How to Make Kombucha
How to Make Kombucha at Home
The Short Answer
To make kombucha at home, brew sweetened black or green tea, allow it to cool completely, then add your live SCOBY and starter liquid. Cover with a breathable cloth and leave to ferment at room temperature for 7 to 14 days. Taste from day 7 and bottle once it reaches your preferred balance of sweet and sour. A second fermentation in sealed bottles with fruit or ginger builds the natural fizz.
Getting your first batch right comes down to four fundamentals: the quality of your tea and sugar, the acidity of your starter liquid, consistent temperature and proper airflow. Get these right and kombucha is one of the most straightforward fermented drinks you can make at home. This guide covers each one in plain language so your first batch gives you the result you are after.
Kombucha Ingredients and Ratios: Getting the Foundation Right
Every ingredient in kombucha serves a specific purpose. Sugar is the primary food source for the SCOBY, tea provides the nitrogen, vitamins and antimicrobial compounds the culture needs to stay healthy, and water makes up the bulk of the brew. Getting the quality and ratios of each right from the start gives your SCOBY the best possible environment to ferment consistently and produce a great tasting drink every time.
Use organic cane sugar where possible as it gives the culture clean, reliable fuel without residual chemicals. Loose leaf or bagged black tea works best for beginners as it produces a well balanced ferment without excessive bitterness. Always use filtered or still mineral water, tap water contains chlorine and other additives that can stress or weaken a live culture over time, particularly in the early batches.
| Batch Size | Water (Filtered) | Organic Sugar | Tea Bags | Starter Liquid |
|---|---|---|---|---|
| 1 Litre | 900ml | 60g | 3 Bags | 100ml |
| 2 Litre | 1800ml | 120g | 6 Bags | 200ml |
| 3 Litre | 2700ml | 180g | 9 Bags | 300ml |
| 5 Litre | 4500ml | 300g | 15 Bags | 500ml |
NutriBrew Tip: Do not over steep your tea. Around 10 to 15 minutes is all you need. Steeping for too long releases excess tannins which can make your finished kombucha bitter and harsh rather than clean and balanced.
How to Ferment Kombucha: The First Fermentation Explained
First fermentation is where the magic happens. Over 7 to 14 days your SCOBY consumes the sugar and tea, converting them into organic acids, B vitamins and beneficial live cultures. The sweet tea you started with gradually transforms into something tangy, complex and completely different. Understanding what is happening at each stage helps you make better decisions and produce a more consistent brew.
Step by Step: First Fermentation
Step 1: Brew your tea
Heat your filtered water to just below boiling. Stir in the sugar until fully dissolved, then add your tea bags and steep for 10 to 15 minutes. Remove the bags and allow the liquid to cool completely to room temperature before doing anything else.
Step 2: Add your SCOBY and starter liquid
Pour the cooled tea into your fermentation jar, then add your live SCOBY and starter liquid. Never add a SCOBY to warm or hot tea. Even mild heat can stress or kill the culture instantly and there is no recovering from it.
Step 3: Cover with a breathable cloth
Cover the jar with a piece of muslin cloth or a coffee filter secured with a rubber band. Do not use an airtight lid. Kombucha needs airflow during first fermentation to develop properly. The cloth keeps dust and insects out while allowing the brew to breathe.
Step 4: Find the right spot
Place the jar somewhere away from direct sunlight and away from strong smelling foods. In an Irish kitchen, aim for a temperature between 20 and 26°C. Cooler than this and the fermentation slows considerably. Warmer and it can move too fast and become overly sour.
Step 5: Wait and observe
Leave the brew undisturbed for 7 to 14 days. Around day 7 you will notice a new translucent SCOBY layer forming on the surface. This is a good sign. Taste test from day 7 onwards using a clean straw until you find the balance of sweet and sour that suits you, then move to bottling.
NutriBrew Tip: In Ireland, kitchens can be cooler than ideal during winter months. If your fermentation is taking longer than 14 days, try moving the jar to a slightly warmer spot such as on top of a fridge or near a boiler. A few degrees makes a significant difference to fermentation speed.
How to Know When Your Kombucha is Ready to Harvest
There is no universal finish line for kombucha. Readiness comes down to personal taste, and the only way to know is to try it. Some people prefer a lighter, slightly sweet brew harvested around day 7. Others like a sharper, more vinegary flavour that develops closer to day 14. Both are correct. Your palate is the only tool that matters here.
The Taste Test Method
From day 7 onwards, dip a clean straw into the brew, cover the top with your finger to trap a small amount, and taste it.
Still quite sweet: Leave for another 2 to 3 days and taste again.
Balanced, tangy with a little sweetness: This is the ideal harvest point for most people.
Very sour or vinegary: Harvest immediately. You can still use it as strong starter liquid for your next batch even if it is too sour to drink on its own.
The Baby SCOBY: What it Means and What to Do with It
By the end of your first ferment you will likely notice a new layer of culture forming on the surface of the liquid. This is commonly called a baby SCOBY and it is a sign that your culture is healthy and actively reproducing. Some batches produce a thick, defined new layer. Others produce something thin and barely visible. Both outcomes are normal and neither affects the quality of your kombucha.
Once you are ready to start your next batch, you can use either the original SCOBY, the new layer, or both together. Over time you will accumulate more SCOBY than you need, which is a good problem to have. The surplus can be passed on to friends or family who want to start brewing, composted, or used in certain recipes.
NutriBrew Tip: Keep a small jar of finished kombucha in the fridge as your starter liquid reserve. Every new batch needs around 10% starter liquid to lower the pH immediately and protect the brew from unwanted bacteria in the early days of fermentation. Never run out of it.
How to Carbonate and Bottle Your Kombucha
After first fermentation your kombucha is tangy and alive but largely flat. Carbonation builds during a second fermentation in sealed bottles, where the remaining yeast continues to produce carbon dioxide with nowhere to escape. The result is a naturally fizzy drink with a flavour you can customise completely. Our full guide to kombucha second fermentation covers this process in detail.
Bottling Your Kombucha
Step 1: Choose the right bottles
Use swing top glass bottles. They are designed to handle the pressure that builds during carbonation safely and can be reused indefinitely. Avoid regular screw top bottles as they are not built for pressure and can crack or leak.
Step 2: Add flavour if desired
Before sealing, add a small amount of fruit juice, fresh fruit, ginger or honey to each bottle. This gives the yeast additional sugar to produce carbonation and adds flavour at the same time. Browse our kombucha recipes for flavour combination ideas.
Step 3: Leave the right amount of headspace
Fill each bottle leaving around 2 to 3cm of air at the top. This gap is essential. Without it there is no room for carbonation to build and the pressure has nowhere to go safely.
Step 4: Seal and leave at room temperature for 2 to 3 days
Leave the sealed bottles at room temperature for 2 to 3 days to allow carbonation to build. Burp each bottle once daily by opening it slightly to release excess pressure, particularly in warmer kitchens above 22°C.
Step 5: Refrigerate to lock in the fizz
Once your kombucha has reached the level of carbonation you want, move the bottles to the fridge. Cold temperatures slow fermentation right down and lock the bubbles in. Always open bottles slowly over a sink the first time, particularly in warmer weather.
💧 You may notice brown stringy strands floating in your bottled kombucha. These are natural yeast clusters produced during fermentation and are completely harmless. They are actually a sign of a healthy, active brew. You can strain them out before drinking if you prefer a cleaner pour.
Common Questions From First Time Kombucha Brewers
Brewing your first batch always raises questions. Here are the ones we hear most often from new brewers, answered clearly so you can brew with confidence. For a full library of troubleshooting, SCOBY care and storage questions, visit our dedicated Kombucha FAQ and Troubleshooting Guide.
My SCOBY arrived and looks strange. Is it still good?
Yes, almost certainly. A fresh SCOBY can look quite different to what people expect. It may be brown, unevenly shaped, have dark streaks running through it or feel rubbery and uneven in thickness. All of these are normal. The only thing to look for is fuzzy dry growth in green, black or white, which would indicate mould. Brown patches, strings and an uneven surface are signs of a healthy, active culture and not cause for concern.
Do I need a specific jar to brew kombucha?
A wide mouthed glass jar works best. The wide opening gives the SCOBY maximum surface area to grow and allows good airflow through the cloth cover. Most home brewers use a 2 to 5 litre glass jar. Avoid plastic containers as they can harbour bacteria and may interact with the acidity of the brew over time. Metal containers should never be used as the acids in kombucha will react with the metal and damage the culture.
What is starter liquid and why does my first batch need it?
Starter liquid is simply finished kombucha from a previous batch, or the liquid your SCOBY arrived in. Its job is to lower the pH of your sweet tea immediately at the start of fermentation, creating an acidic environment where the SCOBY can thrive and mould cannot take hold. Without starter liquid your brew is vulnerable in the first 24 to 48 hours. Always add at least 10% starter liquid by volume to every new batch before you add your SCOBY.
Why does my kombucha smell like vinegar? Is something wrong?
No, a vinegary smell is a sign that fermentation is working. The bacteria in your SCOBY produce acetic acid as part of the fermentation process, which smells distinctly like vinegar. If the smell is very strong it usually means the brew has fermented for longer than needed or the kitchen is warmer than 26°C and the cycle has moved faster than expected. Taste it using the straw test. If it is too sour for drinking, use it as potent starter liquid for your next batch rather than discarding it.
Can I use green tea instead of black tea?
Yes. Green tea produces a lighter, slightly more delicate kombucha with a milder flavour than black tea. Both contain the tannins, nitrogen and caffeine that the SCOBY needs to stay healthy. Some brewers use a blend of black and green tea to get a balanced flavour with a little more complexity. Avoid flavoured teas such as Earl Grey, fruit teas or herbal blends as the essential oils and additives in these can stress or weaken the culture over time.
How much kombucha does one SCOBY make?
A single NutriBrew SCOBY can ferment anywhere from 1 to 5 litres of kombucha per batch depending on the size ordered. Most home brewers start with a 2 litre batch, which produces roughly 8 to 10 glasses of finished kombucha after accounting for the starter liquid you keep back for your next brew. As your SCOBY grows and you become more confident with the process, you can scale up your batch size at any time.