CBD resin colour: white, blond, pink, what the shade says
The colour of a hemp resin is a clue, never a proof. A shade has four possible origins: the variety grown, the fineness of the fraction, ageing in air and light, and the addition of material foreign to the plant. Those four causes sometimes produce the same hue, and none of them can be read by eye. The batch certificate, on the other hand, tells them apart.
Contents
- 011. Four causes of shade, and what each one proves
- 022. The cultivar: what anthocyanins actually do
- 033. Method: why a piatella is pale
- 044. Time, air and light: why a resin darkens
- 055. Pink and blue: the shades that call for a check
- 066. What the certificate settles, and what it does not
- 07Frequently asked questions
- 08Sources
White hash, white piatella, white haschich, purple resin, sometimes pink or blue: these names travel fast, and they are made to say what they do not say. The figures quoted here come from the catalogue certificates and from published work.
> Key points > > - A very pale resin signals a fine fraction, not a high content. > - The anthocyanins of purple varieties sit in the tissues of the plant, not in the trichomes. > - A resin darkens as it ages, but cold curing darkens it too, without degradation. > - No known hemp pigment accounts for a true blue in a resin. > - Colour gives neither the content, nor the Δ⁹-THC, nor the presence of a foreign body.
1. Four causes of shade, and what each one proves
A resin gathers the trichome heads separated from the flower, then pressed or put through a curing period. Its shade adds up four contributions: the pigments of the plant, the plant matter left in the fraction, the products of oxidation, and whatever may have been added afterwards.
| Cause of the shade | Visible effect | What can be concluded from it |
|---|---|---|
| Cultivar and anthocyanins | Reds to purples, in the tissues of the plant | The variety, not the purity |
| Fineness of the fraction | Cream to pale blond without plant matter, green to brown with it | Mechanical purity |
| Oxidation, light, time | Darkening from blond towards amber then brown | Age and storage |
| Added material | Any shade at all, bright colours included | Nothing: an addition is not visible |
The table reads in one direction only: a cause produces a shade, but a shade does not lead back to its cause. Useful as a question, insufficient as an answer.
2. The cultivar: what anthocyanins actually do
Purple varieties owe their hue to anthocyanins, the family of pigments that also colours red cabbage. Work published in Antioxidants in 2023 by Laura Bassolino and her co-authors identifies keracyanin, or cyanidin-3-rutinoside, as the majority anthocyanin of Cannabis sativa L., measured by HPLC-MS/MS at up to 885.58 mg per 100 g of fresh matter in purple tissues.
The first point that matters is location: those pigments were measured in the leaves, the stems and the purple flowers, and were missing from the organs that stayed green in certain genotypes. Nothing places them in the trichome heads, the fraction that separation sets out to isolate. The more thoroughly a resin is stripped of plant matter, the fewer reasons it has to be purple.
The second is independence from the cannabinoids. A study published in 2025 in the Journal of Cannabis Research varied the temperature from 0.5 to 22 °C: anthocyanin accumulation peaks around 8 and 15 °C and falls away at both ends, while the cannabidiol content rises linearly, with no correlation between the two. A purple piatella tells you about the variety, not about what the certificate will measure.
3. Method: why a piatella is pale
The word white, in white hash or white piatella hash, covers in practice a range running from cream to very pale blond, and that paleness has a simple mechanical explanation: the fraction holds very little plant matter.
The piattella entry in the lexicon describes a creamy slab, almost translucent at the edge, cold-finished under vacuum from a wash of fine fractions. The grade expected upstream is that of full melt, 73u to 90u mesh: at that degree of purity the material melts without residue, where lower grades leave a dark deposit and ash. Dry-sifted, the logic is the same: working the material too hard sends plant dust through with the resin, and the yield gained can be read in the colour.
Paleness therefore reports on mechanical purity, never on content. The Piatella is measured at 18.0 % CBD by HPLC on batch PG-26-F1E2; the Afghan, which its product page describes as a dense, dark resin, is measured at 18.5 % CBG on batch PG-26-ED80. The darker of the two carries the higher figure. The comparison of frozen, piatella, 120u and static takes up the same idea family by family, and the 15 references in the resins and hash category are presented with their measured content.
One last trap: a name that evokes a colour does not always describe one. The Caramelo 120u page states that its own name comes from its aromatic profile.
4. Time, air and light: why a resin darkens
A resin has no fixed shade. The reference work remains that of Fairbairn and his co-authors, published in 1976 in the Journal of Pharmacy and Pharmacology on samples stored for up to two years: light, even indirect, emerges there as the leading factor in cannabinoid loss, the effect of temperature up to 20 °C is judged negligible, and oxidation in air brings notable losses. The authors add that the loss of tetrahydrocannabinol under light does not raise cannabinol, whereas oxidation in darkness does raise it.
Recent work gives the scales. In Molecules in 2026, Shaikh and his co-authors followed the photolysis of isolated cannabinoids by mass spectrometry: under ultraviolet B at 280 nm, the intensity falls by half in about thirteen minutes for THC and fifteen for CBD, while nothing notable appears under ultraviolet A at 365 nm. Measured on isolated molecules, the finding explains opaque or vacuum packaging.
One nuance remains that the eye cannot settle. The Frozen Hash page describes a supple resin, paler than a pressed hash, which darkens in air: the darkening goes with ageing. But the piattella lexicon entry describes a curing period at the end of which the colour darkens slightly and the slab stops crumbling: this time, it is the expected sign of the process. What can be measured is the cannabinol line on the certificate, 0.4 % on batch PG-26-F1E2 and 0.3 % on batch PG-26-AA10.
5. Pink and blue: the shades that call for a check
A pink hue remains plausible. The cyanidin glycosides identified in hemp turn red in acid conditions, and a residue of pigmented tissue is enough to tint a fraction. A pink piatella is in no way abnormal in itself, but it proves nothing.
Blue is another matter. For a cyanidin to express a stable blue, two conditions are needed, as the work of Fenger and his co-authors, published in 2021 in the International Journal of Molecular Sciences, sets out: a neutral to slightly alkaline pH, and metal ions, aluminium or iron, that shift its absorption, by up to about 110 nm with iron at pH 5.7. A hemp resin is neither a buffered solution nor a medium loaded with metal ions. A blue piatella, in the sense of a true blue, therefore has no explanation in the pigment chemistry of the plant: the shade calls for a question about the origin of the batch before any purchase.
That caution is not theoretical. SINTES Point no. 11, published in June 2026 by Sabrina Cherki and Cindy Feng for the OFDT, records 742 collections in 2024 and 1 086 in 2025, and reports numerous adulterations with synthetic cannabinoids, most often without the knowledge of the people concerned, in products on open sale; the resin collections concerned rise from 10 in 2024 to 32 in 2025. Such additions do not necessarily change the appearance of the product. Our article on jaune mousseux returns to these street names.
6. What the certificate settles, and what it does not
A batch certificate answers what colour leaves open: cannabinoids by HPLC, terpenes by GC-MS, heavy metals by ICP-MS, pesticides by LC-MS/MS, with the date and the laboratory. The our laboratory page describes the six steps between the arrival of a batch and its going online. A search such as piatella CBC in fact bears on one line of that document, cannabichromene, measured at 0.5 % on batch PG-26-F1E2.
The accreditation cited on the product pages, ISO/IEC 17025 in its 2017 version, sets the requirements for the competence and impartiality of testing laboratories. In France, the Cofrac grants it for a defined scope.
The order of 30 December 2021 authorises only the varieties of Cannabis sativa L. listed in the official catalogues, whose Δ⁹-THC content is not higher than 0.30 %, and applies the same ceiling to hemp extracts and to the products that contain them (article 1, I and III). The Conseil d'Etat, on 29 December 2022 in decision no. 444887, annulled the ban on selling raw flowers while maintaining that threshold. These products are reserved for adults and are not foodstuffs.
Frequently asked questions
Why is a piatella white?
Because it comes from a fine fraction very low in plant matter, of full melt grade on 73u to 90u mesh, cold-finished under vacuum rather than hot-pressed. Paleness reflects that mechanical purity, never the content, which is read on the certificate.
Is a pink resin natural?
It can be. The anthocyanins of the plant, dominated by cyanidin-3-rutinoside, turn red in acid conditions, and a residue of pigmented tissue is enough to tint a fraction. But a natural pink and a pink of another origin look alike: analysis is what separates them.
Does a hash that darkens mean it has gone off?
Not necessarily. On a piattella, the cold curing period darkens the slab slightly: that is the expected sign of the process. Elsewhere, darkening goes with oxidation in air, whose measured marker is cannabinol. The shade does not distinguish the two cases; the CBN line on the certificate does.
Does colour indicate the content?
No. In the catalogue, the pale Piatella is measured at 18.0 % CBD on batch PG-26-F1E2 and the Afghan, described as dense and dark, at 18.5 % CBG on batch PG-26-ED80. Contents are measured by HPLC.
Sources
- Phytogrammes, lexicon "Piattella" (accessed 16 September 2026)
- Phytogrammes, Piatella product page, batch PG-26-F1E2
- Phytogrammes, Afghan product page, batch PG-26-ED80
- Bassolino et al., hemp anthocyanins, Antioxidants, 2023
- Kim et al., anthocyanins and cannabidiol, J. Cannabis Research, 2025
- Fenger et al., anthocyanins, metal ions and blues, IJMS, 2021
- Fairbairn et al., stability of cannabis in storage, J. Pharm. Pharmacol., 1976
- Shaikh et al., UVA and UVB photolysis of cannabinoids, Molecules, 2026
- Cherki and Feng, SINTES Point no. 11, OFDT, 2026
- Legifrance, order of 30 December 2021 (article 1, I and III)
- Conseil d'Etat, decision of 29 December 2022, no. 444887
- ISO/IEC 17025, testing laboratories
Written by the Phytogrammes team
Every article in this journal draws on primary sources (ANSM, EFSA, EUR-Lex, peer-reviewed publications) and on the lab's own practice: batch-by-batch HPLC analyses, measured cannabinoid profiles. Our approach.
Article published on . CBD is not a medicine.