¶ Ethanol Extraction
Ethanol (ethyl alcohol) extraction is one of the oldest and most widely used methods for producing cannabis concentrates. Food-grade ethanol is an efficient, versatile, and relatively safe solvent that dissolves cannabinoids, terpenes, and a broad range of plant compounds. It is the dominant extraction method for producing cannabis-infused edibles, tinctures, and large-scale cannabinoid isolates.
¶ Why Ethanol?
Ethanol offers several advantages that make it a popular extraction solvent:
| Advantage | Description |
|---|---|
| Food-grade availability | Ethanol is widely available in food-grade and laboratory-grade purity |
| Safety | Much safer than hydrocarbons; not prone to explosion under normal conditions |
| Efficiency | Effectively dissolves cannabinoids and terpenes |
| Scalability | Works for small-scale home extraction and industrial production |
| Regulatory acceptance | Generally recognized as safe (GRAS) by the FDA for food processing |
| Cost | Relatively inexpensive compared to CO2 equipment or hydrocarbon systems |
| Universal solvent | Extracts a broad range of compounds including minor cannabinoids |
| Established infrastructure | Rotary evaporators, filters, and recovery equipment are widely available |
¶ Process Overview
The general ethanol extraction process follows these steps:
¶ Step 1: Prepare Material
Cannabis flower or trim is prepared for extraction:
- Dried material -- Standard dried and cured flower or trim, ground to moderate consistency
- Fresh frozen material -- For Live Resin production, material is frozen immediately after harvest
- Decarboxylated material -- If the target product requires activated cannabinoids (for edibles, tinctures), material is heated to convert THCA to THC before extraction
¶ Step 2: Chill Material and Ethanol
Temperature is critical for ethanol extraction quality:
| Temperature | Effect |
|---|---|
| Room temperature | Maximum extraction but also maximum chlorophyll, waxes, and water-soluble contamination |
| Refrigerated (35-40 degrees F / 2-4 degrees C) | Moderate extraction with reduced chlorophyll |
| Frozen (-40 to 0 degrees F / -40 to -18 degrees C) | Cleanest extraction; ethanol's selectivity is reduced at low temperatures, extracting fewer undesirable compounds |
💡 Freezing both the plant material and the ethanol before extraction significantly reduces the co-extraction of chlorophyll, lipids, and water-soluble compounds, producing a cleaner crude extract.
¶ Step 3: Wash/Extraction
The chilled ethanol is combined with the prepared cannabis material:
- Short wash (30 seconds to 3 minutes) -- Produces cleaner extract with less chlorophyll and waxes; preferred for QWET (Quick Wash Ethanol Technique)
- Long wash (30 minutes to several hours) -- Extracts more total cannabinoids but also more chlorophyll, lipids, and water-soluble compounds; used for full-extraction processes
The ratio of ethanol to plant material typically ranges from 1:3 to 1:5 (plant material weight to ethanol volume).
¶ Step 4: Filter
The ethanol solution (miscella) is separated from the plant material through filtration:
| Filtration Method | Description | Effectiveness |
|---|---|---|
| Coffee filters | Simple gravity filtration through paper coffee filters | Good for small-scale; slow |
| Micron filter bags | Mesh bags (25-200 micron) | Fast; good for larger volumes |
| Buchner funnel with filter paper | Vacuum-assisted filtration | Efficient; laboratory standard |
| Centrifugal separation | Spinning to separate solids | Industrial scale |
¶ Step 5: Evaporate/Recover Ethanol
The ethanol must be removed from the extract, leaving behind concentrated cannabinoids and other dissolved compounds.
| Recovery Method | Description | Scale | Cost | |
|---|---|---|---|---|
| Open-air evaporation | Letting ethanol evaporate naturally | Very small scale; not recommended | Free (but wastes solvent) | |
| Heat and fan | Gentle warming with ventilation | Small scale | Low | |
| Rotary evaporator (rotovap) | Vacuum-assisted evaporation at low temperature with solvent recovery | Lab to commercial | $2,000-$15,000+ | |
| Distillation | Boiling and condensing ethanol for recovery | Commercial | $5,000-$50,000+ | |
| Falling film evaporator | Continuous thin-film evaporation | Industrial | $20,000-$100,000+ | info |
Ethanol recovery is both economically important and environmentally responsible. Professional systems recover 90-98% of the ethanol used, making it cost-effective to reuse the solvent across multiple batches.
¶ Step 6: Winterization (If Needed)
Ethanol extracts lipids, fats, and waxes from cannabis plant material -- especially when using warm ethanol or long wash times. These compounds must be removed for many applications (particularly vape cartridges).
Winterization process:
- Dissolve the crude extract in warm ethanol
- Place the solution in a freezer at -40 to 0 degrees F (-40 to -18 degrees C) for 24-48 hours
- During this time, lipids and waxes solidify and precipitate out of solution
- Filter the cold solution through filter paper or a micron filter to remove the precipitated fats/waxes
- Recover the ethanol from the filtered solution as described above
💡 Short, cold washes (QWET technique) naturally extract fewer lipids and waxes, reducing or eliminating the need for winterization.
¶ QWET (Quick Wash Ethanol Technique)
QWET is a small-scale ethanol extraction method optimized for cleanliness and simplicity. It is one of the most accessible extraction methods for informed adults in jurisdictions where it is legal.
¶ QWET Step-by-Step
Step 1: Decarboxylate (Optional)
If activated cannabinoids are desired (for tinctures, edibles), decarboxylate the material at 220-240 degrees F (104-116 degrees C) for 30-45 minutes. Skip this step if preserving acidic cannabinoids (THCA, CBDA) is desired.
Step 2: Freeze
Place the cannabis material and food-grade ethanol (190-proof / 95% ethanol) in the freezer separately for at least 12-24 hours. Both should be at the same temperature.
Step 3: Wash
Combine the frozen material and ethanol in a sealed jar. Agitate gently for 30 seconds to 3 minutes.
Step 4: Filter
Strain through a coffee filter or fine mesh into a clean container. The resulting liquid should be green to amber in color.
Step 5: Evaporate
Allow the ethanol to evaporate in a well-ventilated area (never near an open flame -- ethanol vapor is flammable). The remaining oil is the extracted concentrate.
Step 6: Store
Store the concentrate in an airtight glass container in a cool, dark place.
¶ Temperature and Wash Time Effects
The combination of temperature and wash time dramatically affects extract composition:
| Temperature | Wash Time | Chlorophyll | Lipids/Waxes | Cannabinoids | Terpenes | Overall Quality |
|---|---|---|---|---|---|---|
| Frozen (-40 degrees F) | 30 sec - 3 min | Very low | Very low | Moderate | High | Excellent (QWET) |
| Frozen | 5-15 min | Low | Low | High | High | Very Good |
| Refrigerated | 1-5 min | Moderate | Moderate | High | Moderate | Good |
| Room temp | 30 sec - 3 min | Moderate | High | High | Moderate-High | Moderate |
| Room temp | 15+ min | High | Very high | Very high | Low-Moderate | Lower (requires winterization) |
¶ Advantages of Ethanol Extraction
| Advantage | Description |
|---|---|
| Safe solvent | Ethanol is much safer to handle than hydrocarbons; does not pool and explode |
| Food-grade | GRAS designation; acceptable for food and pharmaceutical applications |
| Efficient | Extracts a broad spectrum of cannabinoids and terpenes |
| Scalable | From kitchen-jar QWET to industrial falling-film evaporators |
| Cost-effective | Ethanol is inexpensive and recoverable for reuse |
| Versatile | Suitable for edibles, tinctures, vape cartridges, isolates, and more |
| Regulatory acceptance | Widely permitted in legal cannabis markets |
¶ Disadvantages and Challenges
| Disadvantage | Description |
|---|---|
| Chlorophyll extraction | Ethanol is one of the few solvents that dissolves chlorophyll, giving extracts a green color and grassy taste |
| Water-soluble extraction | Ethanol dissolves water-soluble compounds (sugars, proteins) that are undesirable in concentrates |
| Winterization required | Most applications require an additional step to remove fats and waxes |
| Large solvent volumes | Ethanol extraction requires significantly more solvent volume compared to hydrocarbon or CO2 methods |
| Flammability | Ethanol is flammable (though much less dangerous than butane/propane); requires ventilation and no open flames |
| Denatured ethanol issues | Some ethanol is denatured with bitter or toxic additives to avoid alcohol taxation; these additives contaminate the extract |
| Terpene loss | Ethanol's volatility during recovery strips some volatile terpenes |
¶ Denatured Ethanol Warning
🚨 Danger Some ethanol is "denatured" -- additives are mixed in to make it undrinkable, avoiding beverage alcohol taxes. Common denaturants include methanol (toxic), isopropyl alcohol, denatonium benzoate (extremely bitter), and other chemicals. Always use food-grade or lab-grade undenatured ethanol for extraction. Check the product specification before purchasing.
¶ Commercial Ethanol Extraction Systems
Large-scale commercial ethanol extraction uses specialized equipment:
| System | Description | Throughput | Cost |
|---|---|---|---|
| Centrifugal extraction | Material and ethanol are mixed and separated by centrifugal force; continuous process | 100+ lbs/hour | $50,000-$200,000+ |
| Closed-loop ethanol | Similar to hydrocarbon CLE but designed for ethanol; solvent is recovered and recycled | 50-200 lbs/batch | $20,000-$100,000 |
| Falling film evaporator | Thin-film ethanol recovery at scale; primary solvent recovery system | Industrial | $20,000-$100,000+ |
| Decarboxylation + extraction integrated | Combines decarboxylation and extraction in one system | High | $100,000+ |
¶ Decarboxylation for Ethanol Extracts
Ethanol extracts -- whether produced as QWET, full-spectrum crude oil, or RSO -- contain cannabinoids in their acidic forms and must be decarboxylated before use in edibles or tinctures intended to deliver activated THC or CBD.
¶ Decarboxylation Process
For ethanol-extracted crude oil/RSO:
- Place extract in a heat-safe glass container
- Heat at 220-240 degrees F (104-116 degrees C) for 30-60 minutes
- RSO and full-spectrum ethanol extracts are thick and viscous, requiring thorough heating to ensure complete decarboxylation throughout the mass
- The extract will bubble as CO2 is released -- this is the decarboxylation reaction in progress
For material decarbed before extraction:
If the plant material was decarboxylated prior to ethanol extraction (as noted in the QWET process), the resulting extract will already contain activated cannabinoids and may not require additional decarboxylation. However, pre-extraction decarboxylation is rarely 100% complete, so a brief post-extraction decarb (15-20 minutes at 220 degrees F) ensures full activation.
ℹ️ Decarboxylation math for RSO/ethanol extract: 1 gram of RSO at approximately 70% total cannabinoids contains ~700mg of cannabinoids. If approximately 70% of those are THC (post-decarb), that equals roughly 490mg THC -- or approximately 49 standard 10mg edible servings from a single gram.
This is why precise measurement is essential. A common kitchen scale is not precise enough for individual dosing -- use a milligram scale or dilute the extract in a known volume of carrier oil for accurate measurement.
See Decarboxylation for complete temperature and time guidance, including how to calculate decarboxylation percentage and optimize for specific cannabinoid ratios.
¶ Common Products from Ethanol Extraction
Ethanol-extracted cannabis is the starting material for many products:
| Product | Description |
|---|---|
| Tinctures -- See Tinctures & Sublingual | Ethanol extracts diluted to specific cannabinoid concentrations in dropper bottles |
| Edibles -- See Edibles | Ethanol extract infused into food products or used as a direct ingredient |
| RSO (Rick Simpson Oil) | High-dose full-extract ethanol concentrate; typically dark, thick, and full-spectrum |
| Distillate feedstock | Ethanol crude is the starting material for Distillate production |
| Isolate production | Further refinement of ethanol extract produces THCA, CBD, and other cannabinoid isolates |
| Vape cartridge oil | After winterization and distillation, ethanol extract can be formulated for vape cartridges |
¶ Navigation
- Extraction Overview -- All extraction methods
- BHO/PHO -- Hydrocarbon extraction
- CO2 Extraction -- Supercritical CO2 extraction
- Distillate -- Refined from ethanol crude
- Tinctures -- Ethanol-based tincture products
- Edibles -- Products made from ethanol extracts
- Harm Reduction -- Safety guidelines
This page provides educational information about ethanol extraction. Always comply with applicable laws and regulations regarding cannabis possession, processing, and solvent use. Ethanol vapor is flammable -- ensure adequate ventilation and avoid ignition sources during evaporation.