The summer of 2021 could have been the first big season of cannabis-infused beverages if people could only have grabbed a six-pack from stores, says one eastern Ontario seller.

Brad Stewart, co-founder of Molecule, a business based in Lansdowne, Ont., says people in the industry have been left scratching their heads by the way Health Canada calculates the amount of marijuana in an infused drink.

Using Health Canada's calculations, a 355 ml drink is considered to have the equivalent of slightly more than five grams of cannabis, even though one beverage can only contain a maximum of 10 mg of THC, the psychoactive chemical in the marijuana plant.

And because Canadians can also only carry 30 grams of cannabis out of a store, it's illegal to sell more than five 350 ml drinks at a time — frustratingly shy, Stewart said, of the six-pack many consumers are accustomed to buying.

"The [regulations] almost seem like a mistake," he said. 

"For anyone specifically focused only on cannabis beverages, it's particularly challenging."

Stewart says Health Canada's calculations are unfair because they only take into account the total volume of a drink, regardless of how much THC was used in its production. 

The Cannabis Council of Canada, which has launched a campaign against the regulations, claims the role weight plays in Health Canada's measurements has created a lopsided marketplace. 

It says that, based on those measurements, consumers could only buy five cannabis-infused drinks — but they could walk out of a store with 100 bottles of cannabis oil spray. 

Rules are arbitrary, says lawyer

Trina Fraser, a partner with Ottawa-based law firm Brazeau Seller, which specializes in cannabis law, says Health Canada seems to have followed the lead of some U.S. states when crafting the regulations. 

"I think there's just many in the industry who don't understand the rationale of that policy decision," she said. 

"Cannabis-infused beverage manufacturers have been lobbying the government hard to change these equivalent ratios because they, again, are arbitrary."

ealth Canada says it has been seeking input about the limits for cannabis beverages — whether they should be increased, by how much, and what public health and public safety evidence would support such a change.

"Health Canada is now actively considering the input received from a broad range of stakeholders and individuals during these consultations," a spokesperson told CBC News by email. 

Fraser said these sorts of barriers are counterproductive to Health Canada's stated goal of displacing the illicit market. 

"If the concern is about impairment and intoxication from cannabis products, that's inherently linked to the amount of THC present," she said.

"So why isn't that the driving force behind the limits on how much you can carry in public?"