Can a CBD hash contain solvents? Reading the COA

The first three rows describe a physical separation: plant material is set aside from the trichome heads without anything ever being dissolved. The Leafly glossary describes rosin in those terms, obtained through heat and pressure, with no chemicals, from flower, dry sift or water hash. Our guide to CBD rosin covers that route in detail.

The last two describe a dissolution. Wikipedia, under "Hash oil", lists the solvents used in the sector, among them butane, methanol, ethanol and isopropanol, and notes that they are flammable and have caused explosions, serious injuries and deaths. Our guides to CBD wax and crumble describe this family and the vacuum purge that follows extraction. The answer to the question in the title therefore comes down to one piece of information: which process produced the batch.

A residual solvent is what remains of the extraction solvent in the finished product after the purge. You cannot see it, and you cannot reliably smell it: you measure it.

The reference method is gas chromatography with headspace injection. The principle is straightforward: the sample is sealed in a vial and heated, which drives the volatile compounds into the gas phase above the sample; that gas is then drawn off and injected. Separation follows on a column, and quantification comes from a flame ionisation detector or from mass spectrometry. Mass detection has the advantage of formally identifying every peak, which avoids confusing two compounds sharing a retention time.

The list of compounds sought follows the processes found on the market: ethanol, butane and propane first of all, then acetone, hexane, benzene and the sector's other solvents. One analytical point matters as much as the result: the limit of quantification. A "not detected" result means nothing without it, since it only says "below the threshold this method can measure". A readable certificate therefore publishes, for each solvent, the value found and that limit.

There is no French or European residual-solvent limit specific to hemp extracts. Commission Regulation (EU) 2023/915 sets maximum levels for contaminants in food: 3.0 mg/kg expressed as THC equivalents for hemp seeds, 7.5 mg/kg for hemp seed oil, with a proportionality rule for derived products. It does not cover extraction solvents, and a hash is not a foodstuff in any case.

The available reference point is a pharmaceutical one. The ICH Q3C guideline, transposed into the European Pharmacopoeia and into USP chapter 467, sorts solvents into three classes: class 1, to be avoided, known or strongly suspected carcinogens and environmental hazards; class 2, to be limited; class 3, low toxic potential. The values are numerical.

Two remarks on that table. Class 3 covers the solvents allowed up to 50 mg per day without particular justification, which corresponds to the 5000 ppm shown. And both butane and propane, the solvents most widely used for hemp concentrates, appear in none of these tables: the pharmaceutical reference does not cover them. The version in force in the Union, ICH Q3C (R9), has applied since 29 April 2024.

Other jurisdictions have set their own thresholds. Californian cannabis rules publish action levels in micrograms per gram: 1.0 for benzene in category I; 5000 for butane, propane, ethanol, acetone, isopropyl alcohol, heptane and pentane; 290 for hexane, in category II. These figures carry no weight in France, but they give the order of magnitude to expect when a foreign certificate shows a column of limits.

Four points can be checked in a few seconds.

• The batch. The number on the certificate must be the one printed on the packaging. Without that match, the document attaches to nothing.
• The list, not the statement. A useful certificate names every solvent sought. A "compliant" or "PASS" box with no list allows no checking at all.
• The limit of quantification. It accompanies every result. A "not detected" with no limit beside it is not a measurement.
• The laboratory and its scope. ISO/IEC 17025, 2017 version, sets the general requirements for the competence of testing and calibration laboratories; in France, accreditation is handled by Cofrac. An accreditation covers specific tests: the one covering cannabinoids does not necessarily cover solvents.

One particular case is worth naming: a missing section. On a rosin or a washed hash, that is normal, since no solvent is involved. On a wax or a crumble, it is missing data. Our comparison of concentrate certificates sets out what each family has to produce.

The CBD resin and hash category holds 15 references, all of them from mechanical separation: iced water for the ice-o-lator, bubble and frozen, dry sifting for the dry sift and static. No butane, no propane, no ethanol, no CO2. There is therefore no purge, no possible residual solvent, and nothing to measure on that point.

What these batches do publish is the rest of the file. On the Rosift CBG/CBD page, batch PG-26-3A2B shows values measured by high-performance liquid chromatography: 20.2 % CBG, 4.6 % CBD, 0.5 % CBC, 0.4 % CBN and 0.2 % Δ⁹-THC. The our laboratory page describes the circuit: receipt and referencing of the batch, a representative sample sent to an independent laboratory, analysis, verification against the 0.30 % threshold, issue of the certificate, publication of the results on the product page.

The legal framework does not change with the process. The arrêté du 30 décembre 2021 (French ministerial order) authorises varieties of Cannabis sativa L. listed in the official catalogues whose Δ⁹-THC content is no higher than 0.30 %, and applies the same threshold to hemp extracts and to the products that incorporate them. The Conseil d'État (France's supreme administrative court), on 29 December 2022 (no. 444887), annulled the ban on selling raw flowers and leaves to consumers, while keeping that threshold as the criterion. MILDECA (the French interministerial mission on drugs) restates that no claim of a health benefit may be made, under threat of criminal penalties. These products are for adults only and are not intended to be swallowed.

• Phytogrammes, CBD resin and hash category (15 references)
• Phytogrammes, Rosift CBG/CBD page, batch PG-26-3A2B
• Phytogrammes, our laboratory (the journey of a sample)
• Leafly, glossary "Rosin" (heat and pressure, no solvent)
• Wikipedia (en), "Hash oil" (solvents used, flammability)
• Ellutia, residual solvent analysis by gas chromatography
• Technology Networks, headspace and flame ionisation detection
• ICH Q3C (R8), residual solvents (classes and limit tables)
• EMA, ICH Q3C (R9), applicable from 29 April 2024
• California, 4 CCR § 15718, residual solvent action levels
• Regulation (EU) 2023/915, contaminants in food
• FPS Public Health (Belgium), hemp and CBD FAQ (3.0 and 7.5 mg/kg)
• Wikipedia (fr), "ISO/CEI 17025" (2017 version, Cofrac accreditation)
• Légifrance, arrêté du 30 décembre 2021 (article 1, I and III)
• Conseil d'État, decision of 29 December 2022, no. 444887
• MILDECA, "Le CBD"