What is a SCOBY?
A SCOBY is a cellulose mat that houses the bacteria and yeast cultures that turn sweet tea into kombucha — the means through which kombucha replicates itself.
What is a SCOBY? · Watch on YouTube
- SCOBY = Symbiotic Culture Of Bacteria & Yeast. A new "baby" grows with almost every batch.
- Technically the culture mostly lives in the liquid (the starter tea); the mat is the "pellicle."
- You can brew successfully with strong starter tea alone — but in Ange's side-by-side tests, starter + pellicle ferments faster.
- Extras? Hotel them, share them, compost them, or even eat them.
The sourdough of tea
It's similar to how sourdough bakers keep a "mother" dough or sourdough "starter" — a unique collection of yeasts that needs to be "fed" with flour and water and is used to make more loaves. Same story here, except instead of flour and water, SCOBYs are fed with tea and sugar. And instead of producing sourdough, they produce kombucha.
Kombucha SCOBYs go by a lot of names: the mother, the mother culture, the kombucha culture, the pellicle, the pancake, and the mushroom (inaccurate — it's not a mushroom). But "SCOBY" is the most common term among home brewers.
A new baby SCOBY usually grows across the top surface of your liquid with each new batch, taking the shape of whatever vessel you brew in. Often it's attached to the original "mother" as a new layer on top — but if they're not attached, that's perfectly fine too. You can separate them to brew other gallons or to share.
SCOBYs are usually cream to light tan, browning over time. Healthy SCOBYs come in a huge variety of shapes, sizes and colors depending on the brewer, environment and ingredients. Weird-looking is normal.
What's the purpose of a SCOBY?
Many people theorize that the SCOBY forms across the top of the vessel to create a barrier between the liquid and the air above it — a bit of a "seal" that adds a layer of protection against dirt and unwanted microbes. Ange often finds her finished kombucha has a little carbonation even under a cloth cover, just because the SCOBY created a natural "lid" that let small amounts of carbon dioxide build up.
The SCOBY also acts as a "house" the bacteria and yeast can live in and latch onto. Stringy brown yeast hanging off a SCOBY is perfectly fine — those yeasts are your friend.
Do you actually need a SCOBY?
Honestly? Not necessarily — as long as you have a good amount of starter tea. In most instances, starter tea has enough yeast and bacteria to successfully inoculate your sweet tea, and you'll likely grow a new baby SCOBY across the top even if you didn't start with a mother. Ange covers this in its own video →
A lot of people (looking at you, Reddit) will nitpick over "SCOBY" vs. "pellicle": technically the symbiotic culture resides in the kombucha liquid itself, and the cellulose mat is a byproduct of fermentation. That's scientifically fair! But most home brewers call the mat the "SCOBY" and the liquid "starter tea," so this site sticks with that vernacular to avoid confusion.
For what it's worth: in Ange's side-by-side experiments — same ingredients, 2 cups of starter tea in each batch, one with a pellicle and one without — both fermented successfully, but the batch with the pellicle consistently acidified faster. That's why she still uses a pellicle in day-to-day brewing, whether or not it's technically necessary. Why not give your kombucha the best shot against mold and harmful pathogens when you've got spare pellicles anyhow?
Can I eat it? What do I do with extras?
New SCOBYs form with almost every batch, so brewers quickly end up with extras. First, save some backups in case anything happens to a brew — that's what a SCOBY hotel is for. Already stocked? Options:
- Eat it. The jury's out on whether it has much nutritional value — some think it concentrates the good bacteria and yeast, some think it's just cellulose. It is edible: a bit rubbery, with the texture of slightly overcooked squid. SCOBY fruit leather, SCOBY jellies and smoothie purees are all out there.
- Compost it!
- Share it with someone who wants to brew. How to share/transport a SCOBY →
- Make DIY skincare out of it. Kombucha beauty products →
- Run experimental brews with ingredients you wouldn't risk on your main culture.
- Feed it to pets — home brewers feed them to dogs, chickens and horses, though Ange hasn't tried it herself. (Some people even make SCOBY "leather" wallets. Also untested at YBK.)
What about SCOBYs that form in the bottle?
Baby SCOBYs can also form during second fermentation — especially around fresh fruit pieces, herbs, or pulpy purees, where they like to latch on and grow around the more "solid" objects in the bottle.
Ange doesn't mind them and just gulps them down. If there's too much pulp or you don't love the texture, strain your kombucha — that's fine too. You can't totally inhibit SCOBY growth (this is a real, raw, natural process), but the straining/minimizing guide and the flavoring guide both have tips for less sediment and smaller babies.
One rule: don't reuse baby SCOBYs that touched flavorings (even natural fruit). Flavors throw off and degrade cultures over time — toss or compost those.