Short answer
Making RSO at home with a flammable solvent carries two main risks: fire and solvent poisoning. Open-air evaporation of ethanol, isopropyl alcohol, or naphtha in a kitchen has caused house fires and burns. The safer route is to buy lab-tested RSO from a licensed store. If you extract at home, use a closed-loop system and a vacuum purge chamber, work outdoors, and keep ignition sources at least 25 feet (7.6 m) away.
What RSO is
RSO stands for Rick Simpson Oil. It is a full-spectrum cannabis extract. The method: soak decarboxylated cannabis flower in a solvent, strain out the plant matter, then evaporate the solvent. What stays behind is a thick, dark tar. THC content in finished RSO runs from about 50% to 80%. Cannabinoid levels change with strain, solvent, purge time, and heat.
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Why the home method is dangerous
Solvent vapor is the hazard, not the liquid.
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- Ethanol flash point: about 13 °C (55 °F). Isopropyl alcohol: about 12 °C (53 °F). Naphtha ignites at lower temperatures.
- Vapor is heavier than air. It pools at floor level and moves to water heaters, pilot lights, and refrigerators.
- A spark from a light switch or a phone can ignite a vapor cloud.
- Incomplete purge leaves solvent in the oil. Solvent residue can cause headache, dizziness, and nausea. High exposure can damage the liver and nerves.
- Cannabis flower can carry mold, pesticides, and heavy metals. Solvent and heat do not remove them. They concentrate in the oil.
Rules if you still extract
- Work outdoors or in a dedicated room with cross-ventilation and no ignition sources within 25 feet.
- No stove, no open flame, no hot plate with an exposed element.
- Use a closed-loop extractor with a pressure relief valve. Or use a vacuum purge chamber rated for solvent work.
- Store solvent in an approved safety can. Ground metal containers and bond them during transfer.
- Wear nitrile gloves, sealed goggles, and a respirator with organic vapor cartridges.
- Keep a Class B fire extinguisher within reach. Class B covers flammable liquids.
- Never heat a sealed jar. Never use a microwave.
Steps
Timeline: about 4 to 8 hours of work, plus purge time.
How to Start with a Small Dosage of RSO
- Decarboxylate. Spread ground flower on a tray. Heat at 105 °C (220 °F) for 40 minutes. THC acid converts to THC.
- Freeze flower and solvent for 24 hours. Cold solvent pulls less chlorophyll.
- Cover flower with solvent in a sealed vessel. Soak 3 to 5 minutes. Agitate for 1 minute.
- Strain through a coffee filter into a second vessel.
- Repeat the wash once for higher yield.
- Evaporate. Use a vacuum purge at 38 to 46 °C (100 to 115 °F). Fit a cold trap between the chamber and the pump. This step takes 4 to 12 hours.
- Purge until no solvent odor remains. Odor is a weak test. A lab panel is the real test.
Testing
Send 1 gram to a cannabis lab. Ask for potency, residual solvents, pesticides, and microbials. State programs set residual solvent limits, often in the parts per million range. Without a panel, you do not know what is in the oil.
Dosing
Potency varies by batch. Weigh portions on a 0.001 g scale. A 10 mg THC dose equals about 14 mg of a 70% oil. RSO is thick at room temperature. Warm the syringe in your hand to move it. Start with 1 mg to 2 mg of THC and wait 2 hours before the next dose.
Legal notes
RSO is a cannabis concentrate. In the US, rules follow state law. Some states limit concentrate sales or require a medical card. Federal law lists cannabis as a Schedule I substance. Check your state rules before you buy solvent or make oil.