How to Make Kombucha at Home (Beginner's Guide)

Kombucha is sweet tea fermented by a SCOBY — a symbiotic culture of bacteria and yeast. The fermentation consumes most of the sugar, produces organic acids and a small amount of alcohol, and creates a pleasantly tangy, naturally fizzy drink. It’s one of the most forgiving ferments to make at home: the process is straightforward, the equipment is minimal, and once you have a healthy SCOBY and good starter liquid, each batch practically makes itself.

This guide covers the full process: ingredients, ratios, equipment, first fermentation, second fermentation, and what to watch for at each stage.

What You Need

Ingredients:

• Tea — plain black tea is the most reliable choice; green tea works too. Use 2–4 tea bags (or 4–8g loose leaf) per litre of water. Avoid herbal, flavoured, or oiled teas — they can harm the SCOBY.
• White sugar — approximately 70g per litre. White sugar is the most consistent option. Raw cane sugar works. Avoid honey, stevia, or sugar substitutes in first fermentation.
• Starter liquid — 100–200ml per litre of finished, unflavoured kombucha from a previous batch. This acidifies the brew immediately, which prevents mould.
• SCOBY — the living culture that drives fermentation.
• Water — filtered or de-chlorinated. Chlorine in tap water can stress the SCOBY over time.

Equipment:

• Large glass jar (1-litre minimum; wide-mouth works best)
• Breathable cover (cloth, coffee filter, or muslin secured with a rubber band — not a lid)
• Swing-top or screw-top glass bottles for second fermentation
• Long spoon or spatula (non-metal is better)

Use the Kombucha Brewing Calculator to scale exact amounts for any jar size.

First Fermentation: Step by Step

1. Brew the Tea

Brew your tea strong — slightly stronger than you’d drink it. For black tea, steep 3–4 bags in 750ml of boiling water for 5–7 minutes. Remove the bags (don’t squeeze them — it adds bitterness).

2. Dissolve the Sugar

While the tea is still hot, add your sugar and stir until fully dissolved. Hot tea dissolves sugar easily — don’t try to add sugar to cold liquid.

3. Cool Completely

This is non-negotiable. Hot liquid will harm or kill your SCOBY. Let the sweetened tea cool to room temperature (below 30°C / 86°F) before the next step. You can speed this up by adding cold water to bring it to volume.

4. Add Starter Liquid

Pour the cooled sweet tea into your fermentation jar. Add 100–200ml of starter liquid per litre and stir gently. The starter liquid immediately drops the pH, creating an acidic environment hostile to mould and other contaminants.

5. Add the SCOBY

Lower the SCOBY gently into the jar. It may sink, float, or tilt sideways — all of these are normal. A new SCOBY layer will typically form at the surface during fermentation.

6. Cover and Ferment

Cover the jar with your breathable cover (the SCOBY needs airflow and the CO₂ needs to escape). Secure with a rubber band. Keep the jar in a warm spot out of direct sunlight. Ideal range is 20–26°C (68–79°F).

7. Taste Daily from Day 7

Start tasting from day 7 by drawing off a small amount with a clean straw or spoon. You’re looking for a balance between sweetness and tang. It should taste like a pleasantly sour, slightly sweet tea — not vinegary, not too sweet. Most batches finish between day 7 and day 14 depending on temperature.

When it tastes right, it’s ready to bottle. Reserve 100–200ml per litre as your starter liquid for the next batch.

Second Fermentation: Building Carbonation

Second fermentation (2F) is where you add flavour and build carbonation. This is optional — you can drink first fermentation kombucha still — but most brewers prefer the fizz.

1. Bottle your kombucha into sealed glass bottles, leaving about 2–3cm of headspace.
2. Add flavouring — fruit juice, ginger slices, berries, or lemon work well. A small amount of sugar or juice gives the yeast food to produce CO₂.
3. Seal the bottles and leave at room temperature for 2–5 days.
4. Burp the bottles daily — open briefly to release excess pressure and reduce explosion risk.
5. Refrigerate when carbonated to your liking. Cold stops fermentation and holds the fizz.

Use the Second Fermentation Calculator to work out sugar and juice amounts for your target carbonation level.

Common First Batch Problems

Too vinegary: Fermented too long. Start tasting from day 7 and pull sooner next batch.

Too sweet / flat: Didn’t ferment long enough, or the room was too cold. Extend by 1–2 days and taste again.

No SCOBY formed on the surface: Normal for first batches with a thin SCOBY. A new layer will build over several batches. Focus on taste, not SCOBY thickness.

Mould on top: Fuzzy dry growth with green, black, or blue colour. Discard the batch — don’t try to rescue it. Increase your starter liquid ratio in the next batch to ensure the brew acidifies fast enough.

SCOBY is very thin: Common with new cultures. It builds up over time. A thin SCOBY still ferments effectively.

How to Know Your Kombucha is Done

Taste is the primary signal. You’re looking for a balance of mild tang and residual sweetness — like a tart apple juice or a light cider vinegar diluted with water. If it still tastes like sweet tea, it needs more time. If it tastes aggressively vinegary, it went too long.

Secondary signals: the liquid will have lightened in colour and you may see stringy yeast strands floating below the SCOBY — both are normal.

FAQs

How long does kombucha take to make? First fermentation runs 7–14 days at room temperature. Second fermentation for carbonation takes 2–5 days. Total time from start to a fizzy, flavoured kombucha is typically 10–19 days.

What is the basic kombucha ratio? A reliable starting ratio is 1 litre of brewed tea, 70g of white sugar, and 100–200ml of starter liquid. Scale up or down — the Kombucha Brewing Calculator handles any batch size.

Can I use flavoured tea for kombucha? Stick to plain black or green tea for first fermentation. Herbal teas, flavoured teas, and essential oils can inhibit or harm the SCOBY. Add flavourings in second fermentation instead.

Do I need a SCOBY to start? Yes. You need either a SCOBY from another brewer, a starter kit, or you can grow one slowly from a bottle of raw, unflavoured commercial kombucha. Growing from scratch takes 4–6 weeks.

What if my kombucha tastes too vinegary? It fermented too long or at too warm a temperature. Start tasting from day 7 next time. Warmer kitchens speed up fermentation significantly — if your room runs above 24°C, start checking at day 5.