The brewing issue in kombucha

Issue: BCMJ, vol. 63, No. 4, May 2021, Page 156 Council on Health Promotion

What is kombucha?

Kombucha is a popular fermented black or green tea that attracts customers with its unique mix of fruity and sweet-and-sour flavors, promises of low sugar content, and a variety of alleged health benefits. Kombucha appeared as early as 2000 years ago in China and Tibet, but only made its way to the West via repatriated Russian prisoners after World War I.[1]

Kombucha is gaining popularity

Sales approached US$1 billion in the United States in 2018, and the market is projected to reach US$6.2 billion by 2026.[2]

Is it healthy?

Part of kombucha’s popularity is that is has less sugar than soft drinks. Another selling point is the presence of the yeast and bacteria central to the fermentation process. These probiotic microbes are alleged to convey health benefits ranging from antioxidant effects and anticancer properties to reversing hair loss. To date, clinical trials have not confirmed these claims.[1,3]

Kombucha has a secret

While kombucha is marketed as a healthful beverage,[1] an inconvenient truth exists; it contains alcohol. In Canada, the ethanol content of a beverage must be below 1.1% in order for it to not be regulated as an alcoholic beverage. (In the US, beverages must be below 0.5% ethanol content.) Yet kombucha is a fermented product, and although ethanol production is much diminished once the drink leaves the factory and is refrigerated, the production of alcohol continues—more so at higher storage temperatures and sugar content. One US investigation found alcohol levels of 7%, higher than that of beer.[2] This ability of kombucha to have increased alcohol content after production has raised concern among Canadian and US health agencies, the BC Centre for Disease Control among them.[3] Indeed, class action suits have been launched over false advertising of alcohol content.[4]

The situation is particularly concerning for at-risk populations (including children and pregnant women), as consumers may often be unaware that there is alcohol in kombucha.[5]

What do we do now?

The BC Centre for Disease Control’s recent study into this issue[5] recommends that:

  • Labeling must clearly indicate alcohol content.
  • Alcohol content must be at or below 1% for the shelf life of the product.
  • Consumers be clearly informed to keep the beverage refrigerated.

Hopefully, regulators will act to ensure that kombucha stays in the market in a way that minimizes risk and allows informed adults to enjoy its unique flavors.
—Lloyd Oppel, MD


This article is the opinion of the Environmental Health Committee, a subcommittee of Doctors of BC’s Council on Health Promotion, and is not necessarily the opinion of Doctors of BC. This article has not been peer reviewed by the BCMJ Editorial Board.


1.    Amir M. You can fail a breathalyzer in BC from drinking kombucha, 2020. Accessed 7 March 2021.

2.    Lovgreen T. How much alcohol is in kombucha? BC health officials are testing to find out. Accessed 7 March 2021.

3.    Environmental Health Services, BC Centre for Disease Control. Food safety assessment of kombucha tea recipe and food safety plan. March 2020. Accessed 7 March 2021.

4.    Specialty Food Association. Kombucha’s alcohol content causes controversy. November 2015. Accessed 7 March 2021.

5.    McIntyre L, Jang SS. A study of alcohol levels in kombucha products in British Columbia. 2020. Environmental Health Services, BC Centre for Disease Control. Accessed 7 March 2021.

Lloyd Oppel, MD, MHSc, FCFP(Em). The brewing issue in kombucha. BCMJ, Vol. 63, No. 4, May, 2021, Page(s) 156 - Council on Health Promotion.

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