Growing your own SCOBY (Symbiotic Culture of Bacteria and Yeast) is a fun and fascinating project that will allow you to enjoy fresh, homemade Kombucha brewed right in your kitchen.
This is also such a fun project to show children at home. Fermentation is like magic, science, and food tech all in one! We have a guide on summer foraging and Kombucha flavouring with kids here too.
We'll walk you through the process of growing your own SCOBY using only a bottle of live Kombucha, (our sample bottles are PERFECT) and a few pieces of very basic equipment.
By following these steps, you can create a healthy SCOBY that will help you brew delicious, unlimited Kombucha for a lifetime, and you can even use our free guide on getting your Kombucha started here.
What is a SCOBY?
Before we get into the process, let's briefly explain what a SCOBY is.
A SCOBY is a Symbiotic Culture Of Bacteria and Yeast. It is the cellulose matter that forms as a jelly-like structure on top of the liquid during the fermentation.
You always need to use 'starter liquid' when making Kombucha as well as the cellulose layer, and this is essentially already fermented Kombucha.
The SCOBY and starter liquid contain the beneficial bacteria and yeasts that consume the sugar used when making authentic Kombucha, and transform it into organic acids, which is what gives Kombucha the tarty kick we all love it for.
What Kombucha should I use?
You'll need to use a bottle of live, unflavoured Kombucha to grow your SCOBY, minimum size of 330ml is what we recommend.
This means it cannot be pasteurised (check the small print), or have flavourings / additives / preservatives / sweeteners on the ingredients list. It is also best to use a freshly fermented Kombucha, that has also not been filtered.
You can look inside the bottle for any sediment sitting at the bottom. If you find one with sediment, that would be a good one to chose! Our blog here explains how to shop for a good Kombucha.
Or alternatively, if you know someone who makes their own Kombucha, ask them if they have any they could give you.
Our sample bottles are perfect for growing a SCOBY, but you'll need to use all of the liquid which means there won't be any for you to try.
Things you'll need
To grow a SCOBY, you'll need the following:
- A bottle of live, unpasteurised, and unflavoured Kombucha (minimum 330ml)
- A glass jar with a wide mouth (500ml minimum)
- A breathable lid (e.g., kitchen roll, or muslin sheet)
- Rubber band to secure the cloth
Step-by-Step Guide to Growing a SCOBY
Step 1: Choose Your Kombucha
Select a bottle of live, unpasteurised, and unflavoured Kombucha. Look for bottles that have visible sediment or mention "authentic fermentation, contains live cultures."
Step 2: Prepare Your Equipment
Wash your glass jar thoroughly with warm water and soap. Rinse it well to remove any residue. Ensure that all your utensils and hands are clean to prevent contamination.
Step 3: The Set Up
Pour a minimum of 330ml Kombucha into your clean glass jar. Make sure the jar has some space at the top for the SCOBY to grow. Cover jar with your breathable lid to keep dust and insects out while allowing air to circulate.
Step 4: Patiently Waiting ...
To speed up your SCOBY formation, you could leave your jar at the warm end of room temperature (think airing cupboards / on top of fridge / freezers / near a radiator / heat mats).
Anywhere from 18°C to 29°C is fine, it will just take a little longer at the cooler end.
Step 5: Grow Your SCOBY
1. Fermentation Time: Let the jar sit undisturbed for about 7 to 14 days. During this time, the SCOBY will first look like cling film, and maybe a bit patchy, but as it develops it will form a complete layer.
2. Check for Mould: You may grow mould if either the temperature is too low, or you use a Kombucha which was not very live. Mould can appear as dry / fluffy / powdery spots (see our SCOBY gallery here to compare healthy SCOBYs with unhealthy SCOBYs), and if you notice any mould, you must discard the SCOBY, clean all your equipment, and start over with a new bottle of live Kombucha.
Step 6: Observe the SCOBY Growth
Patience is the key here! As the SCOBY grows, it will become thicker. After 7 to 14 days, you should see a noticeable increase in the size of the SCOBY. It should be white in colour, and slimy looking.
Step 7: Use your SCOBY
We recommend letting your SCOBY grow for 3 weeks before you use it to make a batch of Kombucha. This ensures the starter liquid the SCOBY is sitting it becomes powerful enough to kickstart the fermentation when added to sweet tea.
If you're not ready to brew Kombucha immediately, you could either add some sweet tea to your jar (to top up 300ml of tea use 20 grams of sugar and 2 tea bags (green or black) and add to the jar once cooled) or top it up with some more live Kombucha (stick to the same brand you used previously).
Store the SCOBY with its breathable lid, at room temperature, and then it will keep growing stronger and stronger, ready to be put to action. Just make sure there is always enough liquid in the jar to keep the SCOBY submerged.
Possible Issues and Solutions
Mould Formation
Discard the SCOBY and start over with a new bottle of live Kombucha (try a different brand). Make sure the fermentation temperature is warm enough (above 18°C) and that you are using a live, unpasteurised, unfiltered and unflavoured Kombucha.
Ensure your equipment is cleaned before reusing. and your environment is free from contaminants.
Slow Growth
Check the temperature of your environment. Kombucha requires warmth to grow. Move the jar to a warmer spot if necessary (up to 29°C).
No Growth
Make sure you are using a LIVE Kombucha.
By following these steps, you can create a healthy SCOBY that will let you brew delicious Kombucha for months to come.