If you’re diving into the world of kombucha brewing, you’ve likely heard of a SCOBY. But what exactly is it, how does it work — and do you really need one to get started?
In this guide, we’ll cover:
What a SCOBY is
How it contributes to kombucha fermentation
What it looks like (and what’s normal or not)
Plus: tips to help beginners brew confidently at home
🧫 What Is a SCOBY?
SCOBY stands for Symbiotic Culture of Bacteria and Yeast — it’s the living community that transforms sweet tea into kombucha.
After a few days of fermentation, a thin film starts forming on top of the tea. Over time, this thickens into a rubbery, jelly-like disc — often beige or light brown in color. You might also hear it called a kombucha mushroom or kombucha mother (though it’s not actually a fungus).
Each time you brew, a new “baby SCOBY” forms on top — continuing the fermentation cycle and SCOBY disc becomes thicker.
SCOBY ARCHITECTURE:
Starter liquid (active, unflavored kombucha)
Pellicle – the jelly-like disc that forms at the surface
Yeast – visible strands that often settle at the bottom
❓ Do You Need a SCOBY disc to Start Brewing Kombucha?
Not necessarily! You can begin brewing kombucha using raw, unflavored kombucha with live cultures as your starter. Over several days, a new SCOBY will naturally form.
🧪 Tip: Most store-bought kombucha is pasteurized and won’t work.
So while a SCOBY stabilizes fermentation, it’s not required to begin — it will grow on its own if the setup is right.
⚙️ How a SCOBY Works in Kombucha Fermentation
Inside the SCOBY, bacteria and yeast feed on sugar and nutrients in the tea. As they metabolize it, they produce:
Acids (like acetic and gluconic acid)
Carbon dioxide (which makes kombucha fizzy)
Probiotics (beneficial bacteria for gut health)
a trace of alcohol
B vitamins.
🌀 SCOBY Shapes and Variations
Not two SCOBYs look the same — and that’s part of the magic.
Shape and thickness are influenced by:
Jar shape and size
Whether you started with a SCOBY or just starter liquid
Type of tea and sugar
Temperature and environment
Don’t be alarmed by uneven, lumpy, or thickened SCOBYs — it’s all part of their natural growth.
👀 What Does a SCOBY Look Like?
A healthy SCOBY goes through visible stages. Don’t worry — it’s supposed to look a little odd!
Early Stages
In the early stages, the cultures are only present in the liquid starter mixed with sugary tea. But after a few days, a thin film begins to form on the surface.
Floating bits or strands in the liquid
Yeast colonies forming
Thin film on the surface
Bubbles
What a Healthy, Mature SCOBY Looks Like
Texture & Feel:
Smooth or slightly lumpy
Cloudy, rubbery, and jelly-like
Color:
White to light beige (can be darker if thick)
Green/white tea → lighter SCOBY
Black tea → darker SCOBY
Bits of tea in the SCOBY? Totally normal!
Smell & Signs:
Vinegary smell and light fizz — good signs!
Brown stringy yeast is normal (can float, sink, or stick to the SCOBY)
Growth:
Grows thicker over time
Can be pulled apart in layers
May sink — that’s okay! A new SCOBY will grow on top
Watch Out (but don’t worry):
Kahm yeast: thin white/creamy layer — not mold, not harmful
⚠️ How to Tell If Your SCOBY Has Mold
Mold is very rare in kombucha thanks to its acidity, but it’s still important to know the signs
🧼 Mold in Kombucha:
Appears only on the surface
Looks fuzzy, dusty, or hairy
Often white, green, blue, or black
May come with no fizz or off-smell
There is no sour taste or smell, no signs of fermentation, no bubbles!
If you’re unsure, wait a few days. If it gets clearly fuzzy or colorful, discard the batch, clean your equipment thoroughly, and start again.
🧡 In Summary
The SCOBY is the heart of kombucha brewing. It may look strange at first, but it’s a powerful community of microbes that transform sweet tea into a tangy, fizzy, gut-friendly drink.
With the right conditions, basic cleanliness, and a bit of patience, anyone can grow a SCOBY at home — and start making delicious, healthy kombucha from scratch.
🫖 Ready to Start Brewing?
Get everything you need with our kombucha kits — perfect for beginners.
Join thousands of happy home brewers who love the satisfaction of fermenting their own kombucha!
