Growing a SCOBY from Scratch

(For the New, the Bold, and the Tragically Friendless)

Nestled deep within the Realm of Brew Wild, between frosted peaks and rolling hills, lie the SCOBY Growlands™. Here, young cultures are cultivated, strengthened, and prepared for their rite of fermentation. Every serious brewer must eventually make the pilgrimage to this sacred site to study the ancient origins of the SCOBY.

Why? Because the heart of every good kombucha brew is the SCOBY. But sooner or later, every brewer finds themselves asking the same question:

What is a SCOBY… and how do you grow one?

 

In the beginning... there was SCOBY

If you recall from our Kombucha 101 Guide, SCOBY stands for Symbiotic Culture Of Bacteria and Yeast. So when we say “grow a SCOBY,” what we really mean is taking existing kombucha liquid and allowing the culture within to mature and multiply.

That mature liquid is given a very unexciting, but highly practical name: starter liquid. (Because it starts fermentation. No expense was spared naming this thing.)

Some people assume “growing a SCOBY” means growing the pellicle (the rubbery, slimy disc that forms on top of the brew). While the pellicle isn’t strictly necessary for fermentation, many brewers choose to keep the same one around for many brews.

You can brew with a pellicle or without one. There’s no wrong answer here, but despite its dramatic appearance, the pellicle’s primary role isn’t actually fermentation. Its role is more defensive, acting as a shield between your kombucha and unwanted visitors like mold, dust, and fruit flies.

 

Ancient brewers once referred to starter liquid as Initium Liquidum. Legend says uttering the phrase aloud can summon a powerful SCOBY shield.

 

Whether you start with a pellicle or not, new pellicles will always form during active fermentation.

In Batch Brewing, where you start with only liquid starter, one of the first signs that fermentation has begun is a thin pellicle forming across the surface.

In Continuous Brewing, where the pellicle is reused between batches, new layers continue forming on top of the old one. That’s why long-running kombucha cultures can develop a pellicle of legendary thickness, or as we like to call it, SCOBY armor.

 

Try breaching these walls, we dare you.

Choose Your Fighter

So, you’re the kombucha pioneer in your social circle. Or perhaps… you don’t have a social circle. (You can always start a kombucha blog. Not speaking from experience.)

Fear not, lonely brewer. If you live near a grocery store, you already have access to kombucha starter liquid. You’ll just need to be a little choosy, much like you are with your friends.

Do we have friends? No. But our standards remain high. 

Here’s what to look for when selecting kombucha (not friends):

1. It’s best if raw.

Some brands pasteurize or micro-filter their kombucha, which can weaken or reduce the live cultures in the bottle. That can make fermentation slower, weaker, or less predictable.

2. Fresher is better.

Smaller or local brands are often fresher and less likely to be heavily filtered or heat-treated before bottling. That doesn’t mean larger brands can’t work… but some come out of the bottle more battle ready than others.

3. Trust your taste.

Different kombucha brands can produce noticeably different flavors, acidity levels, and fermentation behavior. That means the starter you choose can influence the character of future batches, so it helps to begin with a brand you already enjoy drinking.

Want proof that not all starters are equal? We put several store-bought kombucha brands through a series of brewing trials to see how they performed as starter cultures. 

Watch Battle of the Booch

Grow Your Own: The SCOBY Starter Saga

Step One: Forage your local grocery store for a wild, untamed kombucha in its natural habitat: the refrigerated section.

Step Two: Bring your newly captured kombucha home and pour it into a small jar or glass (16–32oz is ideal). Leave at least an inch of headspace at the top so the SCOBY can breathe.

Step Three: Cover the jar with a breathable cloth (like a cotton sheet) and secure it with a rubber band. This keeps out dust, fruit flies, and other threats lurking in your kitchen air.

Step Four: Place the jar somewhere warm and dry. A heat mat works wonders here. SCOBYs love consistent warmth, and the cozier they are, the faster they grow.

Now, we wait.

 

Early-stage pellicle formation. Very dainty, very demure.

 

If a new pellicle starts forming after about a week (look for a thin, almost invisible, jelly-like layer across the surface), congratulations! That means your culture is alive and active.

Don’t worry about growing a full pellicle just yet. You don’t actually need one to brew. You’re simply confirming that the starter culture is viable and active.

If nothing appears after 10–12 days, the culture may be too weak to reliably ferment on its own. But don’t give up yet. As long as there’s no mold, sluggish cultures can often be revived through gradual feeding and scale-ups.

 

Refeed: Readying your Brew for Battle

If your culture is highly active and quickly forms a healthy pellicle, you can usually jump straight into a full one-gallon brew.

But if the culture seems sluggish or slow to form a pellicle (or doesn’t form one at all), it’s often better to transition it through a smaller fermentation first. Think of it as a new recruit that needs a hot meal, some training, and time to strengthen before being thrown into full battle.

This process is called a refeed.

A refeed simply means providing the kombucha with fresh sweet tea so the culture's food source is replenished. Instead of brewing a full gallon right away, you're gradually scaling up the starter culture in a small container first.

This helps prevent the microbial population from becoming too diluted. The less concentrated the culture is, the more vulnerable it is to infection and weird fermentations.

What You'll Need:

• 12–16oz kombucha starter (whatever you currently have)
• 16oz fresh sweet tea
• 32oz mason jar

Sweet Tea Recipe

• 8oz boiled water
• 2g black tea
• 19g sugar
• 8oz cool water

1. Steep the tea, strain it, and stir in the sugar until fully dissolved. 
2. Add another 8oz of cool water to help bring the temperature down faster.
3. Add the starter to a 32oz jar. You can keep or remove the pellicle here. It doesn’t make functional difference. Before adding the tea to the starter, make sure it’s under 90°F.
4. Then top the jar off with sweet tea, leaving an inch of space from the top.
5. Cover with a cloth and let it ferment for week or so, checking for pellicle growth.

 

Deploying the Culture

If everything goes right, you should now have around 32oz of fresh, active starter culture ready for its first full brew. 

But before embarking on your brewing quest, let’s go down the checklist. Remember standards?

✅ It should have grown a pellicle.
✅ The liquid should taste sour without any off flavors.
✅ There should be no signs of mold.

If this is where you landed, huzzah! You're ready to brew a full gallon. But here’s the cool part: you now also have backup starter.

You only need about 12oz of starter to brew a gallon, so you can leave the rest in the 32oz jar as a little SCOBY hotel. A reserve army waiting in the wings, in case a brewing calamity strikes and you need to start over.

Having backup starter makes brewing a lot less stressful. It also gives you freedom to experiment with different teas, sweeteners, and flavors.

And if you’re looking to experiment with truly advanced brewing technology… like tea that flavors your kombucha… look no further.

 

And now… onto the next adventure:

Ready to make your first gallon? Check out our Batch Brew Guide.

Already brewing with a pellicle? Venture into the Continuous Brew Guide.

Want to learn more about maintaining your reserve army? Visit the SCOBY Hotel.

 

Don't forget the check out the rest of our 📜 sacred brew texts: