DIY project | Kombucha tea

Introduction to Kombucha

If you have never tried Kombucha tea, then your missing out. It is actually a really refreshing, effervescent and yummy drink. I like drinking mine chilled, and best yet it is an awesome probiotic which improves your gut health.

As I am writing this, I’m sipping a delicious honey, ginger and lime flavoured Kombucha I made last week, and have been secondary fermenting inside a recycled water bottle.

Kombucha ferment
Not bad, especially since it costs less than 10 cents to make!

Kombucha is a powerful probiotic

Did you know a healthy gut microbiome is critical to staying healthy? Modern lifestyles and manufactured junk foods (edible food like substances) which are full of chemicals and refined sugars wreak havoc on your gut health and body, killing off good gut microbiome and allowing the bad bacteria to bloom. This in turn causes a lot of the health issues we see today, and is becoming increasingly studied by modern medicine.

Kombucha is fermented with a colony of wild bacteria and yeasts, and an incredible number of them make it through the (incredibly simple) brewing process and find their way into their new homes in your digestive system. This helps to reinforce the ‘good gut bacteria’ which help you digest your food such as certain types of human indigestible dietary fibre. In doing so, they produce beneficial compounds that your body absorbs. This is called symbiosis where two organisms work together to mutually benefit one another. Your gut microbes work with you to get the job done!

It is known that richness, abundance and diversity are three key factors for gut microbiota

Dr Purna Kashyap, Gastroenterologist.

Its considered a bit of a taboo to discuss, but did you know passing wind is a sign that you have a really healthy gut microbiome? And that the gut bacteria are actually responsible for the majority of your noxious offgassings 🤣

Why make Kombucha yourself

I have said it before, and I will say it again;

Maintaining a low cost of living is critical to maximising your savings rate and therefore the amount you can invest each month. The lower you can get your cost of living, the higher your savings rate and the quicker you will reach Financial Independence

Captain FI (…or maybe Captain obvious!?)

I find it absolutely ridiculous that there are bottles of kombucha selling for over $5 each at grocery stores. Especially when the total cost of a batch of 5 x 600ml bottles of my Kombucha costs me around 50c to make!

Ingredients to make Kombucha

The basic ingredients to make kombucha are;

  • Sugar: 1 cup to 3-4L of water (approximately – precision doesn’t matter)
  • Tea: 6 teabags worth of strong tea to 3-4L
  • Kombucha SCOBY:
  • Fruit flavourings as whatever your heart desires

This seems like a ridiculous amount of sugar to add, but rest assured by the time kombucha has finished fermenting and is ready to drink, its sugar content is actually very low meaning you don’t consume any of it!

How to make Kombucha

To make kombucha, you essentially ferment iced tea. You introduce a SCOBY (Symbiotic Colony Of Bacteria and Yeast) and some starter tea (kombucha from a previous batch) to a room temperature sugary tea solution in an open vessel and leave it for about a week. It’s important to add the starter tea as this lowers the pH level (it is acidic) to a level the SCOBY prefers – in a pinch you could probably add a capful of apple cider vinegar but the Kombucha from a previous batch is preferred.

Putting a tea towel over the jar and fastening with a rubber band is the best solution to stop stuff getting in but keep airflow into the vessel. The good bugs get to work eating the sugar and tea, multiplying, and turning the sweet tea solution into a fizzy, tangy and aromatic (I think it smells like peaches!) drink.

Kombucha ferment
Loose lid or fasten a tea towel over it to allow airflow into the vessel to prevent it from fermenting anaerobically and turning into moonshine!

There is some complex chemistry and biology, going on in here (such as the production of acetic acid) but its important you follow the steps outlined (open vessel is important) as otherwise you might end up with a bit of home-made moonshine and turn your Kombucha into an alcoholic cocktail, or even worse be at risk of nasty pathogens infecting your brew!

After a week when your primary fermentation has finished, you can take your SCOBY out and add fruit and close up your jar to trap the bubbles in and make it more fizzy, OR you can do what I do and decant your kombucha tea into individual bottles and place your flavouring fruit into these such as a slice of lemon or lime. I prefer doing it this way, and then store these bottles in the cupboard to let them ‘carb up’ (carbonate and get nice and fizzy).

I don’t bother cleaning out the primary fermentation vessel, and simply top it up with new sugary tea solution to start the next batch. Make sure you leave some of your tea solution in with the SCOBY to help kick start the next batch.

Cost breakdown to make Kombucha

To make my kombucha, I roughly budget that a kilo of sugar costs $1 at my local supermarket, and a 100 pack of black or green tea bags costs somewhere between $2.50 to $5.00. To flavour I usually add a few bits of chopped up fruit, such as slices of lemon or lime which are very cheap.

Realistically, these are the only main costs to making Kombucha, and using the above ingredient ratios means the recurring cost (without flavouring) is about 35 to 60 cents per 3-4L batch depending how fancy you get with the secondary fermentation fruit you add. I make 3L batches, and get 5x600ml bottles out of it every week. This means my unit cost is usually around 10c per bottle!

A Kombucha SCOBY will probably set you back about $10 (unless you get one from your friend for free). You can nurture your own by buying one of those fancy supermarket $5 kombucha bottles and using that as the source of bacteria and yeast to grow your first batch.

If you do this it’s probably just going to take longer; having a big mother SCOBY will rapidly increase your fermentation times. Once you have a SCOBY, you can even cut it in half or quarters to give away portions to your friends , or even try selling them. I have made over $100 selling Kombucha SCOBYs in my neighbourhood for $10 each, as well as given away countless others.

Dangers of Kombucha

Making your own kombucha can go wrong. It can turn out highly alcoholic if you add too much sugar and seal it up, and bottles can even explode if they carbonate up too much. My advice is test and adjust, and if you have any worries about the potential safety aspect then either give it a miss, or do some more research about properly brewing it.

I have also read articles online about the dangers of food poisoning and things like botulism from ingredients like raw honey being used in Kombucha, so I would probably recommend you don’t give it to infants or small children, and pregnant or breastfeeding mothers might want to give it a miss too.

The safety net here here is the SCOBY produces a low pH environment (acidic) in the tea. Properly brewed Kombucha has a pH of around 2.5-3.5, which tends to kill off nasty pathogens which might make you sick – but if you make it incorrectly and the pH isn’t low enough there could be a risk. The anti-microbial action of the compounds in fermented Kombucha also work to fight off any nasty pathogens.

Generally, as long as your Kombucha is below 4 its pretty safe, you might want to buy a pH testing kit or just let it brew for a bit longer to get it really tangy (acidic/sour) to make sure its safe to drink.


Making Kombucha is great fun and an awesome home project. You can use a glass jar, bottles or buy a Dual Drinks Dispenser like I did from Kmart for $20. Kombucha is good for you, and tastes great. You can have fun tinkering and adjusting the recipes and times to suit your taste. Making it at home is a great way to keep your living costs low and maximise your savings rate, helping you reach Financial Independence quicker!


Have you ever made Kombucha? I am always looking for new flavourings or techniques, let me know if you have any great ideas in the comments below!

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