"Can I make my kombucha with sweetener instead?" It's one of the questions we're asked most. It's a fair question, especially if you're cutting down on sugar. But the short answer is no: kombucha needs real sugar to brew. Here's why.
The sugar isn't for you, it's for your SCOBY
Your SCOBY is a living culture of bacteria and yeast. The sugar in your sweet tea is its food. Without it, there's nothing for the culture to live on, and nothing to turn your tea into kombucha.
Brewing happens in two stages:
- The yeasts go first. They break the sugar down and ferment it, making a little alcohol and the carbon dioxide that gives kombucha its fizz.
- Then the bacteria take over. They feed on what the yeasts have made and turn it into the organic acids that give kombucha its tangy, sour taste.
That acidity matters. As the brew becomes more acidic, it becomes a place where mould struggles to grow. That's what protects your brew while it ferments.
Why sweeteners don't work
Sweeteners such as aspartame, sucralose, saccharin and stevia taste sweet to us, but they aren't sugars your culture can eat. The yeasts can't ferment them, so:
- your SCOBY goes hungry and weakens
- the brew doesn't become acidic
- without that acidity, there's nothing to keep mould away
Many sweeteners also contain other additives that aren't friendly to your culture. A sweetener brew might look like sweet tea, but it will never become kombucha.
Want a sweeter drink? Once your kombucha has finished brewing and you've taken out your SCOBY, you can add a sweetener to flavour it, as it's no longer feeding your culture. Personally, we think it sort of defeats the purpose, but it's your kombucha!
What about honey, maple syrup or coconut sugar?
Honey has natural antimicrobial properties, so it can behave unpredictably with a standard kombucha SCOBY. It's what Jun cultures are brewed with, and they're adapted to it. If you love the idea of a honey brew, try our Jun culture and our Jun brewing guide.
Maple syrup, coconut sugar and other alternatives can work, but we don't recommend them, especially for beginners. They're very mineralised, and kombucha doesn't really like minerals. They also give a caramel taste that doesn't really go with kombucha's sourness.
As a rule, the whiter the sugar, the cleaner and crisper the taste. White granulated or organic cane sugar gives the most reliable brew. For more on choosing a sugar, see our guide to sugars in fermentation.
What happens if there isn't enough sugar?
Use 80–100g of sugar per litre of sweet tea, and never less than 80g. If the sugar level is too low, the ferment will stall. You generally end up with a sweeter brew, not a less sweet one, because the sugar hasn't gone anywhere: the culture hasn't been able to use it. A stalled brew also doesn't become acidic enough to protect itself, which can lead to mould.
So if you're trying to cut down on sugar, don't use less in the brew. Brew for longer instead (see below).
How to reduce the sugar content
Time is the best way. Most of the sugar you put in doesn't end up in your glass. Your SCOBY eats it as it brews, which is why finished kombucha tastes so much less sweet than the tea you started with. So if you want less sugar, leave your brew for longer. The longer it brews, the more sugar your SCOBY uses up, and the less sweet and more sour your kombucha becomes.
Taste it each day and bottle it when you're happy with the balance. If it gets too sour for you, you can always use it as kombucha vinegar, or bottle a little sooner next time.
If you're diabetic or taking regular medication, check with your doctor before drinking kombucha.
The bottom line
- Sugar is food for your SCOBY, not sweetness for you.
- Sweeteners can't be fermented, so they leave your culture hungry and your brew unprotected.
- Stick to white or organic cane sugar, 80–100g per litre.
- Most of the sugar is used up by the time your kombucha is ready. Want less? Leave it to brew for longer.
Ready to brew? Find everything you need in our kombucha SCOBYs, kombucha kits and brewing sugars.
Got a question about your brew? Take a look at our brewing guides, or get in touch.