If you are new to brewing your own Kombucha at home, or if you're thinking about starting, you might be wondering how you'll know when it is ready. We're going to answer that question here, and the good news is it's super easy and you don't need any fancy equipment.
If you haven't started your Kombucha brewing journey yet, we have the perfect range of Kombucha Starter Kits to get you going! And if you've never tried a homemade Kombucha, order a free sample of ours here.
So, you’ve set up your sweet tea with your SCOBY, and placed the jar in a quiet corner. After a few days you notice bubbles, a bit of a tangy smell, and maybe even a new thin cellulose layer forming on the surface.
It looks like something is happening, but how do you know if it is done?
The truth is, there is not a single right answer, because Kombucha is alive and each batch will behave in its own unique way. That is also part of the fun of making it yourself.
But there are some very clear signs you can rely on that will help you decide when your brew is ready to drink.
Signs Your Kombucha Is Ready
These signs include the taste, colour, smell, and you can judge by the appearance of your SCOBY too.
Some people like to use pH strips, pH meters, Brix meters, or hydrometers, but these tools are not really necessary for a Kombucha home-brewer. Once you get to know your Kombucha, you will find your own rhythm, and get a good sense of the timings.
Taste Taste Taste
Taste is the simplest and most reliable method.
When you first brew your tea and add it to your fermentation vessel (if you are using the continuous brewing method which we highly recommend), it is very sweet.
As the days go by, the yeasts and bacteria transform those sugars into organic acids, carbon dioxide, and a small amount of alcohol.
The taste changes from sweet to slightly tart, and eventually to quite sour if left long enough. By sampling a small glass each day after about the fifth day, you can keep a close eye on the transformation.
If you enjoy a slightly sweet Kombucha, you might bottle it at day six or seven. If you like it sharper and tangier, you might let it go to day ten or beyond. There is no rule, only what tastes best to you (this is one of the biggest advantages of making Kombucha at home).
Colour
Colour is another helpful clue. If you use traditional teas to brew your Kombucha (green or black), the tea starts off quite dark in colour. As the fermentation happens the liquid usually lightens. Black tea Kombuchas will have a red tint to it, and green tea Kombuchas can look more like a cloudy lemonade, but the amount of change seen will depend a lot on other factors too.
Check out our huge range of Kombucha Brew Bags here, for different herbal blends and even caffeine free Kombucha.
The brew may also become cloudy, as yeast cells and bacteria move through the liquid. A new SCOBY forming on the surface of the liquid is a great sign of life, and in the continuous brewing method we advise you leave your SCOBY to grow in the jar until it needs to be split (approx. 4-6 months time).
Smell
Smell is also an excellent guide. Early on, the jar just smells like sweet tea. Within a few days, you should notice a faint yeasty aroma.
Later, as the acids build up, the smell becomes more like apple cider vinegar. A good Kombucha often smells stronger than it tastes.
Your Kombucha SCOBY
The SCOBY itself changes as the fermentation progresses. A new layer usually starts to form across the surface within the first few days. At first it may be almost invisible, like clingfilm.
Slowly it thickens, sometimes in patches to start off with, and then turns into a solid white layer.
A healthy SCOBY is a great sign that your Kombucha is fermenting properly. The only warning sign to watch out for is fuzzy, dry, powdery mould, which looks distinctly different from the smooth and slimy surface of a SCOBY (we have some photos of healthy vs. mouldy SCOBYs on our Kombucha SCOBY gallery here).
Extra Equipment
Many people wonder whether they need tools to measure acidity or sugar levels.
pH of Kombucha
One of the most common is a pH strip or pH meter.
These measure how acidic the liquid is, with Kombucha usually dropping to a safe range of about 2.5 to 3.5 pH by the time it is ready.
Some brewers find this reassuring, but it is by no means required. Your senses alone are perfectly good at telling you what stage your brew is at.
Hydrometers and Brix Meters for Kombucha
Other tools that sometimes get mentioned are the hydrometer and the Brix meter, which are usually used in wine and beer brewing.
A hydrometer measures the density of a liquid, which can give you an idea of how much sugar is left, and then that can help calculate expected alcohol levels, but the organic acids in Kombucha are thought to make this reading inaccurate.
A Brix meter (or refractometer) also measures the sugar concentration.
In theory, these tools could tell you how much sugar has been consumed and therefore how far along the Kombucha is, but in actual practice, Kombucha is a very complex mixture.
The yeast and bacteria produce organic acids and other compounds that affect the readings, so the numbers are not always accurate or easy to interpret and most home brewers end up relying on taste and smell instead.
If You Like Science
If you enjoy experimenting, you might still fancy trying out a hydrometer or Brix meter, just out of curiosity.
It can be interesting to track how the readings change over time (to compare the day 1 measurements to the day 10 measurements for example) and compare them with your own taste tests. But don’t be surprised if the numbers seem confusing and always different.
Unlike wine or beer, Kombucha does not behave in a neat, predictable way that these tools were designed for.
How Long Does It Take To Make Kombucha?
So how long does fermentation usually take? The length of time varies depending on the environment.
In a warm kitchen of around 24 to 27 degrees Celsius (75 to 80 Fahrenheit), Kombucha usually ferments in 7 to 10 days.
In cooler spaces, it can take 12 to 14 days or even more. At the start of your brewing journey, the best way to find your ideal point is to start tasting around day five and check daily from there. After a couple of successful batches, you'll find a rhythm and you'll be able to know when it's ready without tracking it so closely.
Temperature, the strength and amount of your starter liquid, and your personal taste all play a role in the speed of the fermentation, which is why it tends to differ so much from brew to brew.
What if you leave it too long?
Over-fermented Kombucha turns very sour, and essentially turns into Kombucha vinegar. This has loads of fun uses, which we have listed in detail here, and definitely isn't a wasted product.
Secondary Fermentation
It is also worth noting that Kombucha continues to change even when bottled (if left at room temperature). The yeast keeps consuming any remaining sugar, producing natural carbonation.
This is called secondary fermentation. If you bottle while the Kombucha still has some sweetness, you will likely get a fizzy, lively drink after a few days in the bottle (see our tips and tricks on getting your Kombucha fizzy here in this blog).
This stage adds another layer of decision making about when your Kombucha is “ready". Some people prefer to bottle earlier for more fizz and others wait longer for less sweetness. Check out Our Kombucha Recipe Club for over 100 different recipes for your own homemade Kombucha.
In the end, the answer to the question is simple: your Kombucha is ready when it tastes right to you.
The real joy of home brewing is learning how your Kombucha behaves in your own space and discovering the flavour that suits you best.
There are plenty of signs to reassure you along the way: the taste shifts from sweet to tart, the colour grows lighter and cloudy, the smell becomes sharper, the SCOBY thickens, and the brew bubbles gently.
Tools like pH strips, hydrometers, and Brix meters can add some scientific curiosity to the process, but they are not necessary for a successful brew.
Making kombucha is a blend of science and art. The science is in the fermentation, where microbes transform simple sweet tea into a tangy, living drink. The art is in knowing when it feels right to you, guided by your senses rather than strict measurements.
With patience and practice, you will develop confidence in your own brewing, and that moment when you take a sip and realise, “Yes, this is it” will become second nature.