Approximately five years ago, Canadian cannabis edibles pioneer Brandon Wright ran up against a testing problem. He was producing cannabis brownies following a 2015 decision by the Supreme Court of Canada that guaranteed licensed medical patients the right to produce and possess edible cannabis products, and he wanted patients to be certain that each brownie he served contained the same very high dose of 200 mg of cannabinoid tetrahydrocannabinol (THC).
Yet, despite sending three brownies per batch for testing, his labs reported wildly different results, which confounded Wright. “I later found out they were breaking off a corner of each brownie, [reducing it to powder], and testing that,” Wright says. The problem, he eventually figured out, was “hot spots,” which may be acute in non-homogenous cannabinoid products such as brownies. Wright warns that the lack of homogeneity within a food product containing 200 mg THC means that the end product “is likely going to have micro-hot spots, even with a production process that is excellent at mixing and homogenizing.”
Cannabinoids are fat soluble and likely to cluster in small deposits within a baked good rather than being uniformly distributed, so even in an extremely potent product (200 mg is 20 times the 10 mg-per-serving limit imposed by some U.S. states), one part of such a food item may contain more or less THC than another.
Because of hot spots, a brownie containing 200 mg of THC has the cannabinoid distributed only somewhat uniformly. To get the readings Wright was looking for, his lab needed to reduce each complete brownie to homogenous powder and sample from that powder. “I could then analyze those results to determine the milligrams of THC per gram of brownie and adjust production processes accordingly,” he says.
What Makes Potency Testing of Edibles Difficult
For food and beverage producers who pivot into cannabis-infused products, traditional food-safety testing practices remain essentially the same. Yet producers of cannabis edibles and beverages face an important test particular to their industry: potency. Potency is generally measured in milligrams of active cannabinoids, such is the best-known THC (responsible for cannabis’s psychoactive effects), the popular non-impairing cannabinoid CBD, and other less-understood cannabinoids such as cannabigerol (CBG), cannabinol (CBN), and cannabichromene (CBC).
Mike Hennesy, director of innovation for Colorado edibles producer Wana Brands, notes that, in its plant form, cannabis is a very pharmacologically diverse. “You have cannabinoids; you have terpenes. Some growers have used pesticides, and it also soaks up things like heavy metals and microbials. No one piece of equipment is perfect for [testing for] any one of them,” he says. And, that’s just for testing cannabis flower. Depending on your product, testing food items for cannabinoid potency runs from complicated to extremely complicated.
For Amber Wise, PhD, the scientific director at Seattle’s Medicine Creek Analytics, the next question is this: homogenous or non-homogenous? “A gummy is really homogeneous. It’s well mixed,” Dr. Wise says. “But a chocolate chip cookie, for instance, is not.” As infused-food producers try to concoct a winning combination of cannabinoid dose and flavor profile, her lab has received a wide variety of food products to test. “We’ve received jalapeño ranch-flavored pretzels [and] caramel popcorn.”
With complex foods featuring multiple ingredients, Dr. Wise encourages producers to submit a significant number of the items for individual testing. “If you’re making cookies or brownies, sending in 20 of those and paying for 20 individual tests, [you can] see the spread of the lab you’re using,” she says. “That gives you a better idea of, if I send in any random cookie, are they going to give me a number that is a narrow range? It gives you a sense for the spread of your product and that lab together.”
The Power of Test Prep
Hennesy says that the way a lab conducts preparation for potency testing will determine the accuracy of the results. “Test prep cannot be underestimated as one of the most important variables from lab to lab,” he adds, noting that ingredient differences among products must be reflected in how labs prepare their samples for testing, or the results may be corrupted.
“But there’s no such thing as a standard sample prep,” Hennesy says. “Those are considered, essentially, trade secrets for every different lab. Every lab will have a different test prep.” So it falls to producers to work with labs to develop “robust, internal validation programs, [meaning] the lab uses several different processes to check and double-check [that] the results they’re providing you are accurate.”
Every lab can create its own validation processes, and Hennesy warns against labs that do little validation. “Everyone’s equipment is different, and everyone’s test prep is different,” he says. “A lab really should do validation on their test prep and do validation on the individual equipment they’re using. Most importantly, they should have a different validation procedure for every type of product.”
Dr. Wise agrees, calling this process “matrix-specific testing, meaning crackers are treated differently than meat is treated differently than fruit.”
To test cannabinoids, labs must extract the molecules from the food products in which they appear, but Dr. Wise says the ingredients of any given product may affect the extraction process. “It’s important that the lab you’re working with either has tested your kind of food product previously or you’re able to work with them and send them an uninfused sample and then an infused sample,” she notes. “They can run background tests to ensure that they’re getting all of the cannabinoids out of your specific product.” (She adds that producers should avoid any lab using the outdated and unscientific division of cannabis products into “Indica” and “Sativa.”)
Hennesy stresses that, if a lab doesn’t have a validation process for the specific product in question, it should work with the producer on developing validations for the exact product the producer needs tested. This is particularly important, Dr. Wise says, for beverage producers working with water-solubilized cannabinoids, such as those in nanoemulsions. Producers must be clear with their labs when they are using such cannabinoids in order to get accurate results—but the more labs know about how the product is made, the better.
“You should also be providing information to them,” Hennesy says. “The more the lab knows about what they’re actually testing and what barriers you might have created within the product-development process that could hinder testing, the easier it is for them to tailor their procedures to give more accurate results.”
Pushing the Upper Limits
In many cases, producers testing for potency are simply looking to determine the cannabinoid content of their food or beverage products so they can list it on their packaging. Yet, in some states, producers are testing against edibles potency limits. In the states of Washington and Colorado, for example, THC is capped at 10 mg per edible or beverage serving, with a maximum of 100 mg THC per package. (Under far more stringent Canadian law, THC is capped at 10 mg per package.)
In theory, the chief challenge producers should face when testing against upper limits on THC is making sure their products don’t exceed the THC limits; however, Washington-state cannabis business-intelligence expert Jim MacRae, PhD, who has published a series of reports showing “friendly labs” allowing companies to “pay for potency” in multiple states, warns that some labs are willing to fraudulently undercount cannabinoids, allowing products onto the market with more than 10 mg of THC per serving.
However, Dr. MacRae notes that, unlike falsely inflated cannabinoid content, products that are labeled 10 mg per serving but that deliver a much stronger dose are actually more desirable to many experienced consumers. He adds that increasing the THC dose in infused products—and particularly in high-end infused products with expensive ingredients, such as Belgian chocolates—might cost producers very little. “A very small fraction of the cost of the thing is the cannabinoids,” says Dr. MacRae. “If you can double that, that’s doubling the cost of only a small proportion of your product cost.” If consumers discover a product is “a stronger 10 mg per serving,” that might increase its appeal among those looking to consume more THC.
While an excess dose of cannabinoids can’t kill a consumer, the experience of consuming too much THC is acutely uncomfortable and sometimes terrifying. Because of the enormous variation in tolerance between seasoned consumers and new users, THC doses that have negligible effects on regular cannabis consumers can provoke truly unpleasant experiences for some novices. Though some consumers would welcome a “strong 10 mg” product, new users run the risk of mistakenly consuming THC at a level that could leave them in a state of discomfort, and sometimes panic.
Hennesy believes that companies can avoid being caught up in such circumstances by setting high standards for researching and selecting the labs with which they work, and not skimping on best practices—even if there isn’t yet a uniform standard for such practices. “In reality, the cannabis industry has created a lot of low-cost providers that are working to produce the cheapest, fastest test results possible,” Hennesey says. “They’re certified by a state lab, which means they’re in the clear to give you those results—even if they’re not the most accurate results out there.”
Lab testing is one of the final steps before a producer’s food item goes to market. Hennesy says it’s up to producers to treat selecting a lab with the same care they put into developing their products. In the long run, the trust will run both ways. “It’s important to have a strong relationship with your lab,” he adds. “They’ll be able to help you troubleshoot and problem solve, and even identify when test results don’t make sense.”
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