¶ BHO/PHO Extraction
Butane hash oil (BHO) and propane hash oil (PHO) are cannabis concentrates produced by passing liquid butane, propane, or a blend of both through cannabis material to dissolve cannabinoids, terpenes, and other compounds. The solvent is then evaporated and purged, leaving behind a concentrated resin.
🚨 BUTANE AND PROPANE EXTRACTION CARRY EXTREME SAFETY RISKS INCLUDING FIRE, EXPLOSION, AND ASPHYXIATION. OPEN BLASTING (USING BUTANE IN OPEN OR IMPROVISED SYSTEMS) HAS CAUSED NUMEROUS FATALITIES, SEVERE BURNS, AND PROPERTY DESTRUCTION. THIS SECTION IS PROVIDED FOR EDUCATIONAL PURPOSES ONLY. HYDROCARBON EXTRACTION SHOULD ONLY BE PERFORMED BY TRAINED PROFESSIONALS USING CERTIFIED CLOSED-LOOP EQUIPMENT IN PROPERLY VENTILATED, CODE-COMPLANT FACILITIES.
¶ What Are BHO and PHO?
BHO (Butane Hash Oil) is produced using n-butane or a butane blend as the primary solvent. Butane is an effective solvent for cannabinoids and terpenes, boiling at approximately 31 degrees F (-0.5 degrees C) at atmospheric pressure, which allows it to be easily removed from the extract.
PHO (Propane Hash Oil) is produced using propane as the primary solvent. Propane boils at a lower temperature (-44 degrees F / -42 degrees C), which allows for faster purging and can produce different consistencies compared to butane. Propane is also more selective, extracting fewer lipids and waxes than butane.
Many commercial operations use blended solvents (butane/propane mixes) to combine the advantages of both: the extraction efficiency of butane and the faster recovery and selectivity of propane.
¶ Open Blasting vs. Closed-Loop Systems
This distinction is the single most important safety factor in hydrocarbon extraction.
¶ Open Blasting -- NEVER ATTEMPT
Open blasting involves filling an open-ended tube or container with cannabis material and butane from a lighter refill canister, then allowing the butane to evaporate into the open air or an unventilated space.
🚨 Danger
Open blasting is extremely dangerous and should never be attempted. Risks include:
- Explosion: Butane is heavier than air and pools in low areas, creating explosive atmospheres
- Fire: Any spark -- from a light switch, static electricity, or pilot light -- can ignite accumulated butane
- Asphyxiation: Butane displaces oxygen in enclosed spaces
- Toxic contaminants: Lighter refill canisters are not food-grade and contain toxic additives
- Legal consequences: Open blasting is illegal in most jurisdictions and carries criminal penalties
Numerous deaths and severe injuries have resulted from open blasting.
¶ Professional Closed-Loop Systems
Closed-loop extraction (CLE) systems are engineered, certified devices that contain the solvent within a sealed circuit throughout the entire extraction process.
| Feature | Open Blasting (Dangerous) | Closed-Loop (Professional) |
|---|---|---|
| Solvent containment | Open to atmosphere | Fully sealed circuit |
| Solvent recovery | Solvent lost to atmosphere | Solvent captured and reused (95%+ recovery) |
| Explosion risk | Extremely high | Minimal when properly operated |
| Solvent quality | Often contaminated lighter fluid | Food-grade or lab-grade hydrocarbons |
| Pressure rating | PVC or other non-rated vessels (catastrophic failure risk) | ASME-rated stainless steel vessels |
| Ventilation | Usually inadequate | Professional ventilation and gas monitoring |
| Legal status | Illegal in most jurisdictions | Permitted with proper licensing |
| Product safety | Unknown; possible contamination | Tested and verified |
¶ Closed-Loop Equipment Overview
A typical closed-loop extraction system consists of:
¶ Main Components
| Component | Function | Notes |
|---|---|---|
| Solvent tank | Stores liquid butane/propane under pressure | Must be rated for the specific solvent and operating pressure |
| Material column (extraction vessel) | Holds the packed cannabis material | Typically 3-8 inch diameter stainless steel tube |
| Collection vessel | Receives the solvent + dissolved extract mixture | Often jacketed for temperature control |
| Recovery tank | Captures solvent after evaporation from extract | Enables solvent reuse; critical for economics |
| Pump | Moves solvent through the system | Vacuum pump and/or recovery pump |
| Pressure gauges | Monitor pressure throughout the system | Essential for safe operation |
| Valves and fittings | Control solvent flow | High-quality, solvent-compatible fittings |
| Vacuum system | Creates vacuum for solvent recovery and extract purging | Critical for removing residual solvents |
¶ System Classifications
| System Type | Description | Scale | Cost |
|---|---|---|---|
| Single-column | One extraction vessel; simple operation | Small to medium | $3,000-$10,000 |
| Dual-column | Two extraction vessels; one extracts while the other is being packed | Medium | $10,000-$25,000 |
| Multi-column/commercial | Multiple large columns; automated; high throughput | Commercial/industrial | $50,000-$250,000+ |
¶ Process Overview
The following is a general educational overview of the closed-loop BHO/PHO process. This is NOT an instruction guide.
¶ Step 1: Prepare and Pack Material
- Cannabis flower or trim is dried to appropriate moisture content (typically 8-12%)
- Material is lightly ground or broken up to increase surface area
- Material is packed into the extraction column, typically between filter screens or papers at both ends
- Packing density affects solvent flow and extraction efficiency -- too tight restricts flow; too loose channels and reduces contact
¶ Step 2: Chill the System
The system is chilled to keep the solvent in liquid form during extraction:
- Solvent tank: Cooled to maintain liquid butane/propane under pressure
- Material column: Often chilled to 10-30 degrees F (-12 to -1 degrees C)
- Collection vessel: Cooled to similar temperatures
¶ Step 3: Pass Solvent Through Material
- Liquid solvent is introduced into the material column from the solvent tank
- The solvent flows through the packed cannabis, dissolving cannabinoids, terpenes, lipids, and waxes
- The solvent + dissolved compounds (now called "miscella" or "crude extract") flows into the collection vessel
- This process may be repeated multiple times ("passes") to maximize extraction efficiency
¶ Step 4: Separate Solvent from Extract
- The collection vessel is warmed slightly or placed under vacuum
- The hydrocarbon solvent boils off (due to its low boiling point) and is captured in the recovery tank
- The remaining crude extract is left in the collection vessel
¶ Step 5: Solvent Recovery
- Solvent in the recovery tank is purified (if the system includes a purification stage)
- The recovered solvent is reused in subsequent runs
- Professional systems achieve 95-99% solvent recovery rates
¶ Step 6: Purging Residual Solvents
Even after initial solvent separation, residual hydrocarbons remain in the extract and must be removed to safe levels.
| Purging Method | Description | Time | Effectiveness |
|---|---|---|---|
| Vacuum oven | Extract placed in vacuum oven at low heat (90-120 degrees F / 32-49 degrees C) under vacuum | 24-72 hours | Most effective; industry standard |
| Heat-only purging | Extract left in a warm, well-ventilated area | Several days to weeks | Less effective; not suitable for regulated markets |
| Vacuum chamber | Extract placed in vacuum chamber without heat | 24-48 hours | Moderate effectiveness |
ℹ️ In regulated markets, residual solvent levels are strictly tested and regulated. Products must meet specific limits (typically below 5,000 parts per million for butane, varying by jurisdiction) before they can be sold.
¶ Types of BHO/PHO Concentrates
The consistency of BHO/PHO is influenced by extraction parameters, purge conditions, and post-processing. Different consistencies are not inherently better or worse -- they represent different molecular arrangements of the same extracted compounds.
| Type | Consistency | How It Forms | Characteristics |
|---|---|---|---|
| Shatter | Hard, glass-like, translucent | Slow, cool purge with minimal agitation | Clean appearance; snaps when cold; can be difficult to work with |
| Wax | Opaque, crumbly, waxy | Faster purge or more agitation during purging | Easy to handle; less visually appealing |
| Budder/Badder | Creamy, whipped, spreadable | Whipping during or after purging; controlled nucleation | Easy to dose; popular consistency |
| Crumble | Dry, crumbly, honeycomb texture | Extended purge at moderate temperatures | Very dry; easy to break apart |
| Live Resin | Varies (sauce, badder, sugar) | Made from fresh frozen material; see Live Resin | Maximum terpene preservation; intense flavor |
| Sauce | Liquid terpene fraction with THCA crystals | Phase separation during extended curing | High terpene content; crystals form over time |
| Sugar | Granular, crystalline THCA in terpene sauce | Controlled crystallization | High THCA content; good terpene profile |
| THCA Diamonds | Large, pure THCA crystals | Extended crystallization in terpene sauce (weeks to months) | 95-99%+ THCA purity; separated from terpenes |
¶ Safety Considerations
¶ Hydrocarbon Hazards
| Hazard | Description | Mitigation |
|---|---|---|
| Flammability | Butane LEL (lower explosive limit): 1.8%; UEL (upper explosive limit): 8.4% in air. Extremely easy to ignite. | Explosion-proof electrical systems; no ignition sources; gas monitoring |
| Explosion | Butane-air mixtures within the explosive range will detonate with any ignition source | Closed-loop containment; professional ventilation; inert gas purging |
| Asphyxiation | Butane and propane displace oxygen, especially in low-lying areas | Oxygen monitoring; proper ventilation; never work alone |
| Frostbite | Liquid hydrocarbons are extremely cold and can cause freeze burns on contact with skin | Cryogenic gloves; eye protection; proper handling procedures |
| Static electricity | Static discharge can ignite hydrocarbon vapors | Grounded equipment; anti-static flooring; bonding during solvent transfer |
| Solvent contamination | Non-food-grade solvents contain toxic additives (mercaptans, etc.) | Only use food-grade or lab-grade hydrocarbons |
¶ Facility Requirements
Professional hydrocarbon extraction facilities require:
- Explosion-proof (Class I, Division 1) electrical systems
- Continuous gas monitoring with automatic shutoff and alarm
- Professional ventilation systems rated for the volume of solvent used
- Fire suppression systems rated for flammable liquid and gas fires
- ASME-rated pressure vessels with proper certification
- Grounded and bonded equipment to prevent static discharge
- Emergency shutoff systems accessible from multiple locations
- Trained personnel with documented safety protocols
¶ Advantages of BHO/PHO
| Advantage | Description |
|---|---|
| High yields | Hydrocarbons efficiently extract cannabinoids and terpenes; yields of 10-25%+ are common |
| Variety of consistencies | Process parameters can produce shatter, wax, budder, sauce, diamonds, and more |
| Terpene preservation | Low-temperature extraction preserves volatile terpenes, especially with fresh frozen material |
| Solvent recovery | Closed-loop systems recover 95%+ of solvent, making the process economical |
| Established technique | Decades of refinement; extensive knowledge base and commercial infrastructure |
| Full-spectrum options | Can produce both full-spectrum extracts and refined fractions |
¶ Disadvantages and Risks
| Disadvantage | Description |
|---|---|
| Explosion risk | Butane and propane are extremely flammable; improper handling can be fatal |
| Residual solvents | Inadequate purging leaves potentially harmful solvents in the final product |
| Regulatory requirements | Licensed facilities, permits, inspections, and compliance add significant cost |
| Equipment cost | Professional closed-loop systems cost thousands to hundreds of thousands of dollars |
| Insurance challenges | Hydrocarbon extraction facilities face high insurance premiums or coverage denial |
| Environmental concerns | Hydrocarbon emissions and waste disposal require careful management |
| Learning curve | Achieving consistent quality requires significant experience and technical knowledge |
¶ Edible Applications
BHO/PHO is widely used in commercial edible production and serves as the starting material for many concentrate-based edible products in legal markets. However, converting BHO/PHO for edible use requires specific safety considerations that are unique to solvent-based extracts.
¶ Suitability for Edibles
BHO/PHO is well suited for edibles when properly processed. The concentrated cannabinoid content makes it an efficient and potent edible ingredient. However, there are critical safety steps that must be followed.
⚠️ Warning
Residual solvent warning: BHO/PHO must be properly purged of residual solvents BEFORE decarboxylation for edible use. If residual butane or propane remains in the extract, the decarboxylation heating process can cause these solvents to concentrate rather than evaporate, potentially resulting in a product with higher residual solvent levels than the starting material. Only use lab-tested BHO/PHO with verified residual solvent levels for edible conversion.
¶ Decarboxylation Requirements
BHO/PHO contains cannabinoids primarily in their acidic forms (THCA, CBDA) and must be fully decarboxylated before use in edibles.
Decarb guidance for BHO/PHO:
- Place properly purged extract in a heat-safe glass container
- Heat at 220-240 degrees F (104-116 degrees C) for 30-60 minutes
- BHO/PHO is a thick oil and may require longer decarb times than solventless extracts
- The extract will bubble vigorously during decarboxylation as CO2 is released -- this is normal
- Ensure adequate ventilation during decarboxylation, as any remaining trace solvents will be released during heating
🚨 Do NOT decarboxylate BHO/PHO that has not been properly purged. Residual solvents heated in an enclosed oven can create fire hazards and will concentrate in the final product. Only use lab-tested material with confirmed low residual solvent levels.
See Decarboxylation for complete temperature and time guidance.
¶ Dosing Guidance
BHO/PHO potency varies depending on extraction quality and consistency:
- Typical BHO/PHO: 60-85% total cannabinoids
- Shatter/wax consistency: Similar potency ranges; consistency does not significantly affect cannabinoid content
Practical dosing example:
- 1 gram of BHO at 70% cannabinoids contains approximately 700mg total cannabinoids
- Assuming ~60% of cannabinoids are THC after full decarboxylation, that equals approximately 420mg THC
- This yields approximately 42 servings at 10mg THC each
- Start with 5-10mg THC equivalent when consuming BHO-based edibles for the first time
¶ Advantages for Edible Use
- High potency: Concentrated cannabinoid content means small amounts produce many servings
- Cost-effective: BHO/PHO is often less expensive per mg of THC than solventless alternatives
- Commercially proven: Widely used in regulated edible manufacturing
- Consistency: Lab-tested BHO/PHO provides known cannabinoid concentrations for accurate dosing
- Neutral flavor: After decarboxylation, BHO/PHO has a relatively mild flavor compared to some other extracts, making it versatile for edible formulation
For detailed edible preparation techniques, infusion methods, and dosing strategies, see Edibles.
¶ Legal Considerations
⚠️ Warning Hydrocarbon cannabis extraction is heavily regulated or entirely illegal in many jurisdictions. Always research and comply with local laws before any extraction activity.
- In legal cannabis markets, hydrocarbon extraction typically requires specific licensing, facility approval, fire marshal inspection, and environmental permits
- Some jurisdictions prohibit hydrocarbon extraction entirely, allowing only CO2, ethanol, or solventless methods
- Home extraction with hydrocarbons is illegal in virtually all jurisdictions
- Open blasting is illegal almost everywhere and carries criminal penalties
See Legal & Safety for general guidance on cannabis law.
¶ Navigation
- Extraction Overview -- All extraction methods
- Ethanol Extraction -- Safer solvent-based alternative
- CO2 Extraction -- Solventless residual alternative
- Live Resin -- BHO from fresh frozen material
- Dabbing -- How BHO/PHO concentrates are consumed
- Cannabinoids -- Compounds extracted
- Terpenes -- Aromatic compounds preserved
- Harm Reduction -- Safety guidelines
This page provides educational information about BHO/PHO extraction. It is NOT an instruction guide. Hydrocarbon extraction carries extreme safety risks and should only be performed by trained professionals using certified closed-loop equipment in code-compliant facilities. Always comply with applicable laws and regulations.