How to make kombucha at home: a step-by-step guide

To make kombucha at home, you brew sweet tea, let it cool, add some mature kombucha from a previous batch (the starter liquid) plus a SCOBY if you have one, cover the jar with cloth and leave it at 20–29 °C for 7–14 days. The two things that matter most are hygiene and acidity: the starter immediately drops the pH below 4.6, which keeps unwanted microbes out. Below is everything a beginner needs for a 4 L batch.

What do you need to make kombucha?

The equipment list is short, but everything must be clean:

• A 5 L wide-mouth glass jar (or a food-grade stainless steel vessel)
• A tightly woven cotton cloth or coffee filter and a rubber band
• A pot for brewing, plus a wooden or plastic spoon
• Pressure-rated glass bottles with good caps (for second fermentation)
• Ideally a pH meter or pH strips covering roughly 2–6

Ingredients for a 4 L batch

Ingredient	Amount	Notes
Water	~3.6 L	Boil or filter chlorinated tap water
Black or green tea	16–20 g (8–10 bags)	~4–5 g per litre
White sugar (sucrose)	280–320 g	~70–80 g per litre
Starter liquid (mature kombucha)	~400 mL	~10% of the batch, tart and unflavoured
SCOBY	1	No SCOBY? See below

These ratios match published guidance for small producers: the New York State Department of Agriculture lists 4–5 g of tea per litre, 50–150 g of sugar per litre and roughly 10% starter.

How to make kombucha at home, step by step

1. Clean everything. Wash the jar, spoon and your hands with hot soapy water and rinse well. Leftover antibacterial soap or bleach can harm the culture.
2. Brew the tea. Bring about 1 L of water to the boil, take it off the heat, add the tea and steep for 10 minutes. Remove the bags or strain the leaves.
3. Dissolve the sugar completely in the hot tea.
4. Cool it down. Add the remaining ~2.6 L of cold water. Do not add the culture until the tea is below 30 °C; hot tea kills it.
5. Add the starter liquid. Stir in 400 mL of mature kombucha. This is the most important safety step because it acidifies the batch straight away.
6. Add the SCOBY with clean hands. Whether it floats, sinks or turns sideways does not matter.
7. Cover and wait. Secure the cloth with a rubber band and place the jar somewhere ventilated, out of direct sunlight, at 20–29 °C.
8. Taste. From day 7, take a sample from the side with a clean straw or cup. When the sweetness has faded and the tartness is clear, it is ready.
9. Reserve and bottle. Set aside the SCOBY and about 400 mL of kombucha for the next batch. Bottle the rest and refrigerate, or flavour and carbonate it with a second fermentation.

What temperature, time and pH should you aim for?

Kombucha is a living culture; temperature and acidity drive the whole process.

Parameter	Target	Why it matters
Fermentation temperature	20–29 °C (sweet spot ~24–27 °C)	Below 20 °C slows the culture and raises mold risk; above 30 °C it turns vinegary fast
Time	7–14 days	Depends on temperature, starter strength and taste
pH after adding starter	≤ 4.6, ideally around 4.5 or lower	4.6 is the food-safety line between acid and low-acid foods
pH by the end of week one	≤ 4.2	Used as a critical limit in producer guidance
Finished kombucha	~pH 2.5–3.5	Below 2.5 is too acidic to drink

The pH 4.6 figure is the US regulatory boundary for acid and acidified foods. For kombucha specifically, Virginia Cooperative Extension advises that the brew reach pH 4.2 or lower during fermentation but never fall below 2.5, and the Pennsylvania Department of Agriculture recommends discarding a batch that has not reached 4.2 within seven days. pH strips are not mandatory at home, but they are cheap and take the guesswork out of your first batches.

How to make kombucha without a SCOBY

No SCOBY? A bottle of raw, unflavoured, unpasteurised kombucha will do:

1. Make 1 L of sweet tea using the ratios above and let it cool.
2. Add 200–250 mL of raw kombucha; the extra starter acidifies the tea quickly.
3. Cover and keep at 22–27 °C. Within days a thin, translucent film appears on the surface; in 2–4 weeks it grows a few millimetres thick.
4. That new SCOBY and the soured liquid become the starter for your first 4 L batch.

If the label says pasteurised or filtered, or the product has a shelf life of many months at room temperature, there is probably no live culture and this method will not work.

Can you use hibiscus or other flavours?

Hibiscus gives kombucha a ruby colour and a bright, cranberry-like tartness. The easiest approach is to finish the first fermentation with regular tea, then add 1–2 g of dried hibiscus per bottle during the second fermentation. If you want hibiscus in the first fermentation, keep at least three-quarters of the tea as true tea: the culture relies on nutrients from Camellia sinensis and weakens over time on herbal infusions alone.

What should you NOT use?

• Glazed ceramic crocks and decorative pottery. Acidic kombucha can dissolve lead from glazes; a couple in Australia who brewed in a ceramic pot developed lead poisoning that required treatment.
• Reactive metals. Aluminium, copper, iron or galvanised containers and utensils react with acid. Food-grade stainless steel (304/316) is safe, which is why commercial tanks use it.
• Non-food-grade or scratched old plastic.
• Honey, herbal or flavoured teas in the first fermentation. They make results unpredictable. Stick to plain sucrose and plain tea while you learn.

Is it mold or normal growth?

The most common beginner question.

Normal	Mold (discard the batch)
Thin, translucent or cream-coloured new layer that looks wet	Dry, fuzzy, raised patches like cotton wool
Brown, stringy yeast strands hanging below	Round blue, green, black or pink colonies
Bubbles, holes, lumpy or uneven surface	Spots growing on top of the SCOBY, on a dry surface
Light vinegar and yeasty smell	Musty, earthy or cheesy off-smell

If you see mold, do not rinse the SCOBY or cut off the patch. Throw away the liquid and the culture, clean the jar thoroughly and start again with a fresh culture. The usual culprits are too little starter (pH stays high) and a cold room.

Safety notes

• Only start new batches from a clean culture with no visible problems.
• Refrigerate finished kombucha. In our Fethiye brewery we keep live kombucha at 2–4 °C all the way to the customer.
• Bottles can over-pressurise and burst during second fermentation; use pressure-rated bottles and check them daily.
• Alcohol in homemade kombucha is not measured; see our article on kombucha alcohol content.
• If you are pregnant, immunocompromised, or have kidney or liver disease, talk to your doctor before drinking homemade, unpasteurised beverages. A 1995 CDC report described two people who fell severely ill after drinking home-brewed kombucha; no causal link was established, but moderation is sensible.

Start at home, then scale up

Homebrewing kombucha takes a clean jar, a strong starter, the right temperature and a little patience. Your first few batches will teach you how your kitchen behaves. If you would rather skip the jar, try the live kombucha we brew in Fethiye. And if you are thinking of turning the hobby into a business, our production setup page explains how commercial kombucha plants are planned, from tanks and cooling to hygiene.