Making Kombucha SCOBY and Safety Tips

If you’ve ever sipped kombucha, you’re probably familiar with the mushroom-like blob known as a SCOBY. Its name is an acronym for “symbiotic culture of bacteria and yeast,” which activates the fermentation process that gives kombucha its fizzy texture and probiotic properties. It’s said that these probiotic bacteria play a key role in the tea’s supposed health benefits, such as improved digestion and stronger immunity.

Often referred to as a “mother” or a “mushroom,” a SCOBY typically takes about two weeks to form. You can create your own SCOBY at home, then reuse that SCOBY each time you brew a new batch of kombucha.

scoby for kombucha
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How to Make Your Own SCOBY

When home-brewing kombucha, some people opt to buy a SCOBY online or from natural-foods stores—or, in some cases, source their SCOBY from a friend. Another alternative is to make your own SCOBY, which is a fairly simple process.

  1. For best results when making your own SCOBY, use a one-gallon glass jar as your fermentation vessel. Before you get started, make sure to sterilize the jar by boiling it over high heat for about 10 minutes.
  2. Next, you’ll need to prepare a batch of tea. After bringing eight cups of water to boil in a saucepan, stir in one cup of granulated sugar.
  3. Once the sugar has dissolved, turn off the heat and drop eight bags of green tea or black tea into the saucepan. Let the tea steep for about 30 minutes.
  4. When the tea has reached room temperature, remove the tea bags and discard them.
  5. Next, pour two cups of unflavored, store-bought kombucha into your glass jar.
  6. After adding your homemade tea, fill the rest of the jar with cool water.
  7. Cover with a double layer of cheesecloth or other tightly woven fabric. Secure the cover with rubber bands to keep out dust and fruit flies.

Within about two weeks, your SCOBY should form on the surface of the tea. Wait until your SCOBY grows to a quarter-inch in thickness before removing it from the jar. In some cases, it can take up to four weeks for the SCOBY to fully form.

Once your SCOBY is ready, you can use it to brew your own batch of kombucha. Since it’s too sour to drink, the tea used to prepare your SCOBY should be discarded.


For successful SCOBY-making, try these expert tips:

  • Shield your SCOBY. Because sunlight can disrupt the fermentation process, it’s best to place your SCOBY jar in a sun-free space.
  • Always go for glass jars. If you use a metal container, acids produced during fermentation may corrode the metal and taint your tea.
  • Stick with sugar. You may prefer the taste of honey, but granulated sugar is better suited for the fermentation process. Sugar substitutes and artificial sweeteners are also a no-go.
  • Keep it plain and simple. Unflavored black and green teas are ideal when it comes to SCOBY preparation. Many flavored teas contain aromatic oils, which can interfere with fermentation.
  • Watch your SCOBY size. Your SCOBY will reproduce each time you brew a new batch of kombucha. To keep your SCOBY from getting too thick, peel apart the layers after each batch is complete. You can pass the SCOBY on to another home-brewer, or even repurpose it as an all-natural ingredient in homemade beauty products. (Some kombucha lovers recommend using the SCOBY in do-it-yourself facial masks, which may help with exfoliation.)

Safety Tips

Although SCOBY preparation is generally safe when performed properly, there’s always the risk of mold contamination. Scientists have found that these molds could be toxic, with the potential to be especially harmful to individuals with suppressed immune systems, such as HIV patients.

To prevent mold contamination, you should continually monitor your SCOBY and watch out for warning signs like a rotten or rancid smell or the growth of black or green spots. If you suspect that mold has formed on your SCOBY, toss out the batch immediately.

It’s also important to note that drinking kombucha to treat or control an existing health problem may have serious consequences. While some preliminary research shows that the brew may protect against certain health conditions (such as diabetes and high cholesterol), there’s not enough scientific evidence to recommend kombucha for any health-related purposes.

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Article Sources
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  3. Kapp JM, Sumner W. Kombucha: a systematic review of the empirical evidence of human health benefit. Ann Epidemiol. 2019;30:66-70. doi:10.1016/j.annepidem.2018.11.001