Food-grade ethanol in a short, cold wash is the top pick for making RSO oil at home. The ranking rests on four criteria: solvent danger, how much wax and chlorophyll the wash pulls from the plant, how hard the oil is to purge, and whether home extraction fits your state law. Each method below is judged against those points rather than against brand names or price.
Method 1: Food-grade ethanol quick wash (top pick)
Ethanol sold as 190 proof drinking alcohol or as food-grade 200 proof pulls cannabinoids in seconds. Keep both the flower and the alcohol in a freezer overnight, then combine them for one to three minutes. A short contact time limits chlorophyll, which keeps the finished oil amber instead of dark green.
- Pros: Available where liquor is sold, and far less toxic than naphtha.
- Pros: Fast wash time and a predictable purge.
- Pros: The same solvent appears in commercial tincture production, so equipment and guides are easy to find.
- Cons: Still flammable, so it needs outdoor air or a fume hood.
- Cons: 190 proof ethanol carries water, which can slow evaporation and leave a cloudy oil.
Use this route if you want a repeatable batch and you have a safe outdoor space with no pilot lights, grills, or running motors nearby.
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Method 2: Isopropyl alcohol or naphtha (the traditional Rick Simpson route)
The original RSO instructions call for 99% isopropyl alcohol or naphtha. Both dissolve THC and other cannabinoids, and both evaporate at room temperature. They are also harsh solvents, and naphtha is hard to purge from a sticky oil.
- Pros: Cheap and easy to source in most hardware stores.
- Pros: Evaporates fast, so the wash step takes minutes.
- Cons: Isopropyl is not meant for human consumption, and residue is a real risk in a home purge.
- Cons: Naphtha is a petroleum distillate with a strong odor and a low flash point.
- Cons: Long washes with either solvent pull heavy chlorophyll and make the oil bitter.
Use this route only if ethanol is impossible to obtain and you accept that lab testing for solvent residue is the only way to confirm a clean purge.
Method 3: Solvent-free routes (rosin and infused oil)
Rosin presses and coconut oil infusions skip solvent. They do not make true RSO, and the potency per gram is lower, but they carry no risk of solvent residue.
- Pros: No flammable liquid, so a kitchen setup is workable.
- Pros: No purge step and no solvent taste.
- Cons: Lower yield from the same flower.
- Cons: Heat and pressure degrade some terpenes and shift more THC to CBN over time.
Use this route if you cannot ventilate a space or you want an edible base rather than a concentrated oil for a syringe.
Step-by-step for the ethanol method
- Decarboxylate the flower. Break buds into small pieces and bake at 240 F (115 C) for 30 to 45 minutes. This step converts THCA into THC.
- Freeze the decarbed flower and the ethanol for at least four hours, or overnight.
- Combine them in a sealed jar. Shake for 60 to 180 seconds, no longer.
- Strain through a coffee filter or a fine mesh bag into a second jar. Press the plant material to recover the last of the liquid.
- Evaporate the ethanol outdoors or under a hood with gentle heat from a hot plate or a water bath. Never use a gas stove or an open flame.
- Purge until bubbles stop and the oil no longer smells of alcohol. A thin film that holds its shape when the jar cools is a sign the purge is done.
- Draw the warm oil into a glass syringe and store it in a cool, dark place.
Safety, law, and dosing checks
Solvent vapor is the main hazard. A closed room with a pilot light, a water heater, or a sparking appliance can ignite ethanol or isopropyl vapor. Work outside or in a space built for solvent work, wear nitrile gloves and eye protection, and keep a fire extinguisher within reach.
- Law: cannabis remains illegal under U.S. federal law. Home extraction is allowed in some states and banned in others, and some states restrict solvent type or quantity.
- Testing: commercial labs can screen for residual solvent, pesticides, and potency. Home batches carry none of that data.
- Dose: RSO is potent. A starting dose is about the size of a half grain of rice, and new users should wait two hours before adding more.
- Storage: glass syringes and amber jars beat plastic, which can leach into the oil.
Which route to pick
If your goal is a clean, repeatable batch and you have outdoor space, the cold ethanol quick wash wins. If ethanol is out of reach, expect a harder purge and a lower-quality result from isopropyl. If solvent handling is a hard no, a rosin press or an infused oil gives you a usable product with a different potency profile.