Can You Use a 1-Gallon SCOBY to Make a Half-Gallon Batch of Kombucha?

We often get asked: “Can I use a SCOBY that’s portioned for a gallon to make just a half-gallon of kombucha?” The short answer is: yes, absolutely.

Using a One-Gallon SCOBY for a Half-Gallon Batch

A SCOBY and starter tea designed for a one-gallon batch can definitely be used to make a half-gallon batch. Just don’t scale up. If you’re looking to make a larger batch, head over here: Kombucha Ratios and Scaling a Batch Up. Otherwise, you’ve got two options:

Option 1. Split it in half

Option 2. Use the whole thing

Option 1:
Split the SCOBY and Starter Tea

If you prefer to use only half the SCOBY, just divide both the SCOBY and the liquid starter tea evenly. You can cut the SCOBY pellicle in half—don’t worry about harming it. The disk itself is a non-living structure made of cellulose; the real life is in the microscopic bacteria and yeast that live in the structure and throughout the liquid tea.

Once you’ve split the batch, here’s how to store the unused half:

Use a glass container (a mason jar works well)
Cover it with a breathable cloth, like muslin or a coffee filter
Secure the cover with a rubber band
Keep it at room temperature

You can use this reserved portion to start a new half-gallon batch whenever you’re ready. Just follow the instructions here: How to Make Kombucha

Option 2: Use the Whole SCOBY

This method is simple: just use the full SCOBY and all the starter tea in your half-gallon batch. It’ll work perfectly fine—the only difference is that your brew will be more acidic or tart starting out. This isn’t necessarily an issue with fermentation; it’s more a quality consideration, as when using the proper amount, the acidity develops as the fermentation progresses. By adding the additional starter tea, sure, you will be adding more microbes, but along with this, the additional starter tea in the batch will give it a head start in terms of acidity.

So, if you prefer the sweeter side, you wouldn’t want to add a jump start of acidification—rather, have it build during fermentation. So again, just something to consider from a finished quality perspective. But to be frank, I would suspect a lot of brewers wouldn’t notice much of a difference.

Bottom Line

There’s no wrong answer here. Whether you go with the full SCOBY or split it in half, both methods will work just fine. It’s all about your brewing preferences and how much kombucha you want to make.

Thinking About Flavoring Your Kombucha?

Once you’ve got your batch going, it’s a good time to start thinking about flavoring. Whether you like it fruity, spicy, or something in between, we’ve got a full section with ideas and tips to help you figure out what you might like.

Browse Kombucha Flavoring Ideas →