It's a little sweet, a little sour and, as it turns out, sometimes a bit too boozy.

It's the latter that has the B.C. Centre for Disease Control researching kombucha products in the marketplace.

The popular fermented drink often contains traces of alcohol resulting from its production process, but various conditions can boost the alcohol to levels comparable to beer even as it sits on store shelves.

It's not likely to get you tipsy, said Lorraine McIntyre, with the BCCDC, but low levels of alcohol can be a concern for those who are pregnant or breast-feeding, or have compromised immune systems, for toddlers or for people who do not wish to consume any alcohol for personal, religious or health reasons.

The BCCDC in collaboration with the British Columbia Institute of Technology (BCIT) is testing alcohol levels in 760 samples of kombucha collected from grocery stores, farmers markets and other retail and production locations across the province. The results will be published at the end of the month.

The BCCDC collected samples of kombucha from grocery stores, farmers markets, restaurants, recreation centres and at processing and manufacturing locations across B.C. between July and September. (Tina Lovgreen/CBC)

Kombucha boom

Kombucha is a fermented tea popular with Canadians who enjoy its distinctive taste — slightly acidic, slightly sweet — that some liken to apple cider. It's also touted for its probiotics, which are believed to contain some health benefits, and its lower sugar content compared to other sodas.

Global sales of the beverage hit almost $1 billion US in 2018, according to analytics company Adroit Market Research, and projections suggest sales will hit $6.2 billion US by 2026, according to Acumen Research and Consulting.

Kombucha is marketed as nonalcoholic because the level of alcohol produced during the fermentation process usually falls below the regulatory threshold.

But health officials are concerned with how much alcohol is in the carbonated drink after regulators in the U.S. and Australia found alcohol levels as high as those in beer or cider.

Kombucha is a fermented tea touted for its probiotics, which are believed to contain some health benefits, and its lower sugar content compared to other sodas. (Tina Lovgreen/CBC)

In B.C., beverages under 1 per cent alcohol by volume (ABV) are not considered to be liquor. In some provinces and in the U.S. the threshold is lower, at 0.5 per cent ABV.

In 2017, the New York Department of Agriculture and Markets examined 21 kombucha samples. It found six were above the regulatory threshold and at least two had 7 per cent ABV, which is stronger than your average beer.

The U.S. Department of the Treasury's Alcohol and Tobacco Tax and Trade Bureau found nine out of 13 products tested in 2015 were above the limit.

Alcohol is a by-product

Kombucha is made from sweetened tea — usually black or green tea — with liquid from a previous batch of kombucha and a symbiotic culture of bacteria and yeast, known as SCOBY or often referred to as "mushroom" or "tea fungus."

SCOBY, an acronym for symbiotic culture of bacteria and yeast, is used to create kombucha. (Maggie MacPherson/CBC)

Alcohol is a natural by-product of the fermentation process. But fermentation can continue after the beverage is bottled and shipped, depending on how much yeast and sugar is in it, and how it's stored.

Paula Brown is heading the testing being done in the Burnaby lab and said temperature and time play a huge role in ethanol production.

"That's one of the concerns, because you can have it in your fridge at four degrees, but some fridges are colder. Also, in a lot of retail spaces it's not a closed fridge, it's an open cabinet type of a refrigeration unit, where you can grab without opening the door, the temperature is not as controlled as a closed fridge situation," said Brown, who is also the director of BCIT's Natural Health and Food Products Research Group.

Paula Brown, director of BCIT's Natural Health and Food Products Research Group, says temperature and time play a huge role in ethanol production in kombucha drinks. (Tina Lovgreen)

She said even the smallest differences in temperature can impact alcohol levels — for example, a drink found in the back of the fridge could have less alcohol than one at the front, where it's warmer.

Different flavours also play a role in increasing or suppressing ethanol production, said Brown, and beverages closer to their expiry date could have more ethanol as they've been sitting on the shelves for longer.

"At the end of the day, the message isn't that kombucha isn't safe. It's that some kombucha has elevated ethanol levels and that could be a public safety concern," she said.

The Burnaby lab is testing 760 samples. (Tina Lovgreen/CBC)

The lab plans to come up with a set of best practices for kombucha producers to make sure their products meet regulatory requirements.

Labelling

Part of the project includes analyzing how various kombucha producers label their beverages.

The BCCDC wants there to be consistency in labelling among producers to clearly include best-before dates, to inform consumers that the drinks may include traces of alcohol, and to guide consumers and retailers to refrigerate the products to keep the alcohol levels down.

"I think it's difficult to find the labels when they're quite small," said McIntyre.

In the U.S., there have been several lawsuits over the lack of clarity in product labelling. Just last month, kombucha producer Heath-Ade agreed to pay nearly $4 million to settle two lawsuits alleging it mislabelled sugar and alcohol content.

The company denied any wrongdoing but agreed to conduct regular testing of its products and to add warning labels indicating the beverage should be refrigerated and that it may contain trace amounts of alcohol and small pieces of culture (from fermentation).

The BCCDC wants consistent labelling on all kombucha products. (Tina Lovgreen/CBC)

Pasteurization

An easy solution to controlling alcohol levels in kombucha is to pasteurize it, but producers worry doing so would defeat the purpose.

"It wouldn't affect the flavour, but many of our customers want that live culture. If you pasteurize you will lose that," said Gustavo De Mura, production manager with Oddity Kombucha.

The small Vancouver-based kombucha maker is testing its own products for alcohol levels to ensure that even products near their expiry date don't go over the regulatory threshold.