How to Make RSO (Rick Simpson Oil): Complete Extraction Guide

RSO oil, also known as Rick Simpson Oil, is a full-spectrum cannabis extract made by dissolving dried flower in 190-proof ethanol at a 750 mL per ounce ratio (roughly 3 cups per ounce of flower). The traditional Rick Simpson method used 1 gallon per ounce, but that volume of ethanol creates unnecessary fire risk during evaporation. 750 mL extracts just as effectively with half the solvent to purge, filtering the plant material, and evaporating the solvent at 140-160F until a thick, dark oil remains. Typical yield: 3-5 grams of RSO per ounce of flower at 20% THC input. Final potency ranges from 50-70% total cannabinoids with 2-8% terpene retention. The process takes 4-8 hours from start to finish. RSO differs from distillate because it retains the full chemical profile: cannabinoids, terpenes, flavonoids, chlorophyll, and plant waxes that contribute to the entourage effect.

What Is RSO (Rick Simpson Oil)?

RSO, or Rick Simpson Oil, is a full-spectrum cannabis extract made through ethanol extraction. Unlike concentrates that target isolated cannabinoids, RSO retains the full chemical profile of the plant: cannabinoids, terpenes, flavonoids, and other bioactive compounds. The result is a dark, viscous oil with a tar-like consistency that represents one of the most complete extractions you can produce from cannabis or hemp flower.

The process itself is straightforward, but the chemistry behind it matters. Ethanol is a polar solvent, meaning it pulls a broad range of compounds from plant material, including chlorophyll, waxes, and lipids. This is what gives RSO its characteristic dark color and full-bodied chemical profile. Understanding solvent polarity and its effect on extraction selectivity is critical to producing quality RSO consistently.

Equipment and Materials You Need

Before starting, gather the following:

• Cannabis or hemp flower: 1 ounce (28g) minimum. Higher quality input produces higher quality output.
• Food-grade ethanol (190 proof or higher): Everclear is the most accessible option. You need roughly 1 gallon per ounce of flower.
• Two large glass or ceramic mixing bowls
• Wooden spoon or silicone spatula for stirring
• Cheesecloth or fine mesh strainer
• Unbleached coffee filters for secondary filtration
• Rice cooker or double boiler for solvent evaporation
• Plastic syringes (no needle) for dosing and storage
• Ventilation: Work outdoors or in a well-ventilated area. Ethanol vapor is flammable.

Safety note: Never use an open flame near ethanol. Use electric heating elements only. Ethanol has a flash point of approximately 16.6°C (62°F), which means it can ignite at room temperature in the presence of a spark or open flame.

Step-by-Step RSO Extraction Process

Step 1: Decarboxylation (Optional Pre-Step)

If you want your RSO to be orally active without further heating, decarboxylation converts THCA to THC and CBDA to CBD. Spread your flower on a baking sheet lined with parchment paper and bake at 240°F (115°C) for 40 minutes. Some producers skip this step because the solvent evaporation phase generates enough heat to partially decarboxylate the extract. However, pre-decarbing ensures complete conversion and more predictable potency.

Step 2: First Ethanol Wash

Place your flower in a large glass bowl and pour enough ethanol to fully submerge the material, plus about an inch above. Stir gently for 3 to 5 minutes. This first wash extracts the majority of the cannabinoids and terpenes. Do not over-agitate or soak for extended periods. Longer contact time pulls more chlorophyll, waxes, and lipids, which darken the oil and reduce purity.

Step 3: Strain and Filter

Pour the ethanol solution through cheesecloth into a second clean bowl, squeezing gently to recover as much liquid as possible. For cleaner RSO, run the filtered liquid through an unbleached coffee filter. This removes fine plant particulate but does not remove dissolved chlorophyll or waxes.

Step 4: Second Wash (Optional)

You can perform a second wash on the same plant material to recover residual cannabinoids. Add fresh ethanol, stir for another 2 to 3 minutes, and strain again. Combine the first and second wash liquids. The second wash typically yields 15 to 20 percent additional cannabinoids but also extracts more undesirable compounds. Many producers keep the first and second wash separate, using the first wash for oral RSO and the second wash for topical applications.

Step 5: Solvent Evaporation

This is where most mistakes happen. Pour the filtered ethanol solution into a rice cooker and set it to the lowest heat setting. The rice cooker provides consistent, gentle heat that keeps temperatures below ethanol’s boiling point of 173°F (78.4°C) while still driving off the solvent efficiently. As the ethanol evaporates, the liquid volume decreases and the color darkens.

Never allow the temperature to exceed 290°F (143°C). Cannabinoid degradation accelerates above this threshold, converting THC to CBN and destroying terpenes. A rice cooker’s built-in thermal switch typically prevents overheating, which is why it is the preferred tool for this step.

The process takes 3 to 4 hours depending on the volume of ethanol. The oil is ready when it stops bubbling and becomes a thick, dark, viscous liquid. Small bubbles indicate residual solvent still evaporating. Wait until all bubbling stops completely.

Step 6: Collection and Storage

While the RSO is still warm and fluid, draw it into plastic oral syringes using the plunger. Once cooled, RSO becomes extremely thick and difficult to work with. Store filled syringes in a cool, dark place. RSO remains stable for months when kept away from heat, light, and oxygen. Refrigeration extends shelf life but makes the oil harder to dispense. Warming the syringe briefly under hot water restores workability.

Understanding RSO Potency and Composition

Well-made RSO from high-quality cannabis flower typically tests between 50 and 70 percent total cannabinoids. This is lower than ethanol shatter or distillate because RSO retains chlorophyll, lipids, and plant waxes that dilute the cannabinoid concentration. However, many users and patients prefer RSO specifically because of this full-spectrum profile.

The entourage effect, where cannabinoids and terpenes work synergistically, is maximized in full-spectrum extracts like RSO. This is the primary reason RSO has remained popular despite the availability of more refined concentrates. The trade-off is simple: higher purity concentrates isolate specific compounds, while RSO preserves the whole-plant chemistry.

Common Mistakes and How to Avoid Them

• Soaking too long: Extended ethanol contact (over 5 minutes) pulls excessive chlorophyll and waxes. Keep wash times short.
• Using isopropyl alcohol: Isopropyl (rubbing alcohol) contains denaturants and is not food-safe. Always use food-grade ethanol. If 190-proof Everclear is unavailable in your state, 151-proof works but yields a slightly less potent product due to water content.
• Overheating during evaporation: Temperatures above 290°F degrade cannabinoids. Use a rice cooker or double boiler with temperature monitoring.
• No ventilation: Ethanol vapor is heavier than air and accumulates at ground level. Always work in a well-ventilated area, preferably outdoors.
• Skipping filtration: Unfiltered RSO contains plant particulate that affects taste and consistency. Double-filter through cheesecloth and coffee filters.

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RSO vs. Other Cannabis Extracts

RSO occupies a unique position among cannabis extracts. Here is how it compares:

• RSO vs. Distillate: Distillate is a refined, high-potency extract (85 to 95 percent cannabinoids) produced through short path or wiped film distillation. RSO is unrefined and retains the full plant profile. Distillate is nearly flavorless; RSO has a strong, earthy, sometimes bitter taste.
• RSO vs. CO2 Oil: CO2 extraction produces a cleaner extract with better terpene preservation, but it requires expensive equipment ($50,000+). RSO can be made at home for under $50 in materials.
• RSO vs. BHO: Butane extracts target trichome heads and produce lighter-colored concentrates (shatter, wax, live resin). RSO extracts the whole plant, producing a darker, more complete extract.
• RSO vs. Tincture: Both use ethanol, but tinctures retain the solvent as the delivery vehicle. RSO evaporates the ethanol completely, leaving only the concentrated oil.

RSO Extraction Parameters by Method

Bottom line: 190-proof ethanol or Everclear are the only solvents that should be used for RSO intended for human consumption. Isopropyl and naphtha leave toxic residuals that cannot be fully purged at home without analytical testing to confirm safety.

RSO vs Other Cannabis Extracts: What You Actually Get

RSO’s advantage over distillate is the entourage effect. The retained terpenes, flavonoids (including cannflavins A and B, which showed 30x greater inhibition of prostaglandin E2 than aspirin in one specific in-vitro assay (Barrett et al., 1986, human rheumatoid synovial cells). This does not mean 30x more potent in the body, as in-vivo bioavailability and dose-response differ substantially), and minor cannabinoids (CBN, CBC, CBG) produce a broader therapeutic profile than isolated THC. RSO’s disadvantage is taste: the chlorophyll and plant waxes make it bitter and difficult to consume without capsules or food.

RSO Dosing Protocol: Standard Titration Schedule

For the complete pharmacokinetics guide including carrier oil bioavailability comparisons, sublingual vs oral absorption data, and dosing failure diagnostics, see our dedicated RSO Dosing Protocol and Carrier Oil Science article.

RSO Extraction Failures: Diagnosis and Fixes

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RSO Tincture Recipe: Turning RSO into a Sublingual Oil

One of the most common questions from first-time RSO makers: can you dissolve RSO into a carrier oil to make a tincture? Yes. And there are good reasons to do it beyond convenience.

RSO straight from the syringe is thick, sticky, and difficult to dose precisely. Dissolving it into MCT oil (fractionated coconut oil) converts it into a sublingual tincture with two practical advantages: precise dosing with a graduated dropper, and faster onset. Sublingual absorption bypasses first-pass liver metabolism, meaning the cannabinoids reach systemic circulation in 15-30 minutes instead of the 60-90 minute window for oral ingestion. The tradeoff is lower total bioavailability for some compounds that benefit from hepatic conversion (specifically, THC converting to the more potent 11-hydroxy-THC in the liver).

Basic RSO Tincture Protocol

Start with 1 gram of RSO and 30 mL of MCT oil. That gives you roughly 20-25 mg of THC per mL (assuming your RSO tests at 60-70% total cannabinoids). Warm the MCT oil to 60C (140F) in a glass container, add the RSO, and stir until fully dissolved. Do not exceed 70C or you begin losing volatile terpenes. Transfer to an amber glass dropper bottle and store in a cool, dark place. Shelf life: 6-12 months when stored properly.

For lower-dose tinctures (5-10 mg/mL), use 60 mL of MCT oil per gram of RSO. For higher-concentration tinctures (40-50 mg/mL), reduce to 15 mL of MCT oil. The RSO dissolves more readily in warm oil, but do not microwave it. Use a water bath or low-heat plate.

MCT oil is the preferred carrier because its medium-chain fatty acids (C8 and C10 caprylic and capric acid) have higher lymphatic absorption than long-chain triglycerides found in olive oil or hemp seed oil. This means more cannabinoid reaches systemic circulation rather than being metabolized on first pass. If you want the hands-on walkthrough for dialing in carrier oil selection and dosing math, that is exactly what we built extractiontraining.com for.

Carrier Oil Comparison for RSO Tinctures

MCT is the default carrier for a reason, but it is not the only option. The carrier oil changes how the cannabinoids absorb, how fast they hit, and how long the tincture lasts on the shelf. Here is what actually matters.

The difference between MCT and olive oil is not subtle. MCT’s C8 and C10 chains are short enough to enter lymphatic circulation directly, bypassing hepatic first-pass metabolism. That means more THC reaches the bloodstream as THC rather than being converted to 11-hydroxy-THC in the liver. For patients who want the specific effects of delta-9 THC rather than its liver metabolite, MCT is the only carrier that makes pharmacological sense.

RSO Tincture Dosing Reference

Every RSO batch is different. These calculations assume 60-70% total cannabinoids in your RSO, which is typical for a well-made ethanol extraction from 20-25% THC flower. Adjust based on your actual potency if you have lab results.

At concentrations above 65 mg/mL, the RSO may not fully dissolve in MCT oil at room temperature. Warm the mixture to 60C and stir for 5 minutes. If the oil remains cloudy after cooling, reduce the RSO-to-oil ratio. Cloudy tincture means undissolved cannabinoids sitting at the bottom of the bottle, which means inconsistent dosing.

Flavoring and Shelf Life

RSO tinctures taste like concentrated cannabis. There is no avoiding it entirely. Food-grade peppermint oil (2-3 drops per 30 mL) is the most effective masking agent. Citrus oils work but oxidize faster. Vanilla extract adds sweetness without competing with the terpene profile. Add flavoring after the RSO dissolves completely, not during heating.

Shelf life depends on the carrier and storage. MCT tinctures stored in amber glass at room temperature last 12-18 months. Hemp seed oil tinctures degrade in 3-6 months due to polyunsaturated fat oxidation. Refrigeration extends all tinctures by 30-50%. The degradation you are watching for is not the carrier going rancid (you will smell that). It is the cannabinoids oxidizing: THC converts to CBN at a rate of approximately 5% per year at room temperature, faster with light or heat exposure.

THCA RSO: Making Non-Psychoactive Rick Simpson Oil

Standard RSO starts with decarboxylation, converting THCA to THC before extraction. THCA RSO skips that step entirely. The result is an oil where 40-70% of the cannabinoid content remains as THCA in its acid form: non-psychoactive, anti-inflammatory, and increasingly used by patients who need cannabinoid therapy without intoxication.

THCA decarboxylates to THC at approximately 105C (220F) with a half-life of about 30 minutes at that temperature. Below 80C (176F), the conversion rate drops to less than 2% per hour. That 25-degree window between 80C and 105C is everything. Every step of THCA RSO production is about staying below that line.

Some producers skip the flower entirely and start with full-melt bubble hash as the starting material. Ice water extraction pre-separates trichome heads from plant matter, so the resulting RSO has higher cannabinoid concentration and less chlorophyll. The tradeoff is lower total yield per pound of flower processed.

THCA RSO Extraction Protocol

The process is identical to standard RSO with three critical modifications: no decarboxylation, cold solvent contact, and low-temperature evaporation.

Step 1: Skip decarboxylation. Use raw, unheated cannabis flower. Do not oven-treat, microwave, or sous vide the material. The flower should be dried and cured normally (target water activity 0.55-0.60), but never exposed to temperatures above 80C during any pre-processing.

Step 2: Cold ethanol wash. Chill 190-proof ethanol to -20C (-4F) or colder before contact. Freezer temperature is acceptable; dry ice bath (-40C) is better. Cold ethanol is critical for two reasons: it minimizes chlorophyll and wax co-extraction (cleaner oil), and it prevents any thermal conversion of THCA during the wash. Contact time: 3 minutes maximum. One wash only. A second wash at cold temperature extracts diminishing cannabinoids but increasing undesirables.

Step 3: Filter at cold temperature. Strain through a 25-micron mesh, then through an unbleached coffee filter. Keep the solution cold during filtration. If it warms above 15C during filtering, you have not compromised the THCA, but you will pull more chlorophyll into the final product.

Step 4: Low-temperature evaporation. This is where most THCA RSO fails. A rice cooker runs at 100C, which is close enough to the 105C decarboxylation threshold to convert 15-30% of your THCA to THC during a 3-hour evaporation. Instead, use a vacuum oven or rotary evaporator. Target: evaporate ethanol at 40-50C under vacuum (25-29 inHg). At 45C and full vacuum, ethanol boils off efficiently while THCA conversion stays below 3%. If you do not have vacuum equipment, use a double boiler at 60C maximum, accept a longer evaporation time (6-10 hours), and accept 5-8% THCA-to-THC conversion.

Step 5: Nitrogen blanket and storage. Once the ethanol is evaporated, purge the headspace of your storage container with food-grade nitrogen gas before sealing. THCA oxidizes to CBNA (cannabinolic acid) when exposed to oxygen, degrading potency over weeks. Amber glass syringes or vials with nitrogen headspace, stored at 4C (refrigerator temperature), preserve THCA content for 6-12 months. Without nitrogen blanketing at room temperature, expect 10-15% THCA loss per month from oxidation alone.

THCA RSO vs Standard RSO

If your lab results come back showing THCA:THC lower than 85:15, your evaporation temperature was too high. The fix is lower temperature, longer time, and ideally vacuum. There is no way to convert THC back to THCA once decarboxylation has occurred.

Frequently Asked Questions

How long does it take to make RSO at home?

The full process takes approximately 4 to 6 hours from start to finish. The ethanol washes and filtration take about 30 minutes. Solvent evaporation in a rice cooker takes 3 to 4 hours depending on volume. If you include a decarboxylation pre-step, add another 40 minutes of oven time.

What is the best solvent for making RSO?

Food-grade ethanol at 190 proof (95% concentration) is the standard. Everclear is the most widely available option. Never use isopropyl alcohol, denatured alcohol, or methanol. These contain toxic additives that cannot be fully removed during evaporation and pose serious health risks.

How much RSO does one ounce of flower produce?

One ounce (28 grams) of quality cannabis flower typically yields 3 to 5 grams of RSO, depending on the starting material’s cannabinoid content and how thoroughly you wash. This represents roughly a 10 to 18 percent return by weight. Higher potency flower yields more concentrated RSO.

Does RSO need to be decarboxylated?

If you plan to consume RSO orally (under the tongue, in capsules, or mixed into food), decarboxylation is recommended. Raw THCA is not psychoactive; it must be converted to THC through heat. The solvent evaporation step provides some decarboxylation, but it is not complete or consistent. Pre-decarbing at 240°F for 40 minutes before extraction ensures full activation.

Can you make RSO from hemp flower?

Yes. Hemp-derived RSO follows the exact same process. The resulting oil will be high in CBD rather than THC, with total cannabinoid content typically between 40 and 60 percent. Hemp RSO is legal under the 2018 Farm Bill provided the final product contains less than 0.3% delta-9 THC by dry weight.

Is RSO the same as cannabis oil?

“Cannabis oil” is a broad term that can refer to any oil derived from cannabis, including distillate, CO2 oil, MCT-based tinctures, and RSO. RSO specifically refers to the full-spectrum ethanol extract made using the Rick Simpson method. The key difference is that RSO retains the complete chemical profile of the plant, while most commercial cannabis oils are refined to isolate specific cannabinoids.

How should RSO be stored for maximum shelf life?

Store RSO in airtight plastic syringes or glass containers in a cool, dark location. Exposure to heat, light, and oxygen degrades cannabinoids over time, converting THC to CBN and reducing potency. Properly stored RSO remains effective for 6 to 12 months. Refrigeration extends shelf life further but thickens the oil. Run the syringe under warm water for 30 seconds before dispensing refrigerated RSO.

Why is RSO so dark compared to other extracts?

RSO’s dark color comes from chlorophyll, lipids, and plant waxes that ethanol extracts along with cannabinoids and terpenes. These compounds are not present in more refined extracts like distillate or BHO shatter, which use either non-polar solvents or post-processing steps (winterization, filtration) to remove them. The dark color is not an indicator of quality; it simply reflects the full-spectrum nature of the extraction.

How is RSO made?

RSO is made by soaking dried cannabis flower in cold food-grade ethanol (190 proof), filtering the plant material out, and then slowly evaporating the solvent until only a thick, dark, full-spectrum oil remains. The standard process uses two 3-minute ethanol washes at -20C or colder to minimize chlorophyll and wax co-extraction. After filtering through a 25-micron mesh, the ethanol is evaporated in a rice cooker or hot plate at 70-80C until bubbling stops, then vacuum purged at 40-50C to remove the last 500-1,000 ppm of residual solvent. One ounce of flower typically yields 3 to 5 grams of finished RSO at 50 to 70 percent total cannabinoids.

Can you use Everclear to make RSO?

Everclear (190 proof, 95% ethanol) is the go-to solvent for RSO production. It is food-grade, widely available, and evaporates cleanly without leaving toxic residues. The 5% water content actually helps extract a broader range of polar compounds like flavonoids and phenolic acids that pure ethanol would miss. If Everclear is not available in your state, look for any food-grade ethanol at 190 proof or higher. Avoid 151-proof versions if possible. The lower ethanol concentration pulls more water-soluble chlorophyll and produces a harsher tasting oil with a heavier green color.

How many washes should you do when making RSO?

Two washes is the standard. The first wash (3 minutes, cold ethanol at -20C) pulls 70 to 80 percent of the available cannabinoids with minimal chlorophyll. The second wash (another 3 minutes) recovers most of the remaining 20 to 30 percent. A third wash is possible but the returns drop sharply. You are mostly pulling chlorophyll, lipids, and waxes at that point. The combined first and second wash extracts will have a different color profile. The first wash produces a golden amber oil. The second wash is darker and more plant-forward. Some producers keep them separate and use the first wash for oral dosing and the second wash for topicals.

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What is THCA RSO?

THCA RSO is Rick Simpson Oil extracted from raw, undecarboxylated cannabis, preserving 40-70% of the cannabinoid content as THCA rather than converting it to psychoactive THC. THCA decarboxylates to THC at 105C (220F) with a half-life of about 30 minutes. Making THCA RSO requires cold ethanol (-20C or colder), low-temperature evaporation (50C max under vacuum), and nitrogen-blanketed storage to prevent oxidation. See the full THCA RSO protocol above for the step-by-step SOP with temperature controls and failure diagnostics.

Can You Turn RSO into a Tincture?

Dissolve 1 gram of RSO in 10 to 30 mL of MCT oil depending on desired potency. Warm the carrier oil to 60C (140F) and stir until the RSO dissolves completely. MCT oil is the best carrier because medium-chain fatty acids (C8 and C10) bypass first-pass liver metabolism through lymphatic absorption, improving sublingual bioavailability by 3 to 5 times compared to long-chain carriers like olive oil. For a deeper breakdown of carrier oil pharmacokinetics, see our RSO dosing protocol guide. Store in amber glass dropper bottles at room temperature for 6 to 12 months shelf life.

What is the Difference Between RSO and FECO?

RSO and FECO (Full Extract Cannabis Oil) are the same product made by the same ethanol extraction process. FECO is the technically accurate name. RSO is named after Rick Simpson who popularized the method in the early 2000s. Some producers call grain alcohol extracts FECO and naphtha extracts RSO, but modern practice uses food-grade ethanol exclusively for both. The chemistry, cannabinoid profile, and therapeutic applications are identical.