The Secrets of Kombucha.

We asked Stacey Wilson to talk to us about Kombucha. There are a whole host of articles and tutorials on kombucha, claiming all sorts of health properties. Stacey talks to us about the practical use and the science of this mysterious beverage.

So, tell me about Kombucha. We’ve seen it on the supermarket shelves and know people who brew it at home. What is it and what does it taste like?

Hi, So basically Kombucha is a naturally fermented fizzy drink. It tastes a little bit like ginger beer and a little bit like apple cider vinegar when it’s unflavoured, but it can be jazzed up with all sorts of other flavours, like berries and fruits, or spices and herbs. Although it’s fermented, it is naturally very low in alcohol (below 1%), and is lower in sugar than your standard flavoured fizzy drinks. It’s pretty delicious!


Kombucha brewing


How easy is it to get started brewing it? What do I need?

It’s super easy to brew at home, and it is WAY more economical to make your own than it is to buy the gorgeous looking little bottles at the supermarket.

To get started, you’ll need a SCOBY, which is the kombucha mother or starter. SCOBY stands for Symbiotic Colony Of Bacteria and Yeasts, which just means that the SCOBY is a mix of yeasts (to give the fizz), and acid-forming bacteria (to eat up the alcohol and produce the flavour).

One of those bacteria also produces cellulose, which is a rubbery sort of stuff, so the SCOBY is a rubbery disc of thick jelly-like stuff which forms on the surface of each brew. If you know someone who brews kombucha they’ll be more than happy to share a SCOBY with you!

If you don’t know anyone who brews kombucha, you can grow a SCOBY yourself from a supermarket-bought kombucha, so long as it hasn’t been pasteurised and the bottle states that it contains live cultures.

Once you have your SCOBY, you’ll need a large glass brewing vessel, some tea, some white sugar, and some bottles. That’s it!

There are recipes everywhere online, but I do give away a cute printable one when people subscribe to my semi-monthly newsletter. Go to for the sign-up link!



People talk about the health benefits of kombucha, about how it’s a great probiotic or a good detoxifier. Is there any substance to those claims? Any proof or is it just marketing puffery and wishful thinking?

This was the question I had when I started writing my second book Simply Kombucha. I knew for myself that the switch to a home-made, natural drink that was ‘living’ had been a positive thing for my own health, but I had no way to evaluate whether that had been a part of wider switch to more natural foods with fewer additives and preservatives, or even if it was the placebo effect.  I needed to find out more.

When I first started seriously looking into it I began with google, as you do, and it was a bit disheartening, really. I found lots of health claims – you know the sort – kombucha would cure hair-loss, it would cure AIDS, it would help with wound healing, and cure cancer – but none of them cited any published scientific research, and many of them turned out to be identical claims – obviously just copied and pasted from one site to another with no way to verify them. I was starting to lose hope that any of it was true.

After a couple of days of this, it occurred to me to look up the scientific research itself – to go straight to the science databases and see if anyone had published research on kombucha. I have an MSc in Biochemistry and worked for a few years in a research lab, so it shouldn’t really have taken me two days to think of it! But in my defence it had been over a decade since I’d been in a lab, and I was a bit rusty.

Anyway, what I found was there there is credible research into kombucha. It is still in the fairly early stages, and definitely not at the curing AIDS and cancer level, but the research clearly indicates that kombucha is good for two things: It is a probiotic, and it is an excellent antioxidant.

A probiotic is a food which contains live microbes that are good for you, and especially good for your gut. Kombucha, being a naturally fermented food, contains live microbes which will make their way to your gut if you drink it regularly. It’s not the best probiotic out there – if you’re looking for a probiotic I’d choose milk kefir or sauerkraut over kombucha, because they have a better range of probiotics, but it does contain some, and it’s a good starting point for people who haven’t developed a taste for lacto-fermented foods.

Where kombucha really shines, though, is as an antioxidant.

Antioxidants are the body’s defence against free radicals. I made a cute infographic for my blog, which I’ll include here which explains the role of antioxidants in the body.

Basically, in a perfect world and in perfect health, your body would have enough antioxidants from the food you eat and from what your body produces itself, to neutralize any free radicals that you come across. Your own body makes free radicals as part of its normal functioning, and we have good mechanisms for dealing with them. BUT we don’t live in a perfect world and few of us are functioning at peak health. We come across more free radicals in our lives than we can naturally deal with, and this can lead to Oxidative Stress. In different people and different circumstances oxidative stress can lead to various disease states including heart problems, general fatigue and immune issues, and cancer.

A good, regular dose of antioxidants can help neutralise those free radicals and prevent oxidative stress, reducing the chances of those diseases getting a foothold.

Some of the research I found demonstrated clearly that, in animals at least, drinking the equivalent of a small glass of kombucha daily helped prevent physical damage from exposure to chemical free radicals. Other research showed that it provided protection against various viral infections. And another paper showed that daily kombucha drinking provided protection against heart attacks.

None of this research was done in humans, I should say. But the signs are certainly good enough for me to be drinking kombucha on the regular!


Any risks?

Well, the vast majority of people will be able to drink as much kombucha as they want, whenever they want.

But every so often you’ll see an article doing the rounds talking about how kombucha is not actually that great for you, and that how people have DIED from drinking it. For the most part these articles are taking what is, for me, an overly cautious approach to kombucha and in some cases are simply scare-mongering for clicks.

I took a good look at the research papers which do investigate those claims of poor health outcomes and, yes sadly, deaths. It turns out that more than half of the reported deaths are because someone is unexpectedly highly allergic to kombucha. So if you have a history of allergy to yeasts or moulds or penicillin for instance, then take a cautious approach to drinking kombucha – start small and really notice how your body responds.

The other causes of negative reactions fell into two categories. One was due to contamination of the brew, either by heavy metals from brewing it in a non-glass container (metals can leach out of ceramic containers because kombucha is so acidic), or from a contaminating microbe getting into the brew, such as Candida. If you suspect that your brew is not quite behaving as it should, you can start again by growing a new SCOBY from a shop-bought brew, which will be about as healthy and predictable as you can get with natural ferments.

The other cause of death was from random and sudden liver failure in some people. This was a vanishingly small number of people, but still obviously significant for these individuals. It seems that for some people, drinking a lot of antioxidants has a paradoxically toxic effect on the liver – you can have too much of a good thing. There was a similar case in the news a couple of years ago of a young woman who had liver failure after drinking a lot of Matcha Green Tea.

Two other types of negative reaction to kombucha deserve a mention as well. One is that some people are sensitive to histamines – a molecule that your body produces as part of its allergic response to something. Histamines are high in all fermented foods, including kombucha, so people who are sensitive to histamines usually can’t drink a lot of kombucha.

The other negative reaction is sometimes called a Herxheimer reaction. It’s when you suddenly start eating or drinking something that has a significant impact on the microbes living in your gut. Antibiotics are the usual culprits but it can also happen with any new probiotic food and it can take from a few days to a couple of weeks to completely settle down. Symptoms can include flu-like symptoms, headaches, nausea etc. If it is the Herxheimer reaction, the symptoms will fade with time. If they don’t, then you may be looking at a more permanent intolerance to something in your kombucha brew.

But it’s worth repeating again that for the vast majority of people, the usual recommended therapeutic dose of half a cup of kombucha per day will pose no problems at all, and for most people it can be drunk freely as much as you like.



What about for children or during pregnancy? It contains alcohol, right?

It does contain alcohol, yes, and because each SCOBY is different and each person’s kitchen environment is different, it’s possible that an individual brew might get quite boozy. This is not normal, though, and for the vast majority of kombucha brews the alcohol level will be well below 1%. Whether that is low enough for your own comfort levels is up to your own judgement.

As far as being good for kids, I’d say that kombucha is definitely better than juice or soda, but it does still have about 8% sugar in it after a week’s brewing, so is still pretty high in sugar. It’s also very acidic, so is not the best for teeth. If you’re looking for a good probiotic for little children, milk kefir or sauerkraut are better choices because of the lower sugar levels.

In our house we try and limit the kids to drinking one glass of kombucha, and drink it with meals to reduce the impact on their teeth. Another option would be to dilute it with ice or water.



What’s your favourite thing to do with kombucha? OR Any great recipes to share?

My favourite flavour way to drink kombucha is to add about a tablespoon of grated raw ginger to the normal recipe and then brew it. It tastes a lot like ginger ale. It also makes a great base for a fruity summer punch.

You can do more than just drink kombucha, though!

Every other Saturday at our house is Pizza night, and we make our own sourdough pizza dough using kombucha as a liquid sourdough starter. I give the recipe for that one away through my website, but the short version is that you take your favourite plain dough recipe, replace the liquid component with kombucha, and leave out the yeast and sugar. It can take a few days to rise, depending on how active your brew is and how warm your kitchen is, but once you’ve got your timing sorted it’s magic. It’s far and away the best sourdough pizza base that I’ve ever eaten.

For more in depth information about the research behind kombucha, and for other cool recipes – like how to use a kombucha SCOBY to make yoghurt, head to And while you’re there, sign up for Stacey’s semi-monthly newsletter for more hints, tips and giveaways about kombucha!



Stacey Wilson lives in Dunedin with her husband, four children, three hens, and a lop-eared bunny called Flicka. She’s a Playcentre mum and a kombucha enthusiast from way back. She runs the website and is the author of two books about kombucha – Simply Kombucha, and Simple Kombucha Sourdough – available at your favourite online retailers as ebooks and paperbacks.

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