical marijuana users often misuse the terms hash, concentrate and extract. They are all similar terms used to describe the process of separating the active ingredient in marijuana from the cannabis plant. Concentrates are the resin glands called trichomes, of the cannabis plant. Trichomes are extracted by being filtered through silkscreens to produce Kief. In turn, Kief is pressed to form hash, which is essentially the extracted and concentrated active ingredient, THC and Cannabinoids.
Hash has a plethora of classifying names that identify where it was produced and the method used to create it. Some of the original forms of hash came from East Asia and concentrates were collected by simply rubbing mature cannabis plants in the hands, gathering the trichomes and pressing them together to form a brown or black piece of sticky substance. Sequentially, more methods of extracting trichomes have been unveiled.
Today, there are numerous methods of extracting the active ingredients from cannabis plants. Methods have become more scientific than ever because of the medical marijuana industry. Once the concentrate is extracted, usually in the forms of oil or wax, it can be consumed orally, smoked or vaporized. Medical marijuana users are consuming concentrates more these days because of the low cost compared to the high THC and Cannabinoid content. The two most common methods that concentrates can be extracted are BHO (Butane Extraction) and CO2.
BHO (Butane Extraction)
BHO, Butane Extraction or Butane Hash Oil is a method of extraction that uses the chemical solvent, butane, to pass over the cannabis bud and plant materials. At room temperature, the finished product is soft like ear wax. When heated, it is melted into a clear to yellowish amber oil. At its very purest, it is hard like glass. They have been branded as “BHO,” “Budder,” “Butane Hash Oil,” “Earwax,” “Errl,” “Honey Oil,” and “Shatter.” These are all comparable products, just different appearances and melting points due to the various extraction methods used.
This method is known as Supercritical Fluid Extraction because the solvent, butane, selectively solvates the desirable portions of cannabis oil and dispenses the unwanted diluents behind in the plant materials. Enthusiasts claim that even the most “unpalatable schwag” or commercial grade marijuana yields clean and potent gold oil from the BHO method of extraction. It is important to note that the amount of oil extracted is considerably lower than the volume of cannabis used. For each ounce of cannabis leaf, the BHO method will typically extract between 1 and 3 grams of oil.
This extraction procedure is advantageous for medical use because it renders the leaf into an appropriate consumption form for patients by removing the ash producing materials and tars from the psychoactive principals.
The CO2 extraction method is also known as Supercritical Fluid Extraction and uses carbon dioxide, in the liquid form, as the solvent. Like BHO, CO2 is used to strip out different elements in the cannabis plant to create pure hash oil. Additionally, CO2 is used for cannabis concentrates. This method is a relatively new process, but has become a favorite amongst medical marijuana enthusiasts.
CO2 is the gas we breathe through our lungs and essential food for plants. This is why the oils extracted are, in essence, a “safe liquid solvent.” When a specific amount of pressure is applied to CO2, the gas becomes a liquid. In the case of cannabis extraction, the solvent is pushed through the plant material at such a high pressure separating the plant from the purest essence of the cannabis. The result is transparent amber oil.
Other popular products produced by the CO2 method are decaffeinated coffee, hops for beer and pharmaceutical precursors.
BHO vs. CO2
Butane Extraction and CO2 are chemically inert, but BHO is not a fully oxidized form so there is a chance that it could react negatively with the concentrates during the extraction process.
CO2 is less expensive than BHO, although the proper setup for a CO2 extraction is more expensive than BHO.
BHO is highly flammable and CO2 is not flammable at all.
Medical marijuana extracts made with CO2 are safer for consumption.
Since CO2 is exhaled from the body as waste, high levels of CO2 are dangerous. This fortunately only matters during the extraction process as once the oil is created there is no CO2 residue left behind.
BHO extraction can potentially leave heavy metals behind in the finished product.