How Safe Is It… to brew kombucha at home?

Kombucha is a fizzy, bubbly drink known for its tart taste, and made from fermented sweet tea.

Fermentation is a natural technique used to make a variety of foods and drinks. The process happens when a carbohydrate, such as sugar, chemically interacts with bacteria or fungi to create alcohol or acid. Common foods made by fermentation include yogurt, kimchi, sauerkraut, and sourdough bread.

To make kombucha, brewed tea and sugar interact with a culture that contains bacteria and yeast called a SCOBY (symbiotic colony of bacteria and yeast). When the sweetened tea interacts with the SCOBY over time, kombucha forms. Probiotics develop during fermentation, which are bacteria that play a positive role in gut health.

Bottles of kombucha sold at grocery stores are made in giant batches in factories. They brew tea in large steel kettles, add sugar, and then mix the sweet tea with various flavorings. You can also make kombucha at home in smaller amounts. Making kombucha at home is less expensive over time, and you can customize flavors. A challenge to brewing kombucha at home is that you are dealing with bacteria, which has the potential to be harmful.

The SCOBY used to make kombucha contain living bacteria, which poses potential risks. Mold can grow on the SCOBY for a variety of reasons, such as fermentation occurring at too high or low of a temperature, improper storage, or use of flavorings that encourage mold growth. This mold can cause allergic reactions or illnesses and can be poisonous, although it is not deadly. If there is mold on your SCOBY, throw out the SCOBY and the kombucha right away.

Overall, following careful kombucha-making directions is key to reducing the risk of mold occurring–and if mold appears, it’s best to throw out your SCOBY and kombucha, carefully test your process, and start over.

Tips to prevent mold if you make kombucha at home:

  • Use clean tools and utensils
  • Ensure a mold-free environment
  • Ferment at 68-78 degrees Fahrenheit
  • Keep the kombucha spaced away from anything else fermenting
  • Use correct proportions of ingredients