To extract CBD oil from hemp, producers dry and mill the flowers, dissolve the resin with a solvent such as supercritical CO₂ or ethanol, remove the solvent and dilute the extract in a carrier oil. The method and its temperature and pressure settings decide which cannabinoids and terpenes end up in the extract. Formula Swiss uses CO₂ extraction only, with no alcohol.
Key facts
- Raw material
- Dried hemp flowers (inflorescences), where the resin glands are concentrated
- Main extraction methods
- Supercritical CO₂, ethanol and hydrocarbons such as butane; solvent-free mechanical methods also exist
- When CO₂ becomes supercritical
- Above about 31 °C (304.1 K) and 73.8 bar
- Key chemical step
- Heat converts the plant's acids (CBDA, THCA) into CBD and THC: decarboxylation
- Best method (as of October 2026)
- None suits every purpose; reviews say the choice depends on the target profile
- At Formula Swiss
- CO₂ extraction only; oils formulated, bottled and labelled in Küssnacht am Rigi; every batch tested in Switzerland
How is CBD extracted from hemp, step by step?
- Harvest and drying: the flowers are harvested and dried. Careful drying limits mould: in a large study of cannabis flowers, drying to 12 to 14% moisture was linked with lower mould and yeast counts (Punja 2023).
- Milling: the dried material is ground so the solvent can reach the resin.
- Extraction: a solvent dissolves cannabinoids, terpenes and other resin compounds out of the plant material.
- Solvent removal and refining: the solvent is separated from the extract. With CO₂ this happens by releasing the pressure; ethanol and butane have to be evaporated off.
- Decarboxylation: heat converts acidic cannabinoids such as CBDA into CBD (see below).
- Formulation: the extract is diluted in a carrier oil, such as MCT, olive or hemp seed oil, to the strength printed on the label.
- Testing: each batch is analysed to confirm its cannabinoid content, including THC. Read how to read a certificate of analysis.
What is CO₂ extraction?
Carbon dioxide becomes "supercritical" above about 31 °C and 73.8 bar (NIST). In that state it flows like a gas but dissolves compounds like a liquid. Small changes in pressure and temperature change which compounds it picks up, so the process can be tuned towards cannabinoids or terpenes (de Aguiar 2023).
When the pressure is released, the CO₂ turns back into a gas and leaves the extract, so there is no extraction solvent to evaporate off afterwards. Supercritical CO₂ extraction of the flowers is also used to make cannabis-based medicines (Grof 2018). The drawback is cost: the method needs specialised high-pressure equipment.
CO₂ vs ethanol vs butane: which extraction method is best?
A 2026 review of the extraction literature concluded that there is no universal method. The right choice depends on the goal, for example keeping acidic cannabinoids, keeping terpenes or reducing chlorophyll. Solvent, temperature, time and pressure all shape the result (Lima 2026).
| Method | How the solvent is removed | Strengths | Drawbacks |
|---|---|---|---|
| Supercritical CO₂ | Pressure release; CO₂ returns to gas | Selective and tunable; no solvent left to evaporate | Expensive high-pressure equipment |
| Ethanol | Evaporation | Simple and widely available; extracts a broad range of compounds | Flammable; can also pull out chlorophyll and other unwanted compounds |
| Butane and other hydrocarbons | Evaporation | Extracts resin efficiently | Highly flammable; solvent must be removed completely |
Higher temperatures during processing can convert acidic cannabinoids and cause terpenes to be lost, which changes both the chemistry and the smell of the extract (Lima 2026).
Why is hemp extract heated?
Living hemp makes very little CBD directly. It makes cannabidiolic acid (CBDA), and THCA instead of THC. These acids are the main cannabinoids in the plant, and heat removes a carboxyl group to turn them into CBD and THC. This step is called decarboxylation. In tests at 80 to 145 °C, THCA converted twice as fast as CBDA (Wang 2016). More on the acid form in what is CBDA?
Can you extract CBD oil from hemp at home?
Home extraction has real risks. Ethanol and butane are flammable, and without a lab test you can't know how much CBD, or THC, the result contains. Extraction concentrates all the cannabinoids in the plant, THC included. Growing and processing hemp is also regulated in most countries. If you want a measured product, buy one with a batch certificate.
How is CBD oil tested after extraction?
A lab measures the cannabinoids in each batch, usually by chromatography, to check that the CBD content matches the label and that THC stays within the legal limit. Tests can also look for residues such as solvents or pesticides. See how hemp is tested for THC and our quality control page.
What is the difference between CBD oil and hemp seed oil?
CBD oil is made from an extract of the flowers, diluted in a carrier oil. Hemp seed oil is pressed from the seeds. Its cannabinoid content is low and varies by product: an analysis of ten commercial hemp seed oils found significant differences between them (Citti 2019). Read hemp oil vs CBD oil. For CBG, see how CBG oil is made.
From our production
Our oils are formulated, bottled and labelled in Küssnacht am Rigi. We test every batch in Switzerland, and we have never had a failed test since 2013.
— Robin Roy Krigslund-Hansen, co-founder and CEO
Frequently asked questions
How do you extract CBD oil from hemp?
The dried flowers are milled and extracted with a solvent, usually supercritical CO₂ or ethanol. The solvent is removed, the extract is heated to convert CBDA into CBD, and it is then diluted in a carrier oil and tested.
What is CO₂ extraction?
It uses carbon dioxide above about 31 °C and 73.8 bar, where it dissolves compounds like a liquid. Adjusting pressure and temperature tunes what it extracts, and the CO₂ turns back into a gas when the pressure is released.
Is CO₂ extraction better than ethanol extraction?
Neither is best for every purpose. CO₂ is selective and leaves no solvent to evaporate but needs expensive equipment. Ethanol is simpler but flammable and can also extract unwanted compounds such as chlorophyll.
Why is hemp extract heated?
The plant mainly contains acidic cannabinoids such as CBDA. Heat removes a carboxyl group and converts them into CBD and THC, a step called decarboxylation.
Does Formula Swiss use CO₂ extraction?
Yes. Formula Swiss uses CO₂ extraction only, with no alcohol. The oils are formulated, bottled and labelled in Küssnacht am Rigi, and every batch is tested in Switzerland.
Related guides
This article is general information about how CBD is made. It is not a guide to home extraction. Formula Swiss CBD oils are cosmetics for use on the skin; they are not food supplements or medicines. Read our full disclaimer.
Last reviewed:
Sources
- Lima SNA et al. From plant to extract: different factors in the extraction of Cannabis sativa L. inflorescences. Cannabis Cannabinoid Res 2026 (online ahead of print). doi:10.1177/25785125261454834
- de Aguiar AC et al. Supercritical carbon dioxide technology for recovering valuable phytochemicals from Cannabis sativa L. Molecules 2023;28(9):3849. doi:10.3390/molecules28093849
- Grof CPL. Cannabis, from plant to pill. Br J Clin Pharmacol 2018;84(11):2463–2467. doi:10.1111/bcp.13618
- National Institute of Standards and Technology. Carbon dioxide: phase change data (critical temperature and pressure). NIST Chemistry WebBook, SRD 69
- Wang M et al. Decarboxylation study of acidic cannabinoids: a novel approach using ultra-high-performance supercritical fluid chromatography/photodiode array-mass spectrometry. Cannabis Cannabinoid Res 2016;1(1):262–271. doi:10.1089/can.2016.0020
- Punja ZK et al. Total yeast and mold levels in high THC-containing cannabis inflorescences are influenced by genotype, environment, and pre- and post-harvest handling practices. Front Microbiol 2023;14:1192035. doi:10.3389/fmicb.2023.1192035
- Citti C et al. Cannabinoid profiling of hemp seed oil by liquid chromatography coupled to high-resolution mass spectrometry. Front Plant Sci 2019;10:120. doi:10.3389/fpls.2019.00120
