How To Make RSO Oil: A Complete Masterclass On Solvent Extraction

Rick Simpson Oil (RSO) is a whole-plant, full-spectrum cannabis extract produced through high-proof alcohol extraction and slow solvent evaporation. Achieving pharmaceutical-grade purity requires rigorous temperature control, food-safe food-grade ethanol, and strict adherence to safety protocols to eliminate residual toxins safely.

Pre-Operation & Equipment Checklist

Producing high-purity RSO at home or in a controlled workshop environment demands meticulous preparation, commercial-grade safety equipment, and precise measurement tools. Because this process involves flammable solvents and open heating elements, establishing a spark-free, well-ventilated workspace is non-negotiable for operator safety and extract integrity.

• Essential Gear and Materials:

  
  
  
  • 1 ounce (28 grams) of high-quality dried cannabis material (flower or trim)
  • 500ml to 1000ml of high-proof food-grade ethanol (minimum 190 proof / 95% concentration, such as Everclear)
  • 1 large Pyrex glass mixing bowl or glass pitcher
  • 1 electric rice cooker or digital hot plate with precise temperature control (no open gas flames)
  • 2 fine-mesh metal strainers and unbleached cheesecloth or coffee filters
  • 1 digital infrared thermometer or thermocouple probe
  • 1 silicone spatula for scraping viscous resin
  • 1 glass syringe or amber glass vials for final storage
  • 1 organic vapor respirator and nitrile gloves

• Prerequisite Standards and Benchmarks:

  
  
  
  • Workspace must feature active exhaust ventilation or cross-breeze outdoor flow.
  • Estimated operational duration: 3 to 4 hours from initial decarboxylation to final collection.
  • Target evaporation temperature threshold: 75 degrees Celsius to 90 degrees Celsius (167 degrees Fahrenheit to 194 degrees Fahrenheit) to prevent terpene degradation and cannabinoid oxidation.

Step-by-Step Extraction and Reduction Workflow

Step 1: Material Decarboxylation

Raw cannabis contains cannabinoids predominantly in their acidic forms (such as THCA and CBDA), which lack the desired bioavailability for topical or oral ingestion. To convert these acids into their active forms, break down the plant matter coarsely by hand—avoiding fine powdering, which allows excess chlorophyll and plant waxes to pass through the filter—and spread it evenly across a parchment-lined baking sheet. Place the tray into a preheated oven calibrated to 110 degrees Celsius (230 degrees Fahrenheit) for 40 to 45 minutes, ensuring the internal oven temperature remains stable to maximize activation without scorching volatile aromatic compounds.

Pro-Tip: Monitor the oven with an independent digital oven thermometer, as residential appliance thermostats frequently fluctuate by 10 to 15 degrees, which can degrade delicate terpenes or leave cannabinoids under-decarboxylated.

Step 2: Solvent Extraction and Agitation

Transfer the thoroughly decarboxylated plant material into a deep glass container and submerge it completely with your sub-freezing, high-proof ethanol solvent. Pre-chilling both the solvent and the plant matter in a freezer for 24 hours prior to extraction minimizes the extraction of unwanted chlorophyll, lipids, and water-soluble plant pigments. Using a wooden spoon or silicone spatula, gently agitate and crush the submerged plant material for precisely 3 minutes, ensuring the solvent strips the trichome heads efficiently without extracting harsh vegetal contaminants.

Step 3: Primary and Secondary Filtration

Position a fine-mesh metal strainer lined with unbleached cheesecloth over your clean Pyrex collection vessel, and pour the botanical slurry through to catch large particulate matter. Follow this initial coarse pass by filtering the liquid a second time through a fine paper coffee filter to remove micro-particulates and suspended plant dust. Press the remaining wet plant matter gently within the filter to extract residual solvent, then discard the spent biomass responsibly.

Step 4: Controlled Solvent Evaporation

Pour the filtered golden-green tincture into your electric rice cooker or glass vessel resting on a digital hot plate, and activate the heating element while maintaining a consistent temperature between 75 degrees Celsius and 90 degrees Celsius. Never allow the liquid to exceed 120 degrees Celsius, as excessive heat will degrade active compounds and darken the oil prematurely. Maintain continuous mechanical airflow via an explosion-proof or brushless fan across the surface of the liquid to accelerate evaporation and prevent dangerous vapor pooling.

Warning: Never use gas burners, stovetops with pilot lights, or standard kitchen appliances with exposed heating coils, as ethanol vapors are highly flammable and can easily ignite in enclosed unventilated areas.

Step 5: Final Purge and Collection

As the volume of liquid reduces significantly, add a few drops of distilled water (approximately 1 milliliter of water per ounce of starting material) near the end of the evaporation cycle to help purge trapped residual alcohol and lower surface tension. When the bubbling subsides entirely and the mixture takes on a thick, dark, mirror-like consistency, turn off the heat source. Immediately draw the warm, fluid extract into a pre-warmed oral syringe before it cools and solidifies, storing the final RSO in UV-resistant amber glass containers in a cool, dark environment.

Parameter Comparison: Extraction Methods & Solvents

Common Operational Failures and Field Fixes

• Problem: The final extract remains stubbornly watery or tastes sharply of alcohol long after the evaporation phase has concluded.

  
  
  
  • Root Cause: Insufficient thermal energy applied during the final purge phase, or trapped water molecules preventing complete solvent release.
  • Actionable Fix: Reheat the extract on a warm hot plate at 80 degrees Celsius for an additional 20 to 30 minutes while maintaining continuous airflow, and add 5 drops of warm distilled water to break the molecular bond holding the remaining alcohol.

• Problem: The finished RSO is excessively bitter, cloudy, dark green, and leaves a heavy sludge residue.

  
  
  
  • Root Cause: Over-agitation during the solvent wash or using room-temperature solvent, which strips excessive chlorophyll, waxes, and plant lipids.
  • Actionable Fix: Ensure both solvent and biomass are frozen to -20 degrees Celsius prior to washing, and restrict agitation time to under 3 minutes on subsequent batches.

• Problem: The extraction yields significantly less oil than expected given the weight of the starting material.

  
  
  
  • Root Cause: Incomplete washing of the plant matter or excessive loss of tincture retained in the spent biomass during filtration.
  • Actionable Fix: Perform a secondary wash of the strained plant material using a fresh, smaller volume of chilled ethanol, then combine and filter both washes together before evaporation.

Frequently Asked Questions

What is the ideal cannabis-to-solvent ratio for making RSO?

The standard benchmark requires approximately 500ml of high-proof ethanol per 1 ounce (28 grams) of dried plant material for the first wash, with an optional 250ml wash for secondary extraction. Using sufficient solvent ensures complete submersion and efficient stripping of trichome heads without creating an unnecessarily large volume of liquid that takes too long to evaporate.

Can I use isopropyl alcohol instead of grain alcohol?

No. While isopropyl alcohol is a powerful solvent, it contains chemical denaturants and toxic additives that are unsafe for human consumption, even in trace residual amounts. Always use food-grade, high-proof consumable ethanol such as 190-proof Everclear for extracts intended for therapeutic or oral use.

How long does finished Rick Simpson Oil last in storage?

When stored in an airtight, UV-resistant amber glass container kept in a cool, dark, and dry environment, RSO maintains its chemical potency for 1 to 2 years. Cannabinoids degrade slowly when exposed to light, heat, and oxygen, so minimizing environmental exposure preserves efficacy.

Is decarboxylation mandatory before extracting with alcohol?

While alcohol extraction strips cannabinoids regardless of whether the plant is raw, decarboxylation must occur either before the wash or immediately after solvent evaporation. Performing decarboxylation beforehand ensures the end product contains activated compounds ready for immediate therapeutic utilization without requiring secondary thermal post-processing.

Mastering pharmaceutical-grade home extraction techniques transforms raw botanical material into a potent, reliable full-spectrum extract with predictable therapeutic outcomes. Implement rigorous safety protocols, maintain strict temperature vigilance, and test your procedures for complete solvent removal to ensure absolute product purity.