Butane honey oil (BHO) is a highly concentrated cannabis extract made by using liquid butane as a solvent to strip cannabinoids and terpenes from plant material. It can contain up to 90% THC, compared to roughly 15–25% in typical cannabis flower. BHO goes by many street and dispensary names, including “dab,” “shatter,” “wax,” “amber,” and “honey.”
How Butane Extraction Works
The chemistry behind BHO is straightforward: butane is a nonpolar solvent, and cannabinoids like THC are also nonpolar molecules dominated by carbon and hydrogen. Because similar chemical structures dissolve each other easily, liquid butane pulls cannabinoids and terpenes out of cannabis plant material while leaving behind most water-soluble compounds like chlorophyll.
In practice, butane starts as a gas at room temperature but is either cooled or pressurized into a liquid before being pushed through a tube or vessel packed with cannabis. As it flows through, it dissolves the desired compounds. The resulting liquid is then collected, and the butane is removed through evaporation and purging, leaving behind a sticky, potent concentrate.
Open Blasting vs. Closed-Loop Systems
There are two fundamentally different ways to perform butane extraction, and the gap between them in terms of safety and product quality is enormous.
Open blasting uses an unsealed tube with an open end. Butane gas can escape freely into the surrounding environment during extraction, creating a serious explosion and fire risk. Because butane is heavier than air, it pools at ground level and can ignite from any spark, pilot light, or static discharge. Amateur home operations using this method have caused fires, explosions, severe burns, and deaths. A Colorado study published in the Journal of Medical Toxicology documented a wave of burn injuries directly tied to home BHO production as cannabis laws loosened.
Closed-loop systems, used in licensed commercial operations, seal the entire process off from the outside environment. Butane never escapes into the air, which eliminates the explosion risk. These systems also operate under greater pressure and allow for more precise temperature control, producing a cleaner and higher-quality extract in less time. In a closed-loop system, the solvent is recovered and recycled rather than vented, so the final product never contacts residual butane the way it can in open blasting.
Why BHO Comes in Different Forms
BHO isn’t a single product. The same extraction process can yield dramatically different textures depending on how the concentrate is handled after the butane is removed.
- Shatter is a translucent, glass-like sheet. It’s made by spreading the extract thin and purging it in a vacuum oven for roughly 48 hours without any agitation. The lack of whipping keeps the molecular structure uniform, giving it that brittle, clear appearance.
- Budder has a smooth, creamy consistency similar to cake frosting. The difference is a gentle whipping step during the purge phase, which introduces air and causes the cannabinoids to crystallize while the butane evaporates. This creates a softer, more opaque product.
- Crumble is dry and breaks apart easily. It’s purged at lower temperatures for a longer period than other forms, producing a drier, more porous texture. The extract is spread on parchment paper and left in a vacuum oven until most of the moisture and solvent are gone.
All three forms start from the same crude extract. The variation comes entirely from temperature, agitation, and purge time.
The Purging Step
Removing residual butane from the final product is one of the most critical parts of BHO production. Vacuum ovens are the standard tool: they lower the air pressure inside the chamber, which allows butane to evaporate at much lower temperatures than it normally would. This protects heat-sensitive cannabinoids and terpenes from breaking down.
Typical purging temperatures range from 85°F to 105°F, and the process can take anywhere from a few hours to several days depending on the thickness of the extract and the equipment. In regulated markets, the finished product is tested for residual solvents. Ohio, for example, sets the limit for residual butane at 5,000 parts per million. Products that exceed these thresholds fail testing and cannot be sold.
How BHO Compares to CO2 Extracts
The main alternative to butane extraction in commercial cannabis production is supercritical CO2 extraction, which uses pressurized carbon dioxide instead of a hydrocarbon solvent. Each method has trade-offs.
BHO generally preserves more of the plant’s original terpene profile because butane has an extremely low boiling point (around minus 0.5°C). This means the extraction happens at temperatures low enough to keep volatile flavor compounds intact. The result is concentrates with richer, more complex flavor. The downside is that butane can also pull chlorophyll from the plant, which sometimes affects taste.
CO2 extraction is better at filtering out chlorophyll, but the higher pressures involved tend to degrade terpenes. This can produce a cleaner-looking extract that’s less flavorful. CO2 also leaves no toxic solvent residue, which is one reason it’s considered safer from a consumer health perspective, though properly purged BHO should also fall well within residual solvent limits.
Health Risks of Dabbing BHO
BHO is most commonly consumed through “dabbing,” which involves heating a small amount of concentrate on a superheated surface (usually a nail or banger made of quartz, titanium, or ceramic) and inhaling the vapor. The extreme heat involved, often exceeding 500°F, creates health concerns beyond those associated with smoking cannabis flower.
Research published through the National Center for Biotechnology Information found that dabbing exposes users to toxic byproducts formed when cannabinoids and terpenes break down at high temperatures. These include benzene (a known carcinogen), toluene, methacrolein, and methyl vinyl ketone. Of these, methacrolein accounted for 91% of the calculated health hazard from dabbing in the study. Methacrolein is a potent irritant to the lungs and airways.
The mechanism works like this: terpenes in the concentrate decompose into isoprene when heated, and isoprene then oxidizes into methacrolein and methyl vinyl ketone. Lower dabbing temperatures reduce the formation of these compounds, which is why many experienced users advocate for “low-temp dabs” as a harm-reduction strategy.
The sheer potency of BHO also raises concerns about tolerance. Regularly consuming a product with up to 90% THC can rapidly shift your baseline tolerance upward, making lower-potency cannabis feel ineffective. For people prone to cannabis-related anxiety or panic, the intensity of a dab can be overwhelming compared to smoking flower.