Last updated: October 2026
CBD is extracted by passing a solvent, usually supercritical CO₂ or food-grade ethanol, through dried, ground hemp flowers and leaves to dissolve the cannabinoids. The solvent is removed, then the crude extract is winterised to strip out waxes, distilled and, for broad spectrum, run through chromatography to take out THC before it is blended into a carrier oil.
All of this happens in specialist labs: extracting CBD at home is illegal in the UK. Below, the six methods compared in one table, what each refining step does, how isolate is made, what to check on a lab report and the UK rules.
Our CBD: every Evopure CBD oil and capsule uses broad spectrum CBD with 0% THC, made in the UK and third-party tested at ISO 17025 accredited labs. Start with our Broad Spectrum CBD Oil (CBD and MCT oil, nothing else), or request a batch report on our lab testing page.
CBD extraction methods compared
Almost all commercial CBD extract is made with supercritical CO₂ or ethanol. The other four methods are mainly used for cannabis concentrates abroad, essential oils or traditional home preparations.
| Method | How it works | Pros | Cons | Where it’s used |
|---|---|---|---|---|
| Supercritical CO₂ | Pressurised carbon dioxide dissolves cannabinoids, then turns back into a gas | No solvent left behind; non-flammable; tunable to target compounds | Expensive high-pressure equipment | Commercial CBD extract |
| Ethanol | Plant soaked in food-grade alcohol, which is then evaporated off and recovered | High yield; scales well to large batches | Pulls out chlorophyll and waxes, so needs more refining; flammable | Large batches of CBD extract |
| Hydrocarbon (butane, propane) | Liquefied gas solvents washed through the plant | Keeps aroma compounds (terpenes) well | Explosive; risk of solvent residue and wax carryover | Cannabis concentrates abroad |
| Olive oil infusion | Heated plant steeped in a carrier oil | Simple; safe, non-flammable solvent | Weak, can’t be concentrated, strength varies widely | Traditional home preparations |
| Steam distillation | Steam carries volatile compounds out of the plant | No chemical solvent | Inefficient for cannabinoids; heat can damage them | Hemp essential oil |
| Solventless (rosin, ice water, dry sieve) | Heat and pressure, or cold water and shaking, separate the resin glands | No solvent at all | Labour-intensive; some terpenes lost to heat | Small-batch concentrates, not CBD oils |
New to the terms? Our CBD glossary explains them in plain English.
The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication.
CO₂ vs ethanol extraction: which is better?
Both produce clean CBD extract when a specialist lab runs them properly, and both are used by reputable brands. The method matters less than how well the extract is refined afterwards and whether every batch is tested.
How CO₂ extraction works
Under high pressure and controlled temperature, carbon dioxide becomes “supercritical”, behaving partly like a liquid and partly like a gas. Pumped through ground hemp, it dissolves cannabinoids and terpenes. When the pressure drops, the CO₂ turns back into a gas and leaves the extract behind with no solvent residue. It’s the same principle used to decaffeinate coffee.
Reviews describe CO₂ as non-flammable, non-toxic and easy to remove, with low running costs once the equipment is in place. The trade-off is that raising the pressure makes CO₂ a stronger but less selective solvent, so operators balance yield against purity. The price of the equipment is why it is mostly used by large, specialist extractors.
How ethanol extraction works
Hemp is soaked in food-grade ethanol, the plant material is filtered out, and the ethanol is evaporated and recovered for the next batch. Cold ethanol pulls out fewer waxes. In comparison studies, ethanol gave the highest recovery of acidic cannabinoids such as CBDA. Its weakness is chlorophyll, which comes out too and makes the extract green and bitter. Stripping it with activated charcoal can cut cannabinoid content by around half, so good producers rely on careful winterisation and distillation instead.
The verdict: CO₂ leaves nothing behind and is very controllable; ethanol is efficient at scale and, once refined, gives an equally clean result. A brand that names its method but won’t show you a lab report is telling you less than one that does the opposite. See how to choose a CBD oil in the UK.
Butane, olive oil, steam and solventless extraction
- Butane and propane are used for cannabis concentrates abroad. They keep aroma well, but the gases are highly flammable and explosive under pressure, solvent can stay in the extract, and the extraction temperature changes how much plant wax carries over. For oils taken by mouth they offer little that CO₂ or ethanol can’t.
- Olive oil infusion is the traditional home method. The oil is safe, but the extract can’t be concentrated, so it stays weak and inconsistent: across 201 pharmacy-made olive oil cannabis preparations, CBD and THC levels varied by more than 50%.
- Steam distillation makes hemp essential oil, which is mostly aroma compounds. It is inefficient for cannabinoids, and the heat can damage them.
- Solventless methods separate the resin glands (trichomes) without any solvent: pressing between heated plates (rosin), shaking in ice water, or sieving dried material through a fine mesh. “Solventless” sounds cleaner, but these methods are slow and labour-intensive, so they aren’t used to make CBD oils at scale.
After extraction: winterisation, distillation and THC removal
Whichever solvent is used, the path from field to bottle is broadly the same. Full spectrum oils stop earlier; broad spectrum and isolate go further.
- Growing and drying: approved low-THC hemp is harvested, dried and ground. UK hemp licences only cover the seeds and fibre, so most CBD extract in UK products comes from hemp grown abroad. See hemp vs marijuana.
- Decarboxylation: the plant makes mostly CBDA, the raw acid form. Controlled heat converts it into CBD, before or after extraction. See what is CBGA?
- Extraction: CO₂ or ethanol dissolves the cannabinoids and terpenes, leaving a crude extract.
- Winterisation: the crude extract is mixed with ethanol and chilled hard so fats and waxes go solid. They are filtered off and the ethanol is evaporated under vacuum and recycled.
- Distillation: the oil is refined into a concentrated distillate. See what is CBD distillate?
- Chromatography (THC removal): for broad spectrum, the distillate is passed through a system that separates THC from CBD and the other cannabinoids.
- Crystallisation (isolate only): CBD is crystallised out as a white powder over 99% pure.
- Blending and testing: the extract is mixed into a carrier oil, usually MCT from coconut, to an exact strength (see MCT vs hemp seed vs olive oil), then each batch is tested by an independent lab.
How isolate and broad spectrum are made
The type of CBD you buy is decided by how far the extract is refined, not by the solvent.
| Type | Where it stops in the process | What it contains | THC |
|---|---|---|---|
| Full spectrum | After winterisation and distillation | CBD plus other cannabinoids, terpenes and plant compounds | Contains some THC |
| Broad spectrum | After chromatography removes THC | CBD plus other cannabinoids and terpenes | THC removed |
| Isolate | After crystallisation | CBD only, over 99% pure | Negligible |
Refining costs CBD. In one scaled-up university protocol (decarboxylation, CO₂ extraction, winterisation, two chromatography stages, then crystallisation), the CBD crystals were over 99% pure with negligible THC, but only 52% of the starting CBD made it through. In another study, chromatography turned 800g of full spectrum extract into 613g of broad spectrum extract containing 85% CBD and 0.02% THC.
Because full spectrum keeps THC, it is the hardest type to keep within the UK’s 1mg THC limit. See what is CBD isolate? and full spectrum vs broad spectrum vs isolate.
What to check on the label and lab report
You can’t see how an oil was extracted, but a batch lab report (certificate of analysis) shows whether it was done well. Check that:
- The batch number matches the one on your bottle, and the report is recent.
- CBD content matches the label in mg per bottle.
- THC and other controlled cannabinoids are not detected, or well under 1mg per container.
- Residual solvents (ethanol, butane and so on) are tested and pass. This is where poor extraction shows up.
- Pesticides and heavy metals are tested, especially on full spectrum oils.
- The lab is ISO/IEC 17025 accredited and independent of the brand.
See how to read CBD lab reports for a worked example, and does CBD show up on a drug test? if THC is your worry.
Can you extract CBD at home in the UK?
No, not legally. CBD comes from the flowers and leaves of the cannabis plant, including hemp, and in the UK those parts are controlled. Extracting oil from them without a Home Office licence is illegal whatever the THC content, and an oil that contains THC is itself a controlled drug. Home solvent extraction is also dangerous.
- Hemp is still cannabis in law. The Misuse of Drugs Act 1971 covers the whole plant except the mature stalk, fibre and seeds. Industrial hemp licences only cover those parts, from approved varieties with no more than 0.2% THC.
- There is no licence route for home CBD. The Home Office won’t consider applications to grow hemp to make CBD oils from the flowers or leaves, whatever the variety. Buying hemp flower to extract doesn’t get round it.
- Never use butane or other solvents at home. One US burn centre treated 101 people injured making butane hash oil over seven years: on average around a quarter of their skin was burned, and three died.
- Home oils are unreliable anyway. Even pharmacy-made olive oil preparations vary hugely in strength, so you would have no idea how much CBD or THC you were taking.
Hemp seed oil from the supermarket is a different product: it is cold-pressed from the seeds and is not a CBD extract. See hemp oil vs CBD oil and is CBD legal in the UK?
UK rules for CBD extracts
- CBD extracts are novel foods. The FSA confirmed in January 2019 that CBD extracts, isolates and the products they go into need authorisation. Hemp seed oil does not, because it has a long history of being eaten.
- The extraction method is part of the authorisation. An authorisation only covers that ingredient made with the same detailed production methods, so a brand can’t switch to a cheaper extract and rely on someone else’s approval. See the FSA’s first CBD approvals explained.
- The public list. While applications are assessed, the FSA keeps a public list of CBD food products linked to a credible application, and advises that products not on it should be removed from sale.
- The 1mg THC rule. The Home Office says it is nearly impossible to isolate CBD completely, so products often carry traces of THC. A product is only exempt if, among other conditions, no single container holds more than 1mg of THC or any other controlled cannabinoid, shown by a lab accredited to ISO/IEC 17025.
How our broad spectrum CBD is tested
All Evopure CBD products use broad spectrum CBD: the hemp extract has been refined to remove THC, so our oils, capsules and balm contain 0% THC while keeping other hemp compounds. Our Broad Spectrum CBD Oil is simply CBD in MCT oil, in 500mg, 1,000mg and 2,000mg strengths. Flow (with ashwagandha and maca) and Sleep (with passion flower) add plant extracts, and the Evolabs oils are broad spectrum too.
Every product is made in the UK and third-party tested at ISO 17025 accredited labs, and you can request the batch report for any product and strength on our lab testing page. Our CBD products are on the FSA public list, linked to validated novel food applications RP438, RP821 and RP47. Not sure how strong to go? See CBD oil strength explained.
Video: how is CBD extracted?
A short explainer on the main ways CBD is extracted from hemp.
Muslim customers often ask about ethanol in extraction: see is CBD oil halal? for how scholars view alcohol and THC.
FAQs
How is CBD extracted?
Usually with supercritical CO2 or food-grade ethanol, which dissolve cannabinoids from dried hemp flowers and leaves. The solvent is removed, the extract is winterised and distilled, THC is removed if needed, and it is blended into a carrier oil.
Is CO2 or ethanol extraction better for CBD?
Neither is automatically better. CO2 leaves no solvent residue and is very controllable; well-run ethanol extraction is just as clean once refined. The batch lab report, including residual solvents, matters more than the method.
What is winterisation in CBD extraction?
Winterisation removes plant fats and waxes from the crude extract. It is dissolved in ethanol and chilled until the waxes go solid, then filtered, and the ethanol is evaporated off.
How is THC removed from CBD oil?
After extraction and distillation, the oil is passed through chromatography, which separates THC from CBD and the other cannabinoids. The result is broad spectrum CBD, which is then tested to confirm THC is below the legal threshold.
How is CBD isolate made?
Hemp is decarboxylated, extracted, winterised and purified by chromatography, then CBD is crystallised out as a white powder over 99% pure. Each step loses some CBD: one scaled-up process kept 52% of the starting CBD.
What is solventless CBD extraction?
Methods such as rosin pressing, ice water and dry sieving separate the resin glands without any solvent. They are slow and labour-intensive, so they are used for small-batch concentrates rather than CBD oils.
Can I extract CBD at home in the UK?
No. Cannabis flowers and leaves, including hemp, are controlled in the UK, and extracting oil from them without a Home Office licence is illegal, even with olive oil. Home solvent extraction is also a serious fire risk.
Is it legal to grow hemp for CBD in the UK?
No. UK industrial hemp licences only allow the seeds and fibre to be used, and the Home Office won’t license growing hemp to make CBD oil from the flowers or leaves. That is why most CBD extract in UK products comes from hemp grown abroad.
Sources
- Home Office. Low THC cannabis (industrial hemp) licensing factsheet.
- Home Office. Drug licensing factsheet: cannabis, CBD and other cannabinoids.
- Food Standards Agency. Cannabidiol (CBD) guidance for businesses.
- Food Standards Agency. CBD products linked to novel food applications (public list).
- Lazarjani MP et al. Processing and extraction methods of medicinal cannabis: a narrative review. J Cannabis Res, 2021.
- Qamar S et al. Extraction of medicinal cannabinoids through supercritical carbon dioxide technologies: a review. J Chromatogr B, 2021.
- Calmanti R et al. From hemp to CBD crystals: a scaled-up procedure for the selective extraction, isolation, and purification of cannabidiol. ACS Agric Sci Technol, 2025.
- Gallo-Molina AC et al. Tetrahydrocannabinol separation from cannabis extracts using centrifugal partition chromatography. J Chromatogr A, 2025.
- Wang M et al. Decarboxylation study of acidic cannabinoids. Cannabis Cannabinoid Res, 2016.
- Sosa ME et al. Temperature control minimizes wax-derived alkane carryover in hydrocarbon cannabis extraction. ACS Omega, 2026.
- Carcieri C et al. Cannabinoids concentration variability in cannabis olive oil galenic preparations. J Pharm Pharmacol, 2018.
- Romanowski KS et al. Butane hash oil burns: a 7-year perspective on a growing problem. J Burn Care Res, 2017.
This guide is general information, not legal advice.
