(KSTP) – Minnesota’s budding THC beverage industry has faced a few growing pains — one being concerns with canning the drinks.

The worry: possibly losing the drink’s potency due to the plastic liner inside of aluminum cans.

That liner is there for a reason — protecting the beverage and consumer from the metal. But as more THC beverage manufacturers get into the business, they’re learning their drinks on the shelves may not hold the amount of THC advertised if not packaged right.

“It is a well-documented phenomenon. It’s known by a few different names — we call it degradation of cannabinoids,” said Max Johnson, technical sales manager with BevSource.

From quality assurance testing to determining which container works best for a beverage, Johnson says about half of all THC drinks on Minnesota shelves have come through their lab, making them well aware of the impact that liner can have on these drinks.

“The real challenge is that that plastic liner is actually electronically attracted to the ingredient that holds the cannabis,” Johnson said. “What happens over time, is that the cannabis has actually pulled it towards the walls of the can so that when a consumer drinks the product, they’re drinking the liquid that is holding it, but they’re not actually consuming the cannabis.”

Simply put, THC drinks can lose potency because of that liner.

It’s an issue that’s affected manufacturer Clr!ty firsthand.

On the heels of their best month ever in January, CEO Scott O’Malley spoke to 5 EYEWITNESS NEWS about a batch he had to pull in late 2022 due to a drop in potency.

“That was our third month of being in business,” O’Malley said. “There were a lot of speed bumps.”

He said after testing, they found that the batch had lost around 30% of its potency.

“[We then] started on the path and trying to mitigate that and find solutions,” O’Malley added.

That included putting more THC in their drinks to compensate for the degrading potency, according to O’Malley.

“That first week is where most of the degradation starts. So it’s like a hockey stick [chart], it’s a fairly steep drop off, and then it plays out for a while, so you can get one-year shelf stability,” O’Malley said.

Also, O’Malley says they now test at least three times, including one month after canning.

Another THC drink manufacturer well aware of this is Fulton Beer.

The Minneapolis brewery has two THC options that both come in glass bottles. Owner Ryan Petz says they already had the infrastructure in place to bottle the drinks, and after doing research on the topic, it was the clear choice.

“We are trying to do everything we can to make sure that what we say on the package is what is actually in the liquid,” Petz says.

He and the Fulton team are so dedicated to that goal, they’ve created a website to highlight this topic and their testing.

While state law requires the companies that offer these products to test their potency, it doesn’t outline when to test or how frequently.

The Minnesota Department of Health is overseeing these products while the new Office of Cannabis Management is finalized. MDH sent the following statement when inquired about what testing, if any, it does:

“The Minnesota Department of Health (MDH) currently has authority to regulate hemp-derived cannabinoid products including beverages. MDH does not test beverages. The manufacturer is responsible for testing each batch of product, which is required to be tested for the amount of cannabinoids, mold, solvents, pesticides, fertilizers and heavy metals.”

Minnesota Department of Health