Fermentation Education: Kombucha & Jun tea

Although it’s been over a month since I brewed the last batches of kombucha and Jun tea, my SCOBYs are still going strong, growing slowly in their jars, emitting wafts of sour mead and waiting for the day I will feed them again. If all this sounds a bit like crazy talk to you, allow me to take you on a brief foray into the world of fermented tea. 

Kombucha & Jun tea:

Kombucha is a type of fermented tea made using sugared tea and a SCOBY: a symbiotic colony of bacteria and yeast. This colony lives in a little house made of cellulose, which looks a bit like a jellyfish. The SCOBY eats tea and sugar and turns it into acetic acid and a little carbon dioxide: in other words, it turns your sugary tea into a refreshingly sour, lightly sparkling beverage.

How does it work?

One good thing to know about SCOBYs is that they keep on growing. Every time you brew a new batch, a new layer of SCOBY will form at the surface of your tea. If you know someone who makes kombucha, they will happily give you one of theirs and as soon as you’re brewing yourself, you’ll soon be wondering what to do with them. At which point you can start giving them away to other budding brewers. And so the cycle continues.


Baby SCOBYs in small jars.

I walked away from my fermentation course with two tiny pieces of SCOBY, cut off from two large ones our teacher brought with him to class. One of them was accustomed to black tea and sugar – a classic, basic kombucha in other words, while the other – Jun – preferred a diet of green tea and honey. Placed in little jars along with their drink of choice and a bit of vinegar, they soon grew into sizeable jelly-like discs. At this point, you’re ready to start brewing.

After a week or two – or even a little less – the SCOBY has transformed sugar and tea into a refreshing, probiotic soft drink with a hint of fizz. Make sure to sample the kombucha every once in a while to see how the flavours are developing. The longer it ferments the more the sugar will be converted to acid. Ferment for too long and you’ll end up with something that tastes like straight up vinegar, ferment too short and it’ll just be slightly funky, sugary tea. Regular sampling will enable you to pinpoint that sweet spot where all the flavours are in perfect harmony. You can either drink it straight out of the jar, or bottle the kombucha with some flavourings of your choice  – raw, organic ginger is great – for a secondary fermentation and even more bubbles.


Basic safety rules:

  • Hygiëne: make sure jars and hands are scrupulously clean.
  • Use strong tea, but let it cool down to room temperature before introducing the SCOBY.
  • Use 75 – 100g of sugar or honey per litre of tea (more sugar is more acid), and 4 tbsp of kombucha from a previous brew or 2 tbsp vinegar.
  • Ferment out of direct sunlight
  • For primary fermentation, cover the jar with something breathable, like a paper towel or a piece of cheesecloth, and cover it well: you don’t want any insects in there!
  • For secondary fermentation, use plastic bottles or glass bottles that can withstand pressure, like old beer bottles with swing tops.
  • Worried about the way your SCOBY looks? Truth is, SCOBYs  generally look weird and a bit off-putting. They come in many shapes and sizes, some smooth, some knobbly, some light, some dark, but as long as they don’t have black spots or white fuzzy patches of mold, they’re absolutely fine. If they do, however, your SCOBY is sick or dying and should be discarded.



Welcome to Cuisine d’Eli. My name is Elizabeth and I’m a personal chef, writer and photographer with a passion for sustainable food. I’m based in Utrecht, the Netherlands. Contact me for more information and/or bookings.


Welkom bij Cuisine d’Eli. Ik ben Elizabeth: duurzame kok aan huis, schijver en fotograaf. Meer weten? Neem gerust een kijkje op de rest van mijn website of neem contact met me op voor meer informatie.

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