Making BHO isn’t a complex process, but it does come with some potential dangers that make it unsuitable for home extraction. Butane is a flammable solvent, thus posing a risk of fire and explosion unless the correct procedures are followed with care. There are several different methods used to extract cannabinoids and terpenes for BHO.
What Is the History of BHO?
Cannabis concentrates have a long history as ancient medicinal substances with the development of hash, or concentrated cannabis resin. The origins of today’s BHO concentrates can be traced back to D. Gold’s 1971 book titled “Cannabis Alchemy: The Art of Modern Hashmaking,” which described a solvent-based process used to make concentrates.
The prevalence of BHO extraction boomed in the late 1990s with the advent of the internet. A 1991 article published on Erowid, an online database for psychoactive compounds, also described the making of the popular hash oil. The “Hash Honey Oil Technique” describes an open-blasting method, which can be dangerous.
Modern methods of BHO extraction are incredibly safe; they use closed-loop extraction methods that capture any residual butane in the air and recycle it, leaving no butane behind.
Open loop Extraction
One of these methods is known as open loop extraction. A tube is loaded with dried cannabis flowers, with a filter attached to one end. Butane is sprayed through the opposing end, and slowly makes its way down the tube, extracting the desired constituents as it goes, until it passes through the filter. Although simple and easy, this method poses the dangers mentioned above, and the basic filtration system may not be sufficient in removing all contaminants from the end product.
The extraction is then heated in what is the most risky part of the procedure. Heating the mixture purges the butane, leaving behind the extracted molecules. This oil is then poured into a tray and left to solidify into a thin, golden, translucent sheet.
This glass-like substance is referred to as “shatter” due to its consistency. However, other BHO makers prefer to whip the mixture up to remove the butane, resulting in a creamier and thicker substance referred to as budder or wax.
This method can also be used to create live resin, using fresh buds that have been snap-frozen after harvest instead of dried flowers. The buds remain frozen during the process using specialized extractors with multiple chambers. One chamber contains the butane, which is chilled and then pushed into the second chamber with the frozen flowers. The butane and extracted constituents are then forced into a third chamber and purified of all lipids and waxes.
What exactly is BHO?
BHO is a cannabis extract that uses the solvent butane to pull the desired constituents from cannabis flowers. The solvent is eventually purged, usually leaving behind a translucent, glass-like substance that can be dabbed and smoked. But this isn’t the only type of BHO. The extract can be crafted into many different consistencies, including budder and wax. BHO provides a clear and clean high, provided it is created properly and with high-quality plant material.
Preparing the starting material
Theoretically, any part of the plant can be used for extraction as long as it has trichomes. Technicians who know how to make hash oil most commonly use trim or whole buds. BHO derived from whole flower result in extracts with richer flavor and higher potency, pulling cannabinoids and terpenes from the areas where they are most abundant.
The most important thing to keep in mind when sourcing the starting material is the percentage of water in the buds. Most of the flowers available at a dispensary average 6 percent water by dry weight. Plants for solvent extraction typically need to be less than 1 percent.
There are three main types of starting material: live resin, nug run, and trim run. Live resin indicates the flowers are newly harvested and flash frozen to trap any terpenes that would be lost during the drying stage. Nug run is flower that has been thoroughly dried and cured after harvest. Trim run consists of the leftover parts of the cannabis plant after the initial trimming. Trim run is considered the lowest quality starting material, with nug run and live resin being of higher quality.
How Long Do You Purge BHO?
Extractors pack the starting cannabis into the material column, a tank inside the closed-loop system that is dedicated to holding the nugs or trim throughout the process. The tank must be purged of any oxygen prior to passing the butante through to ensure that there is no explosion and unnecessary pressure.
The butane is chilled, then passed through the starting material, releasing the trichomes from the plant matter. To remove the butane from the solution, heat is applied to the combined mixture of cannabis and butane, causing the butane to turn into a vapor and rise into the solvent column.
As the vapor reaches the solvent column, it is cooled and condensed back into a liquid.
Some concentrates undergo additional processes, such as charcoal washing or additional wash cycles with other solvents, to render a purer product.
Why Is Hash Oil So Potent?
The reason butane hash oil is so potent is because it’s a concentrated form of marijuana that contains a high percentage of cannabinoids. These are the active ingredients in marijuana that are responsible for its effects.
Cannabinoids interacts with the endocannabinoid system located throughout the brain and human body. In that system lie many cannabinoid receptors. There are CB1 receptors in the brain and nervous system, as well as CB2 receptors in the immune system. The body produces chemicals that plug into these receptors to produce various effects such as reduction of pain and increased immunity.
Cannabinoids such as THC and CBD mimic the chemicals that occur naturally in the body. They can also plug into receptors in the endocannabinoid system – and this is how cannabis causes effects such as euphoria and increased appetite. Unlike smoking marijuana flower, consuming butane hash oil provides a way to ingest large amounts of cannabinoids in a very short period of time.