Extraction Methods

How Concentrates Are Made

Extraction is the process of separating cannabinoids and terpenes from the cannabis plant material. Each method has its own advantages, limitations, and the types of products it produces.

Solvent-Based Extraction

BHO (Butane Hash Oil)

How it works: Liquid butane is passed through cannabis material in a closed-loop system. Butane dissolves cannabinoids and terpenes, then the solvent is purged through heat and vacuum.

Pros:

• Excellent terpene preservation
• Produces a wide range of textures (shatter, wax, budder, etc.)
• High cannabinoid yields
• Industry standard with well-understood processes

Cons:

• Requires extensive purging to remove residual solvents
• Highly flammable — requires professional equipment
• Lab testing is essential to verify safe residual solvent levels

CO2 Extraction

How it works: Supercritical CO2 (CO2 at specific temperature and pressure where it has properties of both liquid and gas) is used as a solvent. Parameters can be tuned to target specific compounds.

Pros:

• No residual solvents — CO2 evaporates completely
• Tunable — can selectively extract different compounds
• Considered very clean and safe
• Often used for vape cartridges and edibles

Cons:

• Expensive equipment ($100K+)
• Can strip terpenes if parameters aren't optimized
• Slower process than BHO

Ethanol Extraction

How it works: Cannabis is soaked in food-grade ethanol, which dissolves cannabinoids. The ethanol is then evaporated, leaving behind the extract.

Pros:

• Scalable for large operations
• Generally Recognized as Safe (GRAS) solvent
• Good for producing distillate and RSO (Rick Simpson Oil)

Cons:

• Extracts chlorophyll and waxes (requires winterization to remove)
• Less terpene preservation than BHO
• Produces darker-colored extracts

Solventless Extraction

Ice Water Extraction (Bubble Hash)

How it works: Cannabis is agitated in ice water, which causes brittle trichome heads to break off. The mixture is filtered through a series of mesh bags (bubble bags) with decreasing micron sizes to collect trichomes by size.

Pros:

• No solvents whatsoever
• Preserves terpenes beautifully
• Can be done at home with basic equipment
• Premium product commands high prices

Cons:

• Lower yields than solvent methods
• Quality highly dependent on starting material
• Time-intensive process
• Requires proper drying to prevent mold

Rosin Press

How it works: Cannabis (flower, hash, or kief) is placed between parchment paper and pressed with heated plates. The combination of heat (170-220°F) and pressure (1,000+ PSI) squeezes out a golden, terpene-rich oil.

Pros:

• Completely solventless
• Can be done at home with a press
• Immediate results — no purging needed
• Excellent terpene and cannabinoid retention

Cons:

• Lower yields (15-25% from flower)
• Quality depends heavily on starting material
• Commercial presses are expensive

Dry Sift (Mechanical Separation)

How it works: Dried cannabis is gently agitated over fine mesh screens. Trichome heads fall through while plant material stays above. Multiple screens of decreasing size can be used for purity.

Pros:

• Simplest method
• No equipment needed beyond screens
• Great for personal use

Cons:

• Lower purity than other methods
• Difficult to scale
• Some plant contamination is inevitable

Residual Solvents Testing

For solvent-based extracts, lab testing is critical. Reputable products include a Certificate of Analysis (COA) showing residual solvent levels. Safe limits are typically measured in parts per million (PPM):

• Butane: < 5,000 PPM (many states require < 500 PPM)
• Propane: < 5,000 PPM
• Ethanol: Generally recognized as safe at higher levels

Key Takeaways

• BHO excels at terpene preservation but requires careful purging
• CO2 extraction leaves no residual solvents but is expensive
• Solventless methods (ice water, rosin) produce premium products without chemicals
• Always check lab results for residual solvents in solvent-based concentrates