How to Brew Kombucha: A Beginner's Guide from Our Lisbon Studio

Brewing kombucha at home sounds complicated. It isn't. Once you understand what's actually happening in the jar — and you have a healthy SCOBY — the process is remarkably simple and endlessly rewarding.

This is the method we teach in our kombucha workshops in Lisbon. We've stripped it back to what actually matters.

What Is Kombucha?

Kombucha is fermented tea. You brew sweetened black or green tea, add a SCOBY (Symbiotic Culture of Bacteria and Yeast) and some starter liquid from a previous batch, and leave it to ferment for 7-14 days at room temperature.

During fermentation, the bacteria and yeast in the SCOBY consume the sugar in the tea, producing organic acids (which create the tart flavour), a small amount of alcohol, and carbon dioxide. The result is naturally fizzy, pleasantly sour, and rich in organic acids and beneficial bacteria.

What You'll Need

For First Fermentation (F1): 1 litre filtered or boiled-and-cooled water, 2 black tea bags, 60-70g white sugar, 1 SCOBY, 100ml starter liquid (kombucha from a previous batch or plain store-bought kombucha).

Equipment: Glass jar (1-2 litre), cloth cover or coffee filter + rubber band, wooden or plastic spoon.

For Second Fermentation (F2) — optional but recommended: Flip-top glass bottles, flavouring such as fruit juice, fresh ginger, berries, herbs.

Step 1: Brew the Tea

Boil 1 litre of water. Add the tea bags and steep for 5-7 minutes. Remove the bags.

Add the sugar while the tea is still hot and stir until completely dissolved. Let the sweetened tea cool to room temperature. This is important — hot liquid will kill your SCOBY.

Step 2: Add the SCOBY and Starter Liquid

Pour the cooled tea into your clean glass jar. Add the starter liquid first — this lowers the pH immediately, creating an acidic environment that protects the brew from unwanted bacteria.

Then gently place the SCOBY on top. It may float, sink, or tip sideways. All of this is normal.

Cover the jar with a cloth or coffee filter secured with a rubber band. Do not seal with a lid — the fermentation needs to breathe.

Step 3: First Fermentation (F1)

Place the jar somewhere warm (20-26°C), out of direct sunlight.

Leave for 7-14 days. Taste from day 7 onwards using a clean straw inserted past the SCOBY. You're looking for a balance of sweet and tart.

In Lisbon's warmer months, fermentation moves faster — check from day 5-6. In cooler months, allow up to 14 days.

A new SCOBY layer will form on the surface during this time — your SCOBY is growing.

Step 4: Second Fermentation (F2) — How to Get the Fizz

Remove the SCOBY and 100ml of kombucha — this is your starter liquid for the next batch.

Pour the remaining kombucha into clean flip-top bottles. Add your flavouring (a tablespoon of fruit juice, a few slices of ginger, some raspberries). Seal the bottles.

Leave at room temperature for 2-4 days. The remaining yeast will ferment the residual sugar, producing CO2 that dissolves into the liquid as carbonation.

Burp the bottles once daily to release pressure. Refrigerate when they reach the fizziness you want. They'll keep for several weeks.

Common Problems and Fixes

Not fizzy enough: More sugar in F2, or longer at room temperature before refrigerating.

Too vinegary: F1 went too long. Reduce fermentation time.

Too sweet: F1 didn't go long enough. Add a day or two.

Mould on the SCOBY: If you see fuzzy mould (green, black or pink), discard the batch and start fresh. Brown stringy bits are normal yeast strands.

What a Healthy SCOBY Looks Like

Healthy SCOBYs are beige to tan in colour, smooth on top, with brown stringy yeast on the underside. They're rubbery and relatively firm.

Learn In Person at Our Lisbon Workshop

Reading about kombucha is useful. Brewing it with experienced guidance is transformative. In our kombucha workshop in Lisbon, you'll see, smell and taste the process at multiple stages — and leave with a SCOBY and starter liquid ready to go.

Weekend sessions available. Small groups (up to 12). We demo both cultured fermentation (SCOBY-based kombucha) and wild fermentation side by side — tea and cake included.

Book a Kombucha Workshop in Lisbon