CBD concentrates: what their certificates really show

A comparison of shops only means something if the documents compared can be opened by the reader. Four pages were opened on 16 September 2026. One rosin collection advertised "a third-party certificate of analysis" per product, with no batch number and no downloadable document. A second rosin page advertised 37 to 48 % cannabinoids, with no batch and no viewable certificate. A third site kept its certificates behind a trade area gated by a SIRET company number. On the product page of a resin in our own catalogue, the batch and the measured values appeared on the page.

This survey says nothing about the quality of the products: a certificate handed over on request is still a certificate, and the practice is common across the sector. It says only that a public comparison could not be built on it. The grid that follows therefore covers the processes, which decide what a certificate has to contain.

Leafly defines rosin as a heat-and-pressure process, with no chemicals, applied to flower, dry sift or water hash; live rosin starts from fresh material. The same source defines live resin as a solvent concentrate obtained from plants frozen straight after harvest. Wikipedia, under "Hash oil", lists the solvents used, among them butane, methanol, ethanol and isopropanol, notes that they are flammable and have caused explosions and serious injuries, and places the yields: 0.3 to 8 % for rosin against 10 to 20 % for a hydrocarbon extract.

Our guides cover two of these families in detail: CBD wax for solvent extracts, CBD rosin for the mechanical route. Crumble and 99 % isolate each have their own page.

Four entries are common to all of them: the batch number, which must match the one printed on the packaging, the name of the laboratory and its accreditation, the date of analysis, and the cannabinoid profile quantified by high-performance liquid chromatography. ISO/IEC 17025, 2017 version, sets the general requirements for the competence of testing and calibration laboratories; in France, accreditation is handled by Cofrac, whose stated mission is to satisfy itself as to the competence and impartiality of conformity assessment bodies.

The fifth entry depends on the process. Rosin, dry sift and ice-o-lator involve nothing but heat, pressure, iced water or sieves: there is no solvent to look for. An extract made with butane, propane or ethanol has to publish a residual-solvent line naming each compound sought, its limit of quantification and the numerical result. A blanket "compliant" statement, with no list and no value, allows no checking at all.

For an isolate, the advertised purity is added, and it reads as a measured percentage. The full melt grade, often quoted on premium hash, belongs to another register: it is an extractor's verdict on behaviour under heat, and no laboratory issues it.

This is the most frequent gap, and it singles out no family in particular. On the rosin page consulted on 16 September 2026, the advertised range ran from 37 to 48 %, with no batch attached. In our catalogue of CBD resins and hash, the Rosift CBG/CBD page publishes values measured by HPLC for batch PG-26-3A2B: 20.2 % CBG, 4.6 % CBD, 0.5 % CBC, 0.4 % CBN and 0.2 % Δ⁹-THC, with price tiers from 5.45 €/g for 2 g down to 1.43 €/g for 100 g.

The two figures do not describe the same thing. A range covers a line-up and commits to no sample; a measured value applies to a dated batch. The useful question is therefore not "what percentage?" but "which batch, which laboratory, which date?". Our our laboratory page describes the journey of a sample, from receipt of the batch to publication of the results.

There is no French or European limit specific to residual solvents in hemp extracts. Commission Regulation (EU) 2023/915 sets maximum levels for contaminants in food, including 3.0 mg/kg expressed as THC equivalents for hemp seeds and 7.5 mg/kg for seed oil, but it does not cover extraction solvents.

The framework available is a pharmaceutical one. The ICH Q3C guideline, taken up by the European Pharmacopoeia and by USP chapter 467, sorts solvents into three classes: class 1, to be avoided, known or suspected carcinogens; class 2, to be limited; class 3, low toxic potential. The class 1 limits are tight: 2 ppm for benzene, 4 ppm for carbon tetrachloride, 5 ppm for 1,2-dichloroethane, 8 ppm for 1,1-dichloroethene, 1500 ppm for 1,1,1-trichloroethane. In class 2, hexane is limited to 290 ppm and methanol to 3000 ppm. Class 3, which groups ethanol, acetone, heptane, pentane and 2-propanol, is allowed up to 50 mg per day, that is 5000 ppm or 0.5 %. Butane and propane, the solvents most widely used for concentrates, appear in none of these tables.

Other jurisdictions have filled that gap. Californian rules set 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 values do not apply in France, but they give an order of magnitude for reading a foreign certificate.

Whatever the family, the finished product must contain no more than 0.30 % Δ⁹-THC. 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 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 two boundaries: no claim of a health benefit, under threat of criminal penalties, and CBD foodstuffs placed on the market without the authorisation required.

A word on where we sit in this grid. Phytogrammes sells no product obtained by solvent extraction: no wax, no crumble, no shatter, no live resin, no isolate. The 15 references in the category come from mechanical separation, with iced water or dry. None of them has a residual-solvent line to produce, which exempts it from none of the other entries. This guide is there to read a certificate, including that of a concentrate bought elsewhere.

• Phytogrammes, CBD resin and hash category (15 references)
• Phytogrammes, Rosift CBG/CBD page, batch PG-26-3A2B (HPLC values, price tiers)
• Phytogrammes, our laboratory (the journey of a sample)
• Leafly, glossary "Rosin" (heat and pressure, no solvent)
• Leafly, glossary "Live resin" (frozen plant, solvent)
• Wikipedia (en), "Hash oil" (solvents, textures, yields 0.3 to 8 %)
• ICH Q3C (R8), residual solvents (classes 1 to 3, limit tables)
• EMA, ICH Q3C (R9) residual solvents, applicable from 29 April 2024
• California, 4 CCR § 15718, residual solvent action levels
• Wikipedia (fr), "ISO/CEI 17025" (2017 version, Cofrac accreditation)
• Cofrac, accreditation mission
• Gardenz, reading a CBD laboratory analysis
• Légifrance, arrêté du 30 décembre 2021 (article 1, I and III)
• Conseil d'État, decision of 29 December 2022, no. 444887
• MILDECA, "Le CBD" (claims of a health benefit, foodstuffs)