Kombucha is made by fermenting sweetened tea with a SCOBY — a symbiotic culture of bacteria and yeast — plus a splash of starter liquid, and learning how to brew kombucha at home really comes down to a two-stage process: a first ferment that turns sweet tea pleasantly tart, then an optional second ferment that builds fizz and flavor. This guide walks the whole homemade kombucha routine step by step, with a working ratio, an equipment list, and the safety points that genuinely matter.
Home fermenting is forgiving once you understand what the culture is doing, but it is still a live, raw process. Read the safety section before you start, and treat every batch with clean hands and clean glass.
What kombucha is (the short version)
Kombucha starts as ordinary sweet tea. You add a SCOBY and some already-fermented starter liquid, and over a week or two the bacteria and yeast eat most of the sugar and turn it into acids, a little carbon dioxide, and a trace of alcohol. The result is a tangy, lightly effervescent drink that some people enjoy for its bright, sour taste and its living cultures.
This is a genuine fermentation, not a quick infusion. If you want a no-fermentation cold tea instead, that is a different technique — see cold brew tea. And because kombucha is built on real tea leaves, it helps to understand the plant behind it: black, green, white, and oolong all come from Camellia sinensis, the tea plant.
What you need: equipment and ingredients
The gear is deliberately simple, and the material choices are the part that matters most. Fermentation is acidic, so you want inert, food-safe surfaces.
- A large glass jar (a wide-mouth glass vessel is ideal). Avoid reactive metal and questionable glazed ceramic — acid can leach from unsuitable materials.
- A tight-woven cloth cover and a rubber band. The cloth lets the culture breathe while keeping out dust, lint, and fruit flies. Do not seal the first ferment with an airtight lid.
- A kombucha SCOBY plus starter liquid — either from a previous batch, a friend, or a reputable source. The starter (mature, acidic kombucha) protects the young batch while it gets going.
- Plain tea made from Camellia sinensis. Black or green work best. Avoid flavored or oiled teas such as Earl Grey for the culture itself — the added oils can harm the SCOBY over time.
- Plain white cane sugar. This feeds the culture. Honey, artificial sweeteners, and most sugar substitutes do not work the same way, so keep the base simple.
- Bottles with tight caps for the optional second ferment (swing-top bottles are popular for holding carbonation).
If you are new to steeping strong tea for the base, the fundamentals in how to make tea carry straight over. Black tea in particular gives a classic, robust kombucha — more on the leaf in what is black tea.
How to brew kombucha: the first ferment (1F)
This is the core kombucha recipe — the stage that actually makes the drink. A common, easy-to-scale rough guide for a one-gallon batch is about 1 cup of sugar and roughly 8 tea bags (or the loose-leaf equivalent) per gallon of water, plus at least 1 to 2 cups of starter liquid. Treat those numbers as a starting point; brewers adjust to taste, and stronger or weaker tea changes the result.
- Brew strong sweet tea. Heat your water, steep the tea to make a strong concentrate, then stir in the sugar until fully dissolved. Removing the tea after steeping keeps it from turning harsh.
- Cool it to room temperature. This step is non-negotiable — hot liquid will kill the SCOBY. Wait until the sweet tea is genuinely at room temperature (roughly 68–85°F / 20–29°C) before going further. Diluting the concentrate with cool water speeds this up.
- Combine in a clean glass jar. Pour the cooled sweet tea into your jar, then add the kombucha SCOBY and the starter liquid. Clean hands, clean jar — every time.
- Cover and wait. Secure the tight-woven cloth with a band and set the jar somewhere at steady room temperature, out of direct sunlight, undisturbed, for about 7 to 14 days. Warmer rooms ferment faster; cooler rooms slower.
- Taste from around day 7. Use a clean straw or spoon. The flavor should move from sweet toward pleasantly tart. When it tastes balanced to you — not cloying, not harshly vinegary — the first ferment is done.
A new baby SCOBY often forms across the surface during 1F. That is normal and healthy, not mold. When you bottle, reserve the SCOBY and a couple of cups of the finished kombucha to start your next batch.
The second ferment (2F): fizz and flavor
The second ferment kombucha stage is optional but popular, because it builds natural carbonation and lets you flavor the drink.
- Bottle it. Pour the finished kombucha into clean bottles with tight-sealing caps, leaving about half an inch to an inch of headspace at the top.
- Add a little flavor. A small amount of fruit, fruit juice, or fresh ginger gives the yeast a bit more sugar to work with, which is what creates the fizz.
- Seal and wait 2 to 5 days. Keep the sealed bottles at room temperature. Warmer means faster carbonation.
- Burp the bottles. Pressure builds during 2F. Open each bottle briefly once a day to release excess gas — this prevents over-pressurized bottles.
- Refrigerate. Chilling slows fermentation and locks in the carbonation. Strain out flavoring if you prefer, and enjoy cold.
Timeline at a glance
| Stage | What to do | Rough time |
|---|---|---|
| Brew & cool | Steep strong tea, dissolve sugar, cool to room temp | 1–3 hours |
| First ferment (1F) | SCOBY + starter in covered glass jar; taste from day 7 | 7–14 days |
| Bottle | Fill bottles, add fruit/juice, reserve SCOBY + starter | ~15 minutes |
| Second ferment (2F) | Sealed bottles at room temp; burp daily | 2–5 days |
| Chill | Refrigerate to hold fizz and slow fermentation | Ongoing |
Keeping a SCOBY between batches
Your SCOBY is reusable and, with care, effectively long-lived. Between batches, store it submerged in a couple of cups of finished kombucha (a "SCOBY hotel") in clean glass at room temperature. It thickens and layers over time; you can peel layers apart to share or thin the culture. If it ever smells cheesy or looks fuzzy, do not use it.
Safety: brew it responsibly
Home-fermented drinks are generally rewarding, but they carry real, if small, risks, so a few rules keep every batch on the safe side:
- Keep everything clean and non-reactive. Use clean hands and thoroughly cleaned glass equipment. Avoid reactive metal and unknown glazed ceramics, which can react with the acid.
- Cover with breathable cloth, never an airtight lid, during 1F. The culture needs airflow, and a tight weave keeps contaminants out.
- Watch for mold. Healthy kombucha may look cloudy and grow a pale new layer, and brown yeast strands are normal. But if you see fuzzy, dry mold — often blue, green, black, or white and fluffy, sitting on top — discard the entire batch and the SCOBY, and start over. When in doubt, throw it out.
- Do not over-ferment, and burp your bottles. Too long a ferment turns it sharply vinegary, and un-burped 2F bottles can build excess pressure.
- Remember it is fermented. Kombucha contains a trace of alcohol from fermentation (home brews vary and can rise higher than commercial versions), and it retains some caffeine from the tea. Both vary by batch and brew time.
This is general information, not medical or health advice. Kombucha is a raw, home-fermented product, and people who are pregnant or breastfeeding, who are immunocompromised, or who are simply unsure should check with a qualified professional before drinking it — and anyone can choose a well-made commercial bottle instead of a home brew.
Where to go from here
Once your first few batches land where you like them, the fun is in the variables: the tea you start with, the length of the first ferment, and the fruit you add in the second. Nail the sweet-tea base first — the same care you would put into a good pot of tea pays off here — and the rest is patience and tasting. Brew a batch, take notes, and let your palate tell you when the next one is ready.