- Black/dark usually means more plant compounds (chlorophyll/waxes) and/or more heat during evaporation — not “more THC.”
- Amber/gold often means colder/shorter contact and cleaner filtration — many people mistake this for “weaker.”
- Green is chlorophyll pickup (longer soak, warmer solvent, or minimal filtration). Taste can be harsher.
- If you care about a reliable experience, stop arguing color and calculate mg per serving.
What controls RSO color (the real variables)
RSO looks different when the process changes. The biggest drivers are:
- Extraction temperature (cold pulls less chlorophyll; warm pulls more).
- Contact time (quick wash vs long soak).
- Agitation (shaking harder extracts more plant material).
- Filtration (coffee filter vs fine filtration vs multiple passes).
- Evaporation heat (overheating darkens oil and can degrade terpenes/cannabinoids).
- Starting material (older, oxidized flower often yields darker oil).
Two people can start with the same flower and end with different colors. Both can be potent. One can also be a sloppy, harsh mess.
Color meanings (common outcomes)
Jet black
Usually: hotter evaporation and/or heavy pickup of plant compounds. Can be potent, but often tastes more “planty” and can be rougher for some stomachs.
Dark brown / coffee
Classic outcome from moderate control. Often balanced strength with some plant character. Not automatically bad.
Amber / honey / gold
Often: colder/shorter contact + cleaner filtration. Cleaner taste. Do not assume it is weak — measure it.
Green
Chlorophyll pickup (long soak, warm solvent, minimal filtration). Not automatically unsafe, but commonly harsher and more bitter.
Color is not a potency test
Potency depends on your starting flower and how efficiently you extracted — plus losses during transfer/filtration and any degradation from heat/light.
- If you used weak starting material, dark oil won’t magically become strong.
- If you used great flower and controlled the process, lighter oil can still hit hard.
- If you overheated during evaporation, you can darken oil and reduce quality at the same time.
How to standardize your RSO (repeatable batches)
If you want consistent oil, lock the variables:
- Pick one method (quick wash vs soak) and stick to it for 5 batches before changing anything.
- Keep temperature consistent (cold is easier to repeat).
- Use the same agitation pattern and time every batch.
- Use the same filtration stack every batch (and note how long it takes to pass).
- Evaporate gently. Darkening from overheating is a self-own.
- Store oil away from light/heat. Oxidation changes color over time.
Safety and legality (don’t freestyle)
RSO commonly involves flammable solvents and fumes. Treat it like a fire hazard because it is one.
- Ventilation matters. No open flames. No sparks. No “kitchen science” ego.
- Use appropriate PPE and follow local laws.
- If you can’t do it safely, don’t do it.
Sources and what they support
Color is mostly pigments, waxes, and oxidation. It is not a potency meter. These references explain why alcohol extracts often come out dark and how pigments and oxidation show up.
- Processing and extraction methods of medicinal cannabis (Lazarjani et al., 2021) — overview of extraction methods and notes that ethanol can co-extract pigments such as chlorophyll.
- The Evolution of Ethanol Extraction Methods in Cannabis (Cannabis Science and Technology) — explains why crude ethanol extracts, including RSO-style products, are often dark due to chlorophyll co-extraction.
- Proper Cannabis and CBD Oil Filtration (ErtelAlsop) — describes pigment removal and why chlorophyll can make extracts bitter and unstable.
- Vapor Phase Terpenes Mitigate Oxidative Degradation of Inflorescence Cannabinoids (Bueno et al.) — shows oxidation and storage conditions can drive cannabinoid degradation, which can also darken products over time.
FAQ
Does darker RSO mean it is stronger?
Not necessarily. Darker oil often reflects chlorophyll/waxes or heat exposure. Potency depends on starting material and extraction efficiency.
Why did my RSO turn green?
Green usually means chlorophyll pickup from longer contact time, warmer extraction, heavier agitation, or lighter filtration.
Can RSO darken over time in storage?
Yes. Heat, light, and oxygen can darken oil over time even if it started lighter.
What’s the fastest way to avoid an accidental mega-dose?
Calculate mg per serving and start low. Edibles and oils can take longer to peak than people expect.
Next steps
- THC dosing calculator — Turn potency into mg per serving with conversion and loss factors.
- Gear Library (Extraction basics) — Practical tools and storage that reduce surprises.
- Why retail cannabis cannot be properly cured — Why starting material often explains the outcome.
- About HazeHack — What this site is and what it is not.