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What is a SCOBY? The Ultimate Guide to Kombucha SCOBYs

One of the hardest things to figure out when I started brewing kombucha was the SCOBY. It's such a weird and unique creature. Plus information online was so scattered and I wanted to make sure I knew as much as I could so that I made my kombucha the right way.

If you’re in a similar place, this article is for you!

So what is a SCOBY?

SCOBY is an acronym that stands for Symbiotic Culture of Bacteria and Yeast. The SCOBY is a living bacteria culture used in the kombucha brewing process that turns sweet tea into kombucha by eating the sugar and caffeine in the tea, and producing alcohol, acids, and carbon dioxide.

There’s a lot to talk about when it comes to SCOBYs, including how they work, how to keep them healthy, where to get them, how to make your own, and how they can be used outside of brewing kombucha. I'll cover all these things for you in this article, but first let's start with the basics.

What is Kombucha?

Kombucha is a probiotic drink made from fermented tea that has become quite popular in recent years due to its great taste and many health benefits such as improved digestion and gut health, detoxification, and immune system strengthening.

What Exactly is a SCOBY?

The SCOBY (Symbiotic Culture of Bacteria and Yeast) is a living culture of bacteria that is used to make kombucha. The bacteria and yeast eat the sugar and nutrients in sweet tea and ferment it into alcohol, acids, and carbon dioxide to create sour kombucha.

When most people speak of the SCOBY, they’re talking about the ¼ inch to 2 inch thick jelly-like disk of living bacteria that sits on top of brewing kombucha. This disk on the surface of the booch is actually called the pellicle. 

The pellicle is a mat of cellulose, which is basically a bunch of sugar strung together by the bacteria. If you look at a pellicle through a microscope, you can actually watch the bacteria creating these strings of sugar. It’s pretty cool. 

Technically, the pellicle is part of the SCOBY, but it’s not all of it. SCOBY refers to all the bacteria and yeast present throughout the kombucha, including that in the pellicle, but also that floating through the kombucha.

How SCOBYs Work

All booch begins as sweet tea. What turns this sweet tea into sweet and sour probiotic kombucha is the SCOBY, which eats the sugar and caffeine from the sweet tea and produces acids, carbon dioxide, and alcohol.

Once it has eaten enough sugar to make the kombucha bitter tasting, the SCOBY is removed and the 1st fermentation is complete. At this point the kombucha can be drunk, but it's not carbonated or flavored yet.

The carbonation and flavor is added in a 2nd fermentation. During this stage, the kombucha is sealed in glass fermenting bottles that are filled with fruit, juice, or herbs for flavoring. 

Over the course of a few days, the kombucha in the bottles develops carbonation and flavor. It’s then refrigerated and ready to be drunk!

Where Can I Get a SCOBY?

If you’re in search of a SCOBY, there are 3 main places you can get one from, you can buy one online, get one from a friend, or make one yourself.


In my opinion, unless you have a close friend that brews their own booch, the best way to get a SCOBY is to order it online from Amazon. This is what I did when I started brewing booch and it was a great decision. 

All it takes is a click of a button and your SCOBY will be sitting on your doorstep in less than a week. The only work you really have to do is making sure you buy from a good seller, or else you’ll waste time and money trying to make kombucha with a dead or inactive SCOBY. 

If you do decide to buy a SCOBY online, I recommend buying one from Fermentaholics. This is the SCOBY I used to begin home-brewing kombucha. Their SCOBYs are USDA certified organic, come delivered alive in mature starter tea, with good size, and only cost $13. You can find Fermentaholics SCOBY on Amazon here.

Get it From a Friend

Another good way to acquire a SCOBY is to get it from someone else who brews kombucha. Since the SCOBY grows during every brew, your friend can just peel off an older layer for you to use.

This works best if you have a friend that's been home brewing for a while since they’ll have a large SCOBY, but you may even be able to find some kind of kombucha brewing community near you and get a SCOBY from them.

The kombucha community is usually very friendly, and most people will be more than happy to help a new home brewer get started. 

Make it Yourself

The last way to acquire a SCOBY is to make it yourself. This is by far my least favorite option, simply because of the time it takes.

A SCOBY needs to be at least ¼ inch thick before it’s big enough to start brewing. If you're making one at home, it will take around 30 days before the SCOBY reaches this size. Even if you do have the patience to wait that long, it’s still gonna be another 2 weeks until the actual brew is finished. That's a long time to wait just to save 13 bucks.

How to Make your Own SCOBY

If you do choose to make your own SCOBY, whether that's because you want the experience or just to say you did it, you want to make sure you do it right.

It’s a simple recipe, but the last thing anyone wants is to waste a month waiting for a SCOBY that will never form. Below is a recipe to help you make a very healthy and active SCOBY.


Bottle of Raw Unflavored Kombucha Green or Black Caffeinated Tea

2 Tablespoons of Sugar

1. Buy some raw, unflavored kombucha at your local grocery store or online. This will be our starter tea and will be the acidic environment and original bacteria from where the SCOBY will grow. 

Combine the bottle of unflavored kombucha with 1 cup of green or black caffeinated tea and two tablespoons of sugar. The sugar and nutrients in the tea will be food for the bacteria culture to grow.

2. Move the mixture into a 1 gallon glass jar and cover it with some type of cloth and a rubber band. 

Place the jar in a room temperature environment (68-80 degrees fahrenheit, 20-26.5 degrees celsius)

3. Now we wait. Check up on your SCOBY every few days to make sure that there is no mold forming. 

After about 30 days your SCOBY should be at least ¼ inch thick. If it’s not, just wait a little longer. Once your SCOBY has reached that thickness it's finished and ready to start making kombucha!

How to Handle a SCOBY

SCOBYs love to eat, which is great when they’re making our kombucha, but can be dangerous if they eat stuff they're not supposed to. Because they are really sensitive, if we feed our SCOBY anything other than sugar they can get damaged or weakened.

Even the oils on our hands can damage the SCOBY if we don’t wash them properly before touching it. So to keep your SCOBY as healthy as possible, handle it rarely and make sure nothing foreign falls into your brewing vessel. 

What Should My SCOBY Look Like?

At some point in your kombucha brewing journey, you may wonder if your SCOBY is unhealthy, moldy, or just plain dead. 

When I first started brewing booch, my SCOBY sank to the bottom of the glass jar I was using. Since all the pictures I saw online had their SCOBYs floating on the surface I thought there was something wrong with mine.

It turned out that my SCOBY was perfectly healthy and it even ended up floating to the surface a few days later. 

The point is that your SCOBY is going to look different than every other one you see online. They’re like snowflakes, each one is unique. Some are smooth and white, others are bumpy and dark. Some float on the surface, some hang out at the bottom.

Don’t worry too much about how it looks, It's bacteria after all, it’s supposed to be ugly.


The one thing you do need to watch out for when it comes to your SCOBY is mold. A lot of people worry a ton about whether or not there's mold on their SCOBY when the truth is it’s pretty rare. 

I’ve personally never had mold on my SCOBY, and on the off chance that you do, it should be pretty obvious.

Here's a few tips to help you identify mold:

1. Mold always grows on the surface

Because mold is an aerobic being (it needs air to survive) you’ll only find it on the surface of kombucha. This means that anything under the SCOBY or floating under the surface is not mold.

2. Mold’s texture is dry and fuzzy

Mold is made of tiny hair like structures known as hyphae that are fuzzy to the touch. Knowing this, we can rule out any smooth and moist parts of our SCOBY as not moldy. 

3. Mold develops in circles

Mold usually grows in clumps, circles, or rings. 

4. Mold is an interesting bright color

The SCOBY is usually brown/tan, so if you see colors of white, green, blue, or black, there could be mold developing.

White is probably the hardest to define as mold but if you use the other identifiers in this list (is it circular? fuzzy?) you should be able to identify it as mold or not.

How do I Prevent SCOBY Mold?

he good thing about mold is that with the right preventative measures, we can almost always keep it from developing.

If you’ve had moldy kombucha in the past, this short list of tips below could prevent it from growing in the future.

1. Keep Your Brewing Kombucha at The Right Temperature!

If your kombucha brew isn’t kept at a temp above 65 degrees fahrenheit (18 degrees celsius), it is very likely to develop mold. This is because low temperatures slow down the fermenting process and make the bacteria culture in your booch inactive. And if the bacteria in your booch aren't active, the brew has no acidity in it to prevent mold or other bad microorganisms from developing. 

The ideal range of temperature to keep your kombucha jar in is 75-85 degrees fahrenheit (23-29 degrees celsius). It’s usually easy to stay in this range in the summer, but “winter is coming” and if your kitchen isn’t heated enough, your home brewed booch could have some problems. 

Wrapping your brew in a blanket or towel and placing it near an appliance in a warmer area of the kitchen is one way to keep your booch warm enough. But if you’re still having a heating problem and dealing with mold and ruined brews, you could save a lot of time and money by investing in a kombucha heater. 

Kombucha heaters are heating pads made specifically for home brewing kombucha and allow you to control the temperature of your brewing booch to the degree. They’re also super energy efficient, so you can have one on 24 hours a day without worrying about your electricity bill running up. 

Hemlock home brewing makes a really good quality heating pad for 1 gallon vessels. It has 3 temperature settings that allow you to configure the heat to exactly the level you need, and has a temperature gauge that makes it easy to know exactly how your booch is doing. Plus it’s Amazon Prime eligible. You can check out Hemlocks kombucha heating wrap on Amazon here. 

2. Use Enough Starter Tea.

The whole purpose of starter tea is to give our brew acidity early on. If we don’t use enough starter tea, we have the same problem that we have if our brew is too cold: a low acidity and therefore no protection against mold growth.

I always recommend using at least 2 cups of starter tea per gallon of kombucha. If it's your first brew and you bought a SCOBY online, just use all the starter tea that it comes packaged in and you should be fine. 

3. Use the Right Kind of Tea.

I’ve already written an article on the best kind of tea to use for the healthiest and best tasting kombucha which you can check out here.

A quick overview is that you should use pure, organic, caffeinated tea to brew your kombucha. 


It turns out that the first time tea leaves are washed is when you brew them! This means that if the tea you use isn’t organic, pesticides and chemicals are likely going to end up in your kombucha.

Even if you’re not worried about consuming these chemicals yourself, you should be worried for your SCOBY. Because the SCOBY eats basically whatever you give it, if there are chemicals and pesticides in your tea, it’s going to eat them.

And because of how sensitive the SCOBY is, (even touching it with unwashed hands could damage it) if you give it something it’s not supposed to eat such as pesticides or chemicals, it’s going to die, or get weakened to the point where it can’t fight off mold growth.


The reason to use pure tea leaves to brew kombucha is that they will give you the cleanest flavor and most nutrients possible out of the tea. These extra nutrients are not only good for you, but will also be great for keeping the SCOBY healthy.

Another reason to use pure tea is that the chemicals in scented or flavored teas can hurt the SCOBY, leading to your kombucha tasting funny, the SCOBY dying, or your brew becoming moldy.


While organic and pure tea leaves will make better and healthier kombucha, they are optional. What’s not optional is that the tea you use to brew kombucha NEEDS to be caffeinated. Caffeinated tea is necessary because caffeine is one of the most important nutrients for keeping the SCOBY healthy.

4. Use Pure Sugar and Avoid Chlorinated Water.

Artificial sweeteners lack the required calorie based sugars your SCOBY needs for food. So using them in place of sugar will lead to your SCOBY dying of starvation. Use normal sugar. 

Chlorinated water is in the taps of many homes in the United States, but chlorine isn’t good for the SCOBY, so I recommend using distilled water. You can pick up a gallon for cheap at almost any grocery store. 

5. Keep Your Brewing Vessel Out of The Sun and Away From Moisture.

Your SCOBY can become damaged if stored in direct sunlight, and a moist environment is mold’s favorite place to form. A countertop away from windows in your kitchen or pantry is probably the best place to keep your brew. Just make sure the top is covered with a cloth to keep the bugs out.

If you follow these 5 tips, you should be able to keep mold away from your SCOBY forever.

You may be able to get away with not doing a few of these things right in a brew, just know that mistreating your SCOBY over time will lead to it slowly weakening until it's unable to fight off mold.

What to Do With a Moldy SCOBY

I know I told you it’s super rare that you get mold on your SCOBY. But let’s say that you did. The first thing you need to do if this happens is throw away your SCOBY and any liquid/kombucha it touched.

You can’t just peel off the moldy part of the SCOBY and save the rest because mold spores can be microscopic. If they’re in one place, the whole brew is contaminated. 

After you dispose of the SCOBY and any contaminated liquid and the brewing vessel is empty, wash it thoroughly with soap and water like you would wash your dishes. 

Once it’s cleaned with soap and rinsed, add a splash or two of distilled/pasteurized white vinegar (raw vinegar has its own bacteria cultures that will contaminate our brew) and swirl it around to coat all the interior of the jar. This process is known as “curing” and does two things:

1. Removes any soap left behind that could harm our SCOBY

2. Sets the pH of the jar to prevent mold and contaminants

After curing you don’t need to rinse the jar again, just plop in your SCOBY and starter tea and begin brewing again.

I know it sucks to have to start all over, but hopefully you can figure out what caused the mold and use the 5 tips above to figure out how to prevent it in the future. 

What You Can Do with an Old SCOBY

If you’re done home brewing kombucha, or are just peeling a few old SCOBY layers off, don't throw them away just yet. There are uses for old SCOBYs. Here are a few:

1. Eat it

Some people choose to eat their SCOBYs. If the idea of biting into a raw SCOBY doesn't sound appetizing to you, there are ways to incorporate it into normal recipes. 

Some people puree their old SCOBYs into smoothies while others make it into jellies. I’ve even heard of someone making SCOBY gummy bears! The whole purpose of eating your SCOBY is to gain the same probiotic benefits that you get from drinking kombucha, and not waste the SCOBY at the same time. 

2. Compost it

Others compost their kombucha SCOBYs because the acidic nature of the SCOBYs can help balance the pH of the soil and create a really good environment for plant growth.

3. Make a Dog Treat/Chew Toy

If you can benefit from the probiotics in kombucha, so can your pets! All you have to do to create a chew toy out of an old SCOBY is flavor it with dog friendly seasons, and then dry it in the sun until the slimy parts disappear. 

If the SCOBY is too big for your pet, chop it up! And remember to always monitor your pet while introducing new foods into their diet. 

4. Give it to a friend

My favorite thing to do with old SCOBYs, provided that they’re still alive, is give them to a friend that wants to begin brewing kombucha! Your gift of 1 SCOBY will allow them to brew kombucha forever and even give pieces of that SCOBY to friends in the future. It’s the gift that keeps on giving!

Final Thoughts

SCOBYs are unique and sometimes complicated creatures.

Hopefully this guide answered all the questions you have about them, but at the end of the day, the best way to learn is from experience. Go out and get your own SCOBY, treat it right, and it will help you make some awesome kombucha. 

If you want to learn more about kombucha, how it relates to your health, and even how to brew it yourself, check out the rest of my website!

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