What is kombucha?

Key facts

• Definition. TTB: "a fermented beverage produced from a mixture of steeped tea and sugar, combined with a culture of yeast strains and bacteria". Some products add fruit juice or other flavours. [1]
• Process. In New York's guidance, tea is steeped, sugar added, the tea cooled and the culture added; it then ferments at room temperature for about 7 to 10 days. [2]
• Alcohol. Fermentation can produce 0.5% ABV or more; at that level it is regulated as an alcohol beverage in the US (see does kombucha have alcohol). [1]
• Labels. New York requires unpasteurised kombucha to be labelled "Keep Refrigerated", with the consumer warnings "Consumption of no more than 4 oz. per day is recommended" and "Product should not be consumed by immunocompromised individuals", and a statement that minor amounts of alcohol may be present. Health claims are not allowed in labelling or marketing. [2]

How is kombucha made?

1. Brew sweet tea. Tea leaves are steeped in hot water and sugar is added. [2]
2. Add the culture. Once cool, the tea gets the SCOBY and some kombucha from a previous batch. [2]
3. Ferment. About 7 to 10 days at room temperature, covered with a cloth. New York's guidance notes that fermenting beyond 10 days can make it acidic enough to be harmful. [2]
4. Check acidity and bottle. Producers measure pH; New York's guidance asks for a pH below 4.2 and not below 2.5. [2]

What does the research say about kombucha and health?

Very little in people. A systematic review published in 2019 (literature searched to July 2018) found one study reporting empirical research on kombucha in human subjects, and concluded that claimed benefits need to be tested in human clinical trials. [3] We don't give health advice; talk to a doctor or pharmacist about your own situation.

Related answers: does kombucha have alcohol · does kombucha need refrigeration

We don't give health advice. For questions about your health, talk to a doctor or pharmacist.