Chocolate Interferes With THC Testing, Making It Hard To Measure The Potency Of Edibles

Chocolate Interferes With THC Testing, Making It Hard To Measure The Potency Of Edibles

The next chocolatey pot edible could be more or less potent than labelled, new preliminary research suggests. It found that chocolate-based products can sometimes provide inconsistent lab readings on the amount of THC found in them.

Scientists at CW Analytical, a cannabis testing lab in California, had started to notice that their potency readings for THC — the chemical most associated with weed’s high — of the same chocolate edible were sometimes off from one another. That led them to perform an experiment. They tested two different concentrations of ground-up milk chocolate from one edible for their THC potency: a 1,000 milligram sample and a 2,000 milligram sample. They also ran the comparison tests using different volumes of a typical solvent.

Regardless of the amount of the solvent used, the team found, the average readings from the 1,000 milligram samples were higher and more accurate than those pulled from the 2,000 milligram samples. The team’s findings were presented this week at the annual American Chemical Society (ACS) conference.

“That’s rather surprising — that definitely goes against what I would consider basic statistical representation of samples,” lead author David Dawson said in a press conference on Tuesday. “Theoretically, if you have more chocolate in a vial, you should be getting a more representative idea of the sample.”

Going further, Dawson and his team ran experiments where they mixed in cannabis-free chocolate with known quantities of THC. And once again, the more chocolate there was in a vial, the less accurate the readings. That indicates strongly that it’s something about the chocolate itself that’s causing the misreadings.

The study’s results aren’t peer-reviewed yet, so a little scepticism is still warranted. And Dawson doesn’t think any of the potential discrepancies in labelling they found would pose any danger to the American public (though edibles themselves might be less safe than other forms of cannabis use). But assuming the findings do hold true, they could cause a nuisance for cannabis-testing labs as well as the industry at large.

In California, for instance, edible products rung up for testing have to be very close to the THC value placed on a label. If the product is less potent than advertised, that could trigger a costly relabelling; if it’s higher, the entire supply of edibles can be destroyed.

“It does not pose a public health concern — it’s not that crazy of a dosage difference,” said Dawson. “The actual chocolate bar might be 5 per cent stronger than what the values are, if this comes into play. [But] it might erroneously trigger a fail for the producers, which might force them to relabel.”

There needs to be more work done to figure out a surefire way to ensure accurate THC readings in their tests, Dawson said. That will involve finding out what exactly in chocolate is causing the inaccurate readings. But based on experiments done so far with chocolate bars, cocoa powder, baker’s chocolate and white chocolate, the team’s primary suspect is the ample sources of fat found in chocolate. THC, Dawson noted, is known to be fat-soluble, so enough fat in a sample might hamper the recovery of THC through their current testing methods.

In the meantime, it seems that smaller chocolate samples (1,000 milligrams) are still accurate enough for testing, though Dawson described it as a “band-aid” strategy for now.

“Obviously a larger goal is to alleviate the problem completely,” he said.