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Kombucha SCOBY: The Ultimate Beginner's Guide

Researched and Written by:
Richelle Godwin, RDN Richelle Godwin, RDN

A kombucha SCOBY looks kinda like a weird jellyfish that floats around in your kombucha jar. But guess two SCOBYs are the same They can each vary in their texture, color and smell. And whenever my clients start to make their own kombucha, the first thing they usually ask is “What does a healthy scoby actually look like?”. Well, in this article, I’m going to answer this, plus your other most popular questions about kombucha SCOBYs. Let’s go!

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Table of Contents

    What is a SCOBY?

    So a SCOBY is a collection of good bacteria and yeast that we use to ferment sweetened tea and turn it into kombucha.  Basically it works similar to how kefir grains work for kefir, which I talk about in the article.

    Now, the name SCOBY is actually just an acronym and stands for symbiotic culture of bacteria and yeast. 

    You might also hear a SCOBY referred to as a Kombucha culture, Mother culture or Tea fungus - although that doesn’t sound as appetizing! 

    And here’s the cool thing - when you place your SCOBY in sweetened tea, your bacteria & yeast buddies will get to work and feed on the sugar to create beneficial probiotics, enzymes and lots of helpful acids like these:

    Acetic acid, gluconic acid, glucuronic acid, lactic acid, citric acid, tartaric acid, usnic acid, malonic acid, malic acid, pyruvic acid, gallic acid.

    A lot, right!  Best of all, these can help with everything from antioxidant support to balancing the bacteria in your large intestine! 

    In other words, your humble little SCOBY is a bit like Harry Potter. It has these magical powers to transform simple sweetened tea into a fizzy and healthy carbonated beverage. For all the benefits of kombucha, check out this article.

    Meaning, armed with a SCOBY, you can make your own gut-nourishing Kombucha at home for next to nothing. 

    And to all of you $5 bottles of kombucha at Wholefoods...see you later!

    What does a healthy SCOBY look like?

    So I think the easiest way to explain this is to show you a healthy SCOBY I have with me now.

    As you can see...

    • It has a Light-ish color
    • It has Grown to the edges of the brewing container.  This is really important because it means that the SCOBY is protecting the liquid from the air.   
    • As you can see it is also quite Thick and this is because it has been growing - another sign of good health.
    • On the top here you can also see it has a kinda Wet & shimmering surface.  Now I know it doesn’t look particularly attractive, but guess what...this is the SCOBY letting us know it is hydrated and being fed well.
    • Now, the camera is not going to pick up on this, but there are also some small Bumps or bubbles on the surface of the SCOBY.  This means fermentation is taking place and gas is being created.  Another sign of a healthy SCOBY.
    • Finally, let’s do the smell test.  A healthy SCOBY like this Smells sweet, sour & slightly vinegar-y.  This means the bacteria are alive and fermenting away.  

    How can I tell if my SCOBY has gone bad?

    I have to laugh when clients send me photos of their SCOBYs and ask “Has it turned bad…am I a bad SCOBY parent?”.  Thankfully, it is pretty easy to spot an off-SCOBY.  In fact, let’s take a look at one now. 

    So as you can see..

    • It is turning black in color
    • It has in fact stopped growing
    • It looks a bit dry
    • Most of all there are visible signs of dry & fuzzy mold on top of the SCOBY.  Now, depending on what type of mold grows, it can be either blue, green, white or black in color.  Or if you’re really lucky, a combination of them! 
    • And finally, there is the smell test.  You see, a bad SCOBY will smell terrible.  It might give you hints of feet, cheese, and even a waft of boys' locker rooms.   All stuff you never want to smell from your SCOBY.

    It should go without saying, if your SCOBY ever gets like this, throw it out, along with any liquid it’s in. 

    How can I prevent mold growth?

    To prevent mold growth on your SCOBY, there are 4 main things you can do:

    • First up, keep your SCOBY submerged at room temperature, ideally between 68 - 78°F or 20 - 25°C.  That’s important, because if it gets too cold, fermentation can slow down and give mold an opportunity to grow. 
    • Next, make sure your SCOBY is in a Brewing container that has a cover on it, to avoid exposure to contaminants like smoke, dust, fruit flies etc. 
    • Just as importantly, the cover needs to be porous, meaning it can allow oxygen through. Something like a coffee filter, or paper works for this.  From personal experience, I use a cotton kitchen towel - the weave is large enough to let oxygen in, while being small enough that bugs can’t get in.
    • Finally, try to Avoid touching or otherwise disturbing your SCOBY.  A continuous brewing setup will help with this - which I have here.  And if you ever have to touch your SCOBY, make sure your hands, nails, utensils and jars are clean.  

    Now, I don’t personally do this, since I’ve brewed many a kombucha. 

    But if you want to really protect your SCOBY, then test your kombucha regularly with pH strips – kind of like how you would test a swimming pool to see if it is safe.  Ideally you want to see a pH range of 2.5 - 3.5. This means your kombucha is nice and acidic.

    Where can I source my SCOBY?

    Unless you have kombucha brewing buddies nearby, the easiest way to get your hands on a healthy SCOBY is Online. Websites selling SCOBYs will either ship the SCOBY in a starter liquid or dehydrated form. 

    I prefer the Starter liquid option, because it is ready to use when it arrives, has less chance of growing mold and you can use the starter tea it comes in for the first batch.    

    The other option would be to head to your local health food store or a farmer’s market, as they sometimes sell SCOBYs submerged in a starter tea.

    And the great thing about local stores and markets is they usually have someone with kombucha brewing expertise who can answer any questions you have.

    Can I grow my own SCOBY?

    When the research team at Essential Stacks and I were preparing for this article, we geeked out on this question because it is a pretty amazing thing right – we’re talking about fermenting tea and growing a baby SCOBY, without having a mother SCOBY!  Anyways, we put on our mad scientist hats and tested it out for you.

    So what we did was take some kombucha from a previous batch. You can also use unflavored store-bought kombucha.  This formed the basis of our starter and provided the source of bacteria and yeast.  Then we added sweetened tea to it and let it ferment away for a few weeks. 

    During this time a very thin and almost clear-colored film of SCOBY formed on the top of the liquid. Which you can see in a picture I took here. And this was our new baby SCOBY. As it continues to grow into a mother scoby it will become more opaque, thicker and of course better at turning fresh sweetened tea into kombucha.

    And if you want our detailed recipe for growing your own SCOBY at home, check the link in the description below.

    Do I need to separate layers of SCOBY?

    So let’s have another look at our SCOBY friend here. 

    As you can see, it is starting to form some layers.  But over time, more layers are going to appear. 

    So when it gets to this point, the big question is, what do we do?

    Well, if your SCOBY gets too big, then it will Start blocking oxygen from reaching your tea, and this will hurt the fermentation process. 

    So every 3-6 months, just like you would go to the hairdresser for a styling, you should take your SCOBY out and trim it. 

    You usually want to reduce it by half, depending on the size.  And you can do this with sterilized scissors or a serrated knife, or simply break it apart with clean hands. Which I will now demonstrate.

    Once done you can return it to its container. As for the excess SCOBY, you can either set up a second fermenting container or, if you’re feeling generous, give it away to a friend.   

    How many times can I use my SCOBY?

    Well, the good news is, our beautiful little SCOBY can be used indefinitely.  If you want to turn your SCOBY into a lifelong friend, here’s what you need to do…

    • Keep Feeding it sweetened tea, as this is what it lives on.
    • Keep Giving it enough oxygen, as this is what it uses to ferment.
    • Keep it at an Even room temperature, as this ensures it grows steadily.
    • Protect it from any contaminants like dust, dirt, smoke or mold.
    • And finally, if you want to Flavor your kombucha with fruits or use non-caffeinated herbal teas, do this as a second fermentation in a separate brewing container - away from your SCOBY. 

    Now, unless you are going to go full Breaking Bad and turn your kitchen into a pristine fermentation laboratory, your SCOBY is probably going to struggle to get this level of love.  And it will likely degrade slowly over time and eventually go bad. 

    At which time, you will need to say some nice words of thanks for your SCOBY friend as they go to little SCOBY heaven.  But the good news is, you can usually replace them with their little baby SCOBYS.  Which are the new layers of SCOBY that grow on top. 

    Our conclusion

    When you first saw our little SCOBY at the start of this article, I bet you thought “I am not having that weird jellyfish-looking thing anywhere near my kitchen!”. 

    But as we started diving into how this colony of good bacteria and yeast works…how it can keep transforming simple sweetened tea into fizzy & delicious kombucha…we kinda fell in love, right?  It really is magical.  

    So if you want to make your own kombucha and save a lotta money on that crazy-priced store-bought kombucha, then get your SCOBY game on and enjoy the fizzy freedom of home-made brew!


    Evidence Based

    An evidence hierarchy is followed to ensure conclusions are formed off of the most up-to-date and well-designed studies available. We aim to reference studies conducted within the past five years when possible.

    • Systematic review or meta-analysis of randomized controlled trials
    • Randomized controlled trials
    • Controlled trials without randomization
    • Case-control (retrospective) and cohort (prospective) studies
    • A systematic review of descriptive, qualitative, or mixed-method studies
    • A single descriptive, qualitative, or mixed-method study
    • Studies without controls, case reports, and case series
    • Animal research
    • In vitro research

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