Cannabis extraction & concentrates — knowledge hub

Concentrates isolate cannabinoids and terpenes from the plant matrix — from solventless rosin presses to industrial CO2 systems. This hub covers processes, purity standards, safety risks (especially butane explosions) and the Swiss legal framework for THC and CBD extracts.

What extraction actually does — and where the differences lie

Extraction separates the active components of the cannabis plant — cannabinoids, terpenes, and in some cases flavonoids — from the plant material. All methods essentially do the same thing, but differ in three dimensions that determine the final price and the experience: selectivity (how cleanly they separate), terpene preservation (how much aroma survives), and residue risk (what solvent remains behind).

Solvent-free methods such as rosin work using only pressure and heat. They are residue-free by definition and preserve terpenes very well, but have lower yields and are therefore more expensive per gram of active ingredient. Hydrocarbon extraction (BHO, PHO) delivers high yields and excellent terpene profiles, but requires a closed-loop system and thorough post-processing, as residual solvents would otherwise remain in the final product. CO₂ extraction scales well industrially and is low in residues, but loses volatile terpenes, which are often added back later. Ethanol is inexpensive and robust, but extracts chlorophyll and waxes along with the cannabinoids and requires winterisation.

For consumers, the practical consequence is simple: the certificate of analysis is what matters. A reputable COA not only lists cannabinoids, but also residual solvents for solvent-based products, as well as pesticides and heavy metals.

  • Rosin: solvent-free, very good terpene preservation, low yield, highest price per gram of active ingredient
  • BHO/PHO: high yield and aroma fidelity, residual solvent analysis mandatory
  • CO₂: scalable and low-residue, terpenes are partially lost
  • Ethanol: inexpensive and robust, winterisation required, risk of chlorophyll taste

Legal framework for extracts in Switzerland

Legally, extracts are not a special case — the same threshold applies as for flowers. The decisive factor is the total THC content of the finished extract, not that of the starting material. And this is precisely where the industry's most common legal violation occurs: during extraction, cannabinoids are concentrated. When concentrated by a factor of ten, legal starting material with 0.8% total THC becomes an extract with 8% — and thus a narcotic. The decisive factor is always the total THC, i.e. THC plus THCA multiplied by the factor 0.877. A product with 0.4% delta-9-THC and 0.9% THCA has around 1.19% total THC and is therefore a narcotic — even if the packaging says «under 1%».

Home extraction is also a safety issue. Open butane extraction indoors poses a real danger to life due to the risk of explosion from gases heavier than air, and has already led to serious accidents in Switzerland. Anyone extracting themselves should switch to solvent-free methods — rosin with a press is possible without any fire risk.

In case of suspected poisoning or accident, Tox Info Suisse can be reached around the clock on 145.

Guide through this cluster

The subpages go through each method individually — from rosin and Ice-o-lator to BHO and CO₂ to ethanol and distillation — and answer the same questions in each case: how does it work, what yield is realistic, which residues need to be checked, and how can you tell from the end product whether the work was done cleanly.

Anyone who just wants to know which product suits them starts with the method comparisons; those who produce themselves will find the technical parameters, including temperature and pressure ranges, on the individual pages.

Analytical standards and contaminant testing in Swiss laboratories

The quality of cannabis extracts can hardly be reliably assessed visually. Swiss laboratories use high-resolution analytical methods such as liquid chromatography to determine the exact spectrum of cannabinoids and terpenes. Since extracts highly concentrate the starting material, the risk of residues also multiplies. Pesticides, heavy metals, or mold spores that were barely detectable on the flowers can exceed critical limit values in the concentrate. Professional providers must therefore have every batch comprehensively tested to guarantee the safety of their products.

In addition to biological contaminants, chemical solvent residues are a key focus of quality control. While solvent-free processes such as rosin pressing bypass this risk, methods using ethanol or butane require thorough purging. Swiss laboratories test these extracts for volatile organic compounds that remain in the end product if evaporation is incomplete. Consumers should only purchase products whose certificates of analysis are directly accessible and which have been certified by accredited Swiss testing bodies. This protects against harmful vapors during subsequent heating.

  • Detection of heavy metals and pesticides by accredited laboratories
  • Determination of the exact total THC content to comply with statutory limits
  • Exclusion of hazardous solvent residues in the final product
  • Transparency through batch-specific certificates of analysis for end consumers

Medical extracts in the Swiss healthcare system

Since the legislative amendment in August 2022, access to medical cannabis extracts in Switzerland has been significantly simplified. Doctors can prescribe these preparations directly and without an exceptional licence from the Federal Office of Public Health (BAG). These extracts are subject to strict pharmaceutical standards and are prepared as magistral formulations in specialised pharmacies or dispensed as finished medicinal products. Standardisation guarantees that each dose contains exactly the same amount of active ingredients, which is essential for reliable therapy.

In contrast, there are the time-limited pilot trials in various Swiss cities such as Basel or Zurich. These scientific studies investigate the regulated sale of cannabis for recreational purposes, where standardised extracts and concentrates may also be used. While medical extracts are distributed via Swissmedic-regulated channels, the products in the pilot trials comply with the specifications of the BAG in accordance with Article 8b of the Narcotics Act (BetmG). Both systems demonstrate how controlled distribution channels increase consumer safety compared to the illegal market.

  • Direct medical prescription without a BAG exceptional licence since August 2022
  • Preparation under strict pharmaceutical guidelines in Swiss pharmacies
  • Dispensing of standardised concentrates within the framework of scientific pilot trials
  • Strict separation between medical use and regulated recreational consumption

Post-processing: The importance of winterisation and filtration

The actual extraction is often only the first step on the way to a pure concentrate. In addition to the desired active ingredients, crude oils contain significant amounts of plant waxes, lipids, and chlorophyll. These accompanying substances are undesirable during vaporisation, as they impair the taste and can irritate the respiratory tract when inhaled. Through processes such as winterisation, in which the extract is dissolved in alcohol and cooled down significantly, these fats precipitate and can then be filtered out. The result is a significantly purer and more stable end product.

The precision of this post-processing is crucial for the quality of the end product. If filtration is incomplete, the concentrate tends to become cloudy during storage and quickly loses its aroma. In addition, remaining plant fats burn at the high temperatures of vaporisation, leading to a harsh sensation when inhaled. High-quality extracts are therefore characterised by a clear, often amber-coloured consistency. This visual purity is a direct indication of professional purification and protects the health of the users.

  • Removal of undesirable plant waxes and lipids through targeted cooling
  • Improvement of inhalation quality and protection of the respiratory tract during vaporisation
  • Extending the shelf life and stability of the concentrate through filtration
  • Prevention of bitter taste through the removal of chlorophyll

Risk minimization and safe storage of concentrates

Handling highly concentrated cannabis products requires particular caution, as the density of active ingredients is many times higher than in conventional flowers. Inadvertent dosing can quickly lead to undesirable side effects. To minimize risks, consumers should always start with the smallest amounts and wait for the effects. Should an overdose or health problems nevertheless occur, Tox Info Suisse provides rapid and expert assistance for those affected and their relatives in Switzerland 24/7 via the emergency number 145.

Storage also plays an essential role in safety and preserving product quality. Extracts are sensitive to light, heat, and oxygen, which leads to a rapid degradation of cannabinoids. An improperly stored product not only loses its potency but can also form harmful degradation products through oxidation processes. Storage in airtight glass containers in a cool, dark place is ideal. This protects the sensitive terpenes and prevents the concentrate from absorbing moisture and molding.

  • Cautious dosing due to the extremely high concentration of active ingredients
  • Rapid assistance in case of suspected poisoning via the emergency number 145 of Tox Info Suisse
  • Storage in airtight glass containers to protect against light and oxygen
  • Prevention of quality loss and harmful oxidation products through cooling

FAQ

Is self-made rosin legal in Switzerland?

Only if the final product remains below 1 % total THC. Since rosin concentrates cannabinoids many times over, an extract made from legal CBD material almost always exceeds this threshold for the THC content in practice. Legally, this therefore creates a narcotic, even if the starting material was freely available for sale.

How do I recognize a cleanly produced extract?

By the certificate of analysis with a matching batch number, which, in addition to the cannabinoid profile, also shows residual solvents, pesticides, and heavy metals. Sensorially, a clear terpene aroma without chemical or burnt notes, a uniform consistency, and a light to amber color indicate clean work. Dark, pungent-smelling extracts point to plant material content or overheating.

Which method preserves terpenes best?

Cold, solvent-free methods and live variants in which freshly frozen material is processed — i.e., live rosin and live resin. They manage without the drying step, in which a large part of the volatile terpenes is lost. CO₂ and ethanol extracts are often obtained with low terpene content and subsequently flavored.

Why is butane extraction at home so dangerous?

Butane is heavier than air and accumulates on the floor of closed rooms, where any spark — light switches, refrigerators, static electricity — can lead to a deflagration. Professional systems therefore operate closed, with extraction and explosion protection. For home use, the press is the only responsible alternative.

What is the limit for THC in Swiss road traffic after consuming extracts?

A strict zero-tolerance policy applies to Swiss road traffic, with a statutory THC detection limit of 1.5 micrograms per liter of blood. Anyone exceeding this limit is legally deemed unfit to drive, which results in the revocation of their driver's license and criminal consequences. Since extracts are highly concentrated, the active ingredient often remains detectable in the body for significantly longer than after consuming conventional flowers. Consumers should be aware that fitness to drive is compromised for an extended period after consuming concentrates.

Am I allowed to produce medical cannabis extract myself from my prescribed flowers?

No, the independent production of extracts from medical flowers is not legally permitted in Switzerland. Medical cannabis extracts must be produced under strictly controlled conditions in pharmacies or by licensed manufacturers to ensure patient safety. In the case of self-production, there is also a risk that the statutory limit for total THC will be exceeded in an uncontrolled manner, which would legally classify the product as an illegal narcotic. Patients must therefore rely on finished, standardized preparations from the pharmacy.

What role do the cantonal authorities play in enforcing the regulations for cannabis extracts?

In Switzerland, the cantonal authorities are responsible for the concrete enforcement of the Narcotics Act and the execution of controls. In practice, this leads to regional differences in how controls are handled and fines are enforced. While the possession of up to 10 grams of THC cannabis by adults can be punished nationwide with a fixed penalty of 100 francs, the intensity of controls varies depending on the canton. The monitoring of points of sale for CBD extracts is also the responsibility of the respective cantonal laboratories.

Why is the total THC level more decisive for legality in extracts than in flowers?

The total THC level is so decisive for extracts because the extraction process highly concentrates the cannabinoids of the raw material. Even if the flowers used were legal and below the limit of 1%, the finished concentrate almost always exceeds this value due to the concentration process. Swiss legislation calculates total THC using the formula THC plus THCA multiplied by 0.877. If this value in the finished extract is 1% or higher, the product automatically falls under the Narcotics Act and is illegal.