CBD crumble: texture, purge and 4 certificate lines

A concentrate keeps a flower's cannabinoids and terpenes and leaves the plant matter behind. Most products sold as wax, shatter, budder or crumble are butane extracts, known as BHO ("butane hash oil"). According to a review published in 2018 in Substance Abuse and Rehabilitation, these names describe the product's consistency; the method behind them is the same.

The same review files crumble under waxes. These lack a full crystalline structure because they were deliberately agitated, or disturbed in some way, during extraction. The review separates "sugar crumbles", whose crystallised surface falls apart at a touch, from "wax crumbles", which crumble too but keep a smooth surface. Shatter, for its part, is glassy and brittle.

So "CBD crumble" means a hemp extract finished to this texture, with a final product that stays within the French THC limit. The whole family is described in our guide to CBD wax.

Production has two stages. First a solvent, usually butane, dissolves the compounds held in the trichomes and runs through a filter that retains the plant matter. Then comes the purge, which separates the butane from the extract with heat or under vacuum; the 2018 review mentions hot plates, vacuum ovens and shakers at this stage. Temperature, humidity and handling set the final consistency. The review puts the missing crystalline structure of waxes, crumble included, down to agitation, while shatter keeps its own.

We give no procedure here, because of the purge itself: butane evaporates at this stage and can accumulate in a closed space. Between 2008 and 2014, a burn centre in Colorado recorded 29 hospital admissions for burns linked to BHO production, with a median stay of 10 days. The stage belongs in laboratories fitted with closed-loop systems.

Rosin is made with heat and pressure. Without a solvent there is nothing to purge, and on a certificate that is the difference between rosin and crumble.

These products start from a similar composition. The finish gives the texture, and the process determines what the certificate has to prove. Our article on rosin, wax and crumble covers how to store them.

Nothing on a pouch shows this. A solvent extracts CBD and THC together without sorting them, so if both are recovered in the same proportion, the extract keeps the flower's THC/CBD ratio.

Take fictional figures. A flower shows 10% CBD and 0.20% THC, which complies. Turned into a concentrate at 60% CBD, it has been concentrated by a factor of 6, and THC follows: 0.20 × 6 = 1.2%, four times the 0.30% limit. An extract at 60% CBD stays at 0.30% THC only if the flower held 0.05% THC for 10% CBD, or if the THC is removed after extraction.

Real analyses show how far a concentrate can climb above its flower. In California, 57 concentrates from the medical market analysed in 2015 reached maximum THC levels of 23.7 to 75.9%, with one exception. Those were THC products from the medical market, but the order of magnitude of concentration applies to hemp extracts as well.

A certificate records a dated measurement of a sample from one batch. Every section is covered in our guide to reading a certificate of analysis. On a crumble, four lines count more than the others.

1. Residual solvents. Only solvent extracts carry this line. The 2015 Californian study found residual solvents or pesticides in more than 80% of the 57 concentrates tested. No French or European text sets a solvent limit specific to hemp extracts, so the benchmark available is pharmaceutical. The ICH Q3C guideline accepts 5,000 ppm for its class 3 solvents, ethanol among them, and 290 ppm for hexane; it does not list butane or propane. A readable certificate names each solvent tested, with its limit of quantification and the result.

1. Δ⁹-THC and THCA. Total THC is usually calculated as Δ⁹-THC + 0.877 × THCA. A gentle purge may leave part of the THCA undecarboxylated, so both lines must appear. The 0.30% limit applies to the finished product.

1. Other cannabinoids, tested and banned. CBD, CBDA, CBG and CBN make up the profile. The list should also state whether the laboratory looked for HHC, H4CBD or THCP, which France classified as narcotics in 2023 and 2024. What these documents show is compared in our article on concentrates and their certificates.

1. Batch, laboratory and date. A certificate whose batch number differs from the one on the pack is tied to nothing. The laboratory must be named, along with its accreditation for the test in question. The points to check are set out on our page on what a reference profile does and does not prove.

The order of 30 December 2021 caps the Δ⁹-THC content of authorised varieties at 0.30% and applies the same limit to "hemp extracts, and the products that contain them". When the Conseil d'État struck down the ban on selling raw flowers and leaves on 29 December 2022, it left that limit in place. A crumble comes under the extracts regime, with 0.30% measured on the finished product. Our article on the 0.3% limit explains how to read it.

MILDECA, the French interministerial mission against drugs, sets two further limits. CBD products may not make therapeutic claims, on pain of criminal sanctions, and CBD foods sold in France lack the required "novel food" authorisation. A crumble can therefore be sold neither as a food nor as a medicine. How it is used, and under what rules, is covered in our guide to CBD dabbing.

Phytogrammes sells no crumble, wax or shatter. The CBD resins and hash category holds only resins separated mechanically: ice water for ice-o-lator and frozen resins, dry sieving for dry sift and static. None involves a solvent. Why a sieved resin has no solvent line to show is explained in our article on solvents in hash.