If you want to brew kombucha at home, everything starts with one thing: a healthy SCOBY. Get that right and the rest of the process is forgiving. Get it wrong and no amount of good tea will save the batch.
This guide covers what a SCOBY actually is, how to tell a healthy one from a failing one, what you need alongside it, and how to keep it alive between brews. We grow our cultures in-house in our own microbiology lab, so most of what follows comes from watching thousands of these things live and die.
What is a kombucha SCOBY?
SCOBY stands for Symbiotic Culture of Bacteria and Yeast. In practice it is the pale, rubbery disc that forms on the surface of fermenting sweet tea.
The disc itself is cellulose, produced by bacteria as they ferment. What matters is what lives inside it: acetic acid bacteria, lactic acid bacteria and several yeast species, all working in sequence. The yeasts break sugar down into simpler compounds; the bacteria convert those into the organic acids that give kombucha its sour bite and low pH. That low pH is also what keeps unwanted organisms out, which is why a properly acidic brew is a safe brew.
People often call the SCOBY a "mushroom" or a "mother." Neither is accurate, but both stick because the disc looks alive in a way most food ingredients don't. It is alive. Treat it accordingly.
If you want the microbiology in depth, we've written about the specific bacterial strains in kombucha and what each one does.
How to tell a healthy SCOBY from a dying one
This is the single most useful skill for a new brewer, because almost every panicked "is my SCOBY ruined?" question has an obvious answer once you know what to look at.
Signs of a healthy culture
- Creamy white to light tan in colour. Darker brown patches are usually just tea staining, not a problem.
- A smooth, even, rubbery surface. Thickness varies and doesn't indicate health.
- Brown stringy strands hanging beneath it. These are yeast colonies. They look alarming and they are completely normal — arguably a good sign.
- A sour, vinegary smell.
- Sinking, floating or standing on edge. All three are normal and none of them mean anything.
Signs of a real problem
- Mould. Fuzzy, dry, and sitting on top of the surface rather than in the liquid — usually blue, green or black, and circular. Mould is the one unambiguous failure. Discard the entire batch, SCOBY included. Don't try to scrape it off.
- A cheesy or rotten smell rather than a vinegary one.
- No activity at all after two weeks — no new layer forming, no change in taste. Usually means the culture was dead on arrival or the environment is too cold.
The most common false alarm by far is yeast strands being mistaken for mould. If it's brown, stringy and suspended in the liquid, it's yeast. If it's fuzzy, dry and sitting on the surface, it's mould.
Where to get a SCOBY in India
You have three realistic options.
1. Buy a live culture
The most reliable route. A live SCOBY arrives already active and comes with starter liquid — mature, acidic kombucha that drops the pH of your first batch immediately and protects it while fermentation gets going. Without starter liquid, a first batch is far more vulnerable to contamination.
This is what we supply. Our kombucha SCOBY is grown in our own lab in India and tested before it ships, which matters more here than in cooler climates — Indian ambient temperatures during transit are hard on a live culture, and a SCOBY that has spent a week in a hot delivery van is not the same product that left the seller.
2. Get one from another brewer
Free, and a perfectly valid way to start if you know someone brewing. The catch is that you inherit whatever is in their culture, including any drift or contamination they haven't noticed. Ask to see it before you take it, and apply the checks above.
3. Grow your own from a bottle
Possible, but only from raw, unpasteurised, unflavoured kombucha. Most kombucha sold in Indian retail is pasteurised, which kills the cultures and makes this impossible. It also takes two to four weeks and often fails on the first attempt.
If you want to taste what properly fermented kombucha should be like before committing to brewing, our raw kombucha range is unpasteurised and bottled with the culture intact.
What to look for when buying
Ignore anything a seller says about "organic" versus "conventional" SCOBYs — that distinction doesn't exist in any meaningful sense, since a SCOBY isn't farmed. What actually matters:
- Does it ship with starter liquid? Non-negotiable for a reliable first brew.
- Is it live, or dehydrated? Dehydrated cultures are cheaper to ship but need reactivating and don't always come back.
- Where was it grown? A culture grown and tested in Indian conditions handles Indian conditions better.
- Is it tested? Ask whether the seller does any microbiological testing, or whether they're simply reselling.
- How is it packed for transit? Heat exposure in transit is the main reason a SCOBY arrives dead.
What else you need
The SCOBY is the only part you can't improvise. Everything below is standard kitchen equipment.
- A glass jar, wide-mouthed, around 2–4 litres. Wide is important — the culture needs surface area and oxygen. Never use metal or plastic for fermentation; kombucha's acidity leaches from both.
- A breathable cover — a tight-weave cloth, muslin or a coffee filter, held on with a rubber band. This is the detail beginners most often get wrong: the jar must not be sealed. The culture needs air. An airtight lid will suffocate it.
- Black or green tea. Plain leaf only. Avoid teas with added oils, such as Earl Grey, and avoid herbal teas entirely — neither feeds the culture properly.
- Plain white sugar. Roughly 60g per litre. The sugar feeds the culture, not you; most of it is consumed during fermentation. Don't substitute honey, jaggery or artificial sweeteners.
- Filtered or RO water. Chlorine in municipal tap water will damage the culture.
- A wooden or plastic spoon for handling. Brief contact with stainless steel is fine; prolonged contact is not.
- Glass bottles with tight caps for the second fermentation, if you want carbonation.
If you'd rather not assemble this piece by piece, our Kombucha Brewing Mastery Kit includes the culture, jar and accessories together.
Brewing your first batch
The short version: brew strong sweet tea, cool it completely to room temperature, add the SCOBY and its starter liquid, cover with cloth, and leave it somewhere warm and dark for 7 to 14 days.
Two things kill more first batches than anything else. Adding the SCOBY to tea that is still warm — anything above body temperature will damage it. And skipping the starter liquid, which leaves the batch unprotected during the vulnerable first few days.
We've written the full process up separately: how to brew kombucha with a SCOBY, step by step.
Storing your SCOBY between brews
A SCOBY doesn't need to be brewing constantly, but it does need to stay fed and submerged.
For short gaps, leave it in the finished kombucha at room temperature. It will keep fermenting and get progressively more vinegary, which is fine — you're not going to drink that liquid, you're going to use it as starter for the next batch.
For longer gaps, set up a SCOBY hotel: a jar holding your cultures covered in mature kombucha, with a cloth lid, kept at room temperature away from direct sunlight. Top it up with fresh sweet tea every three to four weeks so the culture doesn't starve.
Two rules that matter more than the rest. Keep it submerged — a SCOBY that dries out cannot be revived. And keep it covered with cloth rather than a sealed lid, for the same reason as during brewing.
Refrigeration is a common suggestion online and we'd advise against it. Cold shocks the yeasts and the culture often struggles to recover.
Temperature, and why it matters more in India
Kombucha ferments best between roughly 20°C and 30°C. Most of India sits comfortably in that range for much of the year, which is an advantage — brewers in colder countries fight to keep their cultures warm enough.
The Indian problem is the opposite. Above about 32°C fermentation runs fast and can go sour in three or four days instead of ten, and the yeasts start to outpace the bacteria, giving a boozier, less balanced result. During peak summer, move the jar somewhere cooler and start tasting earlier.
Common questions
How long does a SCOBY last?
Indefinitely, if it's fed and kept submerged. It also reproduces — each batch grows a new layer that can be separated and used or given away. Most brewers end up with more culture than they know what to do with.
My SCOBY sank. Is it dead?
No. Sinking, floating and standing sideways are all normal and unrelated to health. Look for a new layer forming on the surface instead — that's the real indicator of activity.
There are brown strands hanging off it.
Yeast. Normal, and a sign of an active culture. Not mould.
Can I use jaggery or honey instead of sugar?
Plain white sugar gives the most predictable results. Honey carries its own microbes that can compete with the culture. Jaggery can work but ferments unevenly and is harder to judge.
How much alcohol is in homemade kombucha?
Usually under 0.5%, comparable to ripe fruit. Longer ferments and warmer temperatures push it higher.
Do I need to buy a new SCOBY for each batch?
No. One culture, cared for, will brew indefinitely. That's rather the point of it.
Getting started
A kombucha SCOBY is one of the few things you can buy once and use for years. The initial cost is the whole cost, and if you look after it you'll be giving cultures away to friends within a few months.
Our live kombucha SCOBY ships with starter liquid, grown and tested in our own lab in India.
