Kombucha Best Practices
- Use hot (greater than 164°F) water to steep tea (kills vegetative pathogens if present)
- Use only clean and sanitary equipment and utensils
- Use a commercially purchased culture on first use. Reuse only cultures from kombucha that shows no signs of mold or unusual contamination
- Kombucha with a pH below 2.5 or that tastes especially acidic should not be offered to consumers. Tea should have a pH greater than 2.5, but never higher than pH 4.2
- Discard all kombucha that is showing signs of mould contamination. Do not reuse for inoculum.
- Standard operation procedures should be written out for pH measurement and calibration. A detailed process instruction sheet to instruct employees on how to make kombucha using the food safety measures outlined. These instructions should describe how employees will measure and record on a pH log
- Consumer warnings: consumers should be notified that no more than 4 oz. per day is recommended and they should not be immunocompromised. Furthermore, they should be made aware that minor amounts of alcohol may be present
- Health claims: Operators are discouraged from marketing or labelling health claims
Options to control acidity and alcohol content
As with many fermented products, a trace amount of alcohol may be present in kombucha. After it is bottled, in the absence of oxygen, the yeast will continue to degrade sucrose and fructose, and is capable of increasing carbon and producing alcohol levels greater than 0.05 per cent. Controlling factors, including temperature, acidity, glucose availability, and complementary proportions of yeast and bacteria aid in limiting anaerobic alcohol production after packaging.
Option 1: Pasteurization will kill the culture, preventing carbon dioxide or alcohol from building up in the bottles. To pasteurize, heat the kombucha to 180°F (82°C) and bottle immediately. After 30 seconds invert bottle and hold for another 30 seconds. Allow bottles to cool. Pasteurized and bottled kombucha with a pH less than or equal to 4.2 is shelf stable.
Option 2: This method relies on refrigeration and antifungal preservatives to minimize hazards and spoilage. Add 0.1 per cent sodium benzoate and 0.1 per cent potassium sorbate to kombucha with a pH less than or equal to 4.2. Keep refrigerated until use. A refrigerated shelf life will need to be determined based on eventual yeast growth,carbon dioxide and alcohol production.
Option 3: This method relies on refrigeration alone to minimize hazards and spoilage. Keep refrigerated until use. A refrigerated shelf life will need to be determined based on eventual yeast growth,carbon dioxide and alcohol production.
Adapted from: Nummer B.A. (2013) Kombucha Brewing Under the Food and Drug Administration Model Food Code: Risk Analysis and Processing Guidance. Journal of Environmental Health, 76(4): 8-11.