My SCOBY Is Too Thin! Here’s What To Do

Another common question in my brewing groups concerns thin SCOBYs. The scenario is usually something like this: they’ve brew a number of batches yet they can’t seem to grow a thick SCOBY.

Alternatively, this is their first batch and they’re wondering why their new SCOBY isn’t growing as thick as they’ve seen in pictures.

Whatever the case, this article will help clear the air and get things back up and running. To start off with, let’s set things straight – is a thin SCOBY necessarily a bad thing?

My SCOBY Is Thin – Should I Be Worried?

Before we get into the article let’s make sure we’re clear on two points right from the beginning:

  1. If your kombucha brew is less than 7 days old and your SCOBY is thin just wait a little longer, it will grow!
  2. Baby SCOBY can be only a few millimeters thick after the 7 days – within a few more batches they will grow thicker.
  3. If you’re still getting great tasting kombucha that you’re happy with then there is nothing to worry about.

With that out of the way, let’s cover a few SCOBY basics (if you’re interested in learning more you can check out my article here.) First off, what exactly is the SCOBY anyway?

You may be surprised to hear that the SCOBY is actually almost completely made of cellulose. The cellulose is woven together by the acetic acid producing bacteria within the kombucha. Over time, it serves as a safe haven for both the bacteria and the yeast.

The yeast provides the food, while the bacteria supplies the home.

The reason why the SCOBY is so crucial to brewing kombucha is it provides the necessary balance of yeast and bacteria to get the new brew started – the actual shape of the SCOBY doesn’t really matter!

In fact, you can cut your SCOBY up into little pieces, as long as the quantity is right you should notice no difference in your brew.

This is where we run into the first issue with thin SCOBY – the size.

Ideally, you need the right kickstart to every new brew. This primarily comes from the strong starter liquid, but the SCOBY still plays an important role. If you don’t have the right amount of SCOBY present your brew can get off to a slow start.

This is one of the reasons why so many people struggle to grow a larger SCOBY when they only have small SCOBYs available. The time required for the SCOBY to grow usually is so long that the kombucha turns to vinegar.

Why Brewing With A Thin SCOBY Can Be Difficult

It takes time for the bacteria and the yeast to develop. So it makes sense why brewing with a thin SCOBY takes longer than with a regular SCOBY.

Just imagine if you significantly cut back on the start yeast and bacteria of your brew – the entire process will just be slower.

If things start off balance it can lead to a number of problems along the way. One example is your kombucha turns to vinegar much sooner than expected. This is usually a sign that things aren’t balanced and action must be taken to bring things back into equilibrium.

This is one of the main reasons why people are getting stuck in an endless loop of thin SCOBY! If you don’t have the right starting ratios things may not go as expected.

Reasons Why Your SCOBY Is Too Thin

There are a few reasons why your SCOBY may be having difficulty growing. They are:

  • Weak starter liquid
  • Cool temperatures
  • Low populations of bacteria
Red is the starter SCOBY, blue is the first baby and the white is the second baby

Weak Starter Liquid

One of the most common mistakes new brewers make is not using strong starter liquid. Starter liquid is the sour kombucha we use to kickstart the brewing process.

Two cups of strong starter liquid is dumped into new brew to ensure the correct balance of yeast and bacteria is present right at the start.

The key word here is strong. You shouldn’t be using regular strength kombucha as your starter liquid.

Pro Tip

Don’t use regular strength kombucha as your starter liquid

The best case scenario is taking your starter liquid from your SCOBY hotel. The second preferred method is to let your leftover kombucha turn to vinegar. The easiest way to do this is to let it sit with your SCOBY for at least another 7 days after you’ve bottled.

A thin SCOBY is a sign of weak starter liquid – you just didn’t have the right kickstart your kombucha needed!

Cool Temperatures

Remember, the bacteria supply the home while the yeast supply the food. If there is no food for the bacteria they won’t be able to build the SCOBY.

What are two ways you can cut yeast production?

  1. Cut down on the sugar you use
  2. Cool the temperature

Similar to homebrewing beer, the temperature of your yeast is crucial to their productivity. Experienced brewers will tell you how their brews take just a little longer during the winter months.

This is due to the lower average temperature of your brewing vessel.

Now, if the temperature is too cool you are going to be hurting the yeast. We want to be aiming for a temperature between 68-78°F. If you are consistently below this range your yeast will not be producing the food the bacteria needs.

Pro Tip

If you’re brewing during winter try wrapping non-LED christmas lights around your vessel to raise the temperature

Low Populations Of Bacteria

While rare, it’s possible for the bacteria populations within your brew to die off. This may be due to other strains of bacteria being present or if your brew has been exposed to anti-bacterial soap.

Note, it’s fine to use soap to wash your brewing equipment, just make sure everything has been thoroughly rinsed.

This cause is hard to diagnose, so don’t be worried right off the bat.

If you’ve tried all my suggestions below and still can’t seem to work things out you are going to want to get a new SCOBY with a new set of starter liquid.

You Used The Wrong Type Of Tea

One of the most fun aspects of brewing kombucha is the flavoring. It’s exciting mixing and matching different flavor profiles and tasting the results.

This leads to many beginner brewers using flavored teas during the primary ferment.

You may be surprised to learn that this isn’t best practice. In fact, the essential oils in the flavored tea can even be harmful to the bacteria and yeast populations in your brew.

This is why I don’t recommend you use 100% flavored tea during your primary ferment. Using a home made tea blend is fine (try and shoot for a least 50% Camellia sinensis with each blend.) Find out more here.

Alternatively, you can mix the flavored tea into the bottles during the second ferment.

How To Fix A SCOBY That Is Too Thin

Before I dig into how to fix your thin SCOBY it’s important that we ask one question: are you getting kombucha that tastes the way you want?

If the answer is yes, then I recommend you just continue on brewing.

If your kombucha is lacking in anyway then you can start troubleshooting. I don’t want you to be worried just because your SCOBY doesn’t look right. If you’re using strong starter liquid then you will likely be able to brew kombucha that is perfectly fine.

As the saying goes, there’s no point on trying to fix something that isn’t broken!

Let Your Brew Sit For Longer

My first tip to thickening your SCOBY is to let it sit in the brewing vessel for longer. They way you should do this is pour in the same amount of starter liquid and sweet tea, but instead of bottling the kombucha after 7 days let the brew sit for at least 14.

Hopefully, this gives your slow SCOBY enough time to fully develop.

If your SCOBY is still too thin to your likely then just repeat this process once.

If this fixes your SCOBY you could be dealing with low brewing temperatures or an imbalance of either yeast or bacteria.

Use More Sugar

If you’ve been using 1 cup of sugar per batch, try 1.5 cups. You can even try 2 cups and let your kombucha sit for an extra 2 days (9 days instead of 7) to see if your SCOBY develops.

This solution means your yeast wasn’t getting enough nutrients. If your yeast is struggling, so is your bacteria. Remember, it’s the bacteria that produces the physical SCOBY.

If you’re having yeast problems you can also try and scoop your starter liquid from the bottom of your SCOBY hotel. This is where the old yeast lay dormant until woken up with fresh sugar.

Use A Strong Starter Liquid

Take the starter liquid from the top of your SCOBY hotel if possible. Otherwise, you should let your first batch of kombucha turn to vinegar.

This will ensure you are always using a strong batch of starter liquid that kickstarts your SCOBY into high gear.

I usually let my leftover kombucha sit for several days before I start a new batch brew. This ensures the yeast and the bacteria are hungry for your sweet tea and will begin producing kombucha (and a new SCOBY) immediately.

Replace Both Your Stater Liquid and SCOBY

The last resort is to replace your building blocks: the SCOBY and the starter liquid.

If things have somehow become unbalanced, through contact with a foreign strain of bacteria, mold, or other harmful substances, then it will be very difficult to produce regular kombucha.

The best way to solve this issue is to buy a SCOBY and starter liquid from a different source.

If you decide to go this route I also recommend only using black tea with the correct brewing temperatures and sugar ratios for your first few batches – leave the experimentation for when you have a backup supply of healthy SCOBYs in your hotel.

Thankfully, most people don’t have to go to this length to get their kombucha brewing back up and running.

If you are still having issues, or have other suggestions, please contact me in the comments below!

15 thoughts on “My SCOBY Is Too Thin! Here’s What To Do”

  1. I have been using my old SCOBY to brew kombucha because the baby SCOBY is too thin and flimsy. I threw way the too thin SCOBY. I don’t understand. I used to have nice thick baby SCOBY’s every week. It is summer and the house is at 72 but it is cold. Is it OK to use the old SCOBY to brew for weeks? I am waiting for fall to see if the house temp can be a little warmer. Where do you recommend ordering a new SCOBY?

  2. Hi, yes I haven’t produced a 1/2 inch scoby yet. Still to thin. Thanks for your suggestions. I enjoyed reading though it. Will try to take 2 cups and a nice looking scoby from my “hotel” and start a new brew . Will see if it will develop a nice thick scoby. Thank again.

  3. Hi!
    I find this helpful, in the sense of lots of information. However I am a complete beginner, and I need everything fed to me with a teaspoon. (I have tasted combucha twice, and I’m now making a baby for the first time).
    Here’s how I did it- I cleaned a class jar. I made sweet tea and poured in a bottle of captain kombucha. Covered with a “granny cap”, stuck it in my bookshelf (away from direct light, but where I can still look at it without touching). It took about a week for a film to develop. It smells faintly of vinegar in the shelf when I stick my nose in. There’s been very little development since week 1, and it’s now been 3 weeks. I *had* to touch it, and when the liquid wobbled, the film on top wobbled like jelly, and released from the edges, so I’m pretty sure it’s a scoby. The liquid is very hazy. I also see about.. 1/2cm water evaporation.
    Anyway, scoby is thin and it’s barely developed in the last 2 weeks and I’m wondering what to do. It’s cool in my house so I know it takes time but I’d expect to see some movement. I have not tried to brew with it as it’s so thin I’m pretty sure it would break if I touch it.

    Should I love it to a cupboard in the bathroom where temperatures might me a degree or two higher?
    Or should I make another two cups of sweet tea to just pour on top?
    Or both?
    Or something else?
    Or nothing
    Thanks so much for the help and this article. 🙏🏻

    • Do both! Increase the temperature and add more food for the SCOBY. It will grow! Just keep at it 🙂 Let me know if it’s not happening and I will help you get going.

  4. just read

    I have had thin scobys for a while now, KT tastes good, I harvest around 8 days. I use strong starter usually 15% by volume to sweet tea. I use a good sized scoby from my hotel.

    Now I have 3 jars going, one 2 days old, one 4 and one jar six days old.

    Heres the thing,, the scoby growth starts well and then slows. So the day 2 jar has a good scoby starting to form, and not much smaller than the 6 day jar. The day 6 jar is a bit thicker and more white but not nearly as much as it should be.

    So they start off good but seem to slow down quickly. Plenty of yeast strands underneath early on, then these thin out after day 8.

    This has been going on for a while now.

    Does this slowing off scoby growth after a good start signify anything?

    Many thanks!

    • What temperature are you brewing at? SCOBY growth can slow down in the winter if you keep your house at colder temperatures.

  5. Hi. I’m a newbie at making kombucha. At 7 days my new SCOBY is thin. The SCOBY I started with is at the bottom. I was getting some kombucha out to taste it and my new SCOBY fell apart. Is that a bad thing? Do I need to let it brew for a few more days? The taste was more on the sweet tea side. Thank you.

  6. I would think it’s slowing down bc it has exhausted the supply of sugars the yeast can attenuate, which from a brewing perspective sounds normal to me. Given enough time it’s going to happen inevitably, barring some other event that kills or puts the yeast into dormancy first

  7. Many other sources say that the longer brewed kombucha is only really ‘vinegar’ in the sense that it has reached a far lower ph than a shorter brew, which is why it provides a formidable environment for the pre-existing good bacteria in your scoby to have a leg up over potential competing bacteria that try to establish, in other words why it makes good starter liquid. But it is otherwise still very much kombucha, and if anything contains more of the good stuff we’re brewing the kombucha for, it simply is less palatable to some due to the acidity. There is no ‘correct’ time to harvest nor is 2 wks or more too long to drink, rather it’s a matter of preference based on what you want out of it and how sour you like it/are willing to tolerate (because you are getting more health benefits in exchange for that pucker, plain and simple)

  8. I was brewing a lovely batch and didn’t consider that I was leaving on a short trip and wouldn’t be back in time to start the second fermentation so I put it in the refrigerator until I got back. It is now in the cupboard where I usually put it. Will it come back or should I start over?

    • It should be fine. It’s okay to leave your SCOBY in the starter liquid if you are going away on a small trip – you just might want to trim off the extra growth if you feel like it’s gotten too large.


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