Did you see our last video, in which we tasted and talked about the differences, both in terms of production and flavour, between homemade and various commercially produced kombuchas? If not, do click here. We looked at a range of kombuchas: some produced using traditional methods, some that are filtered for shelf stability, others that remove all the sugar and add in sweeteners, and even preparations of concentrated kombucha for dilution, and powder in sachets.
As we went through the process it became abundantly clear that all of these products are called kombucha, but .. are they really? There is no proper definition; an ancient culture from the far east, thousands of years old, handed from person to person, generation to generation, via ancient trade routes, doesn’t really need a definition. Until it lands up in 2024 when it’s become big business. And when big business gets involved, processes tend to change, often to maximise profits, but also for product stability, ease of manufacture and reproducibility, qualities that consumers often demand.
So we devised a test that would identify just how much like real, home made kombucha, our bought samples were. In theory, any batch of kombucha fed some sweet tea should be able to generate its own SCOBY (the microbially- generated cellulose mass that can look like it’s taking over the jar), if it contains the essential building blocks. In real kombucha, the symbiotic community of bacteria and yeasts is recognisable as particular to kombucha and it quite stable, so that batch after batch, real kombucha can be used as back-slop to make more kombucha. And importantly, the kombucha it makes time and time again looks like kombucha, smells like kombucha and tastes like kombucha.
So, the million dollar question is, which of the commercially-produced kombuchas we reviewed in our last episode can be successfully used as back-slop to make more kombucha?And how did Jo’s kombucha perform? Listen to the episode to find out.
All of the kombuchas tested were purchased by us, and products used were simply those that we have had experience of / were in the shops we frequent / had piqued our interest.
TLDL – Too Long Didn’t Listen Summary!
We are looking at what makes a real kombucha - we have concluded a key test is one you can buy and use as a backslop to start a healthy and recognisable kombucha batch at home. Coincidentally the ones that did this are the ones that are produced using straightforward recognisable traditional kombucha-making methods.
We mixed 200 ml of tea with 200 ml of each test kombucha. We left them with cloth covers at room temperature for 29 days, assessing pH and taste at the outset, day 17 and day 29 and visually assessing regularly. Lo Bros joined late, so fermented for 13 days. Nania’s Vineyard joined later, so only had 7 days fermentation time.
A real kombucha should be able to make a fresh batch of genuine and tasty kombucha when used to inoculate (or back-slop) fresh sugar-sweetened tea. The pH should fall as the brew progresses because of the organic acids produced by the kombucha microbial community.
Our theory is that a good quality kombucha will produce a SCOBY; a cellulose mat containing bacteria and yeast (a process often driven by Komagataeibacter bacteria).
We tested Remedy, Equinox, Momo, Cidrani, Pure Earth, Lo Bros (2 flavours), Nania’s Vineyard and Jo’s home-brew.
The only batches that tasted and looked anything like kombucha were Momo and Jo’s home-brew. Nania’s Vineyard joined the experiment late, so had it been given more time, it likely would have come good as there was a nascent scoby forming (see video).
Save for Remedy and Lo Bros, the pH in all the commercial samples (and Jo’s home brew) fell over time. With Remedy, the pH rose between days 1 and 17 and only started dropping after that. With Lo Bros, the pH never fell, it rose.
Remedy, Equinox, Momo, Cidrani and Jo’s home-brew grew some form of SCOBY but only Momo and Jo’s home-brew grew what looked like true vibrantly healthy SCOBYs. Momo produces commercial kombucha using traditional methods, as does Nania’s vineyard which was behind, but had definitely started SCOBY formation.
Equinox, Cidrani, Pure Earth, and Lo Bros all had some form of visible mould growth.
In descending order of kombucha quality based on our criteria:
Momo and Jo’s home-brew (and likely Nania’s vineyard with more time).
Remedy
Equinox
Cidrani Pure Earth and Lo Bros.
Our Kombuchas after incubation
A drop in pH and some sort of growth on top is not sufficient to render something akin to a traditional kombucha.
Kombucha contains a complex community of bacteria and yeast; traditional methods of making it maintain this community. Commercial methods that alter that process to try to better fit a live fermented product into our modern food production and transport systems disrupt this balance.
Research claims that kombucha is anti-diabetic, anti-cancer, anti-inflammatory, anti-hypertensive, anti-hyperchoesterolaemic, anti-obesity, anti-oxidant, immunomodulatory, anti-microbial. There is evidence for all of this in animal and in vitro models but not yet in humans; the research has been done almost exclusively on traditionally made kombucha, where the complex community of bacteria and yeast produce a rich brew of bioactive components, as opposed to modern derivatives. REF 1.
One pilot study of poor standard so far whose findings that it lowers blood glucose in diabetics with poorly controlled blood glucose is not reliable for various study design issues - one of which being they only ended up with about 7 people who did the whole study! But it’s a start. REF 2.
Humans have been drinking traditionally made kombucha for thousands of years, but only drinking modern style kombucha for about 10 minutes. We don’t know whether these altered kombuchas share the same potential health benefits as traditionally made ones.
NB Earlier this year, BBC Good Food did a taste test looking at 30 different Kombucha brands – BUT not only do they say at the top of the article that they get commission when you follow a link ( THANKS JO for noticing that), it’s got nothing at all to do at all with kombucha quality. They should’ve asked us! Below you’ll find a method for working out whether your favourite shop booch is the real thing or not.
How to check whether your favourite kombucha is all it should be:
Take a bottle or can of your chosen booch. Put 250 mls in a large jar like we used in the video. Put a tea bag in 250 ml boiling water with approx 15g sugar ( a heaped tablespoon). Steep for 3-4 minutes, stirring to dissolve the sugar, then fish out the tea bag and leave it to cool. When lukewarm, add to the kombucha you’re testing. Cover with a close-woven cloth or paper towel, fasten with a rubber band and leave for about a month out of direct sunlight at room temperature. Check back and see what you’ve got!
We do love a comment and/or a question. Let us know your favourite kombuchas, and if you’re a home brewer that started yours from a bought bottle, we’d be very interested to know the brand.
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Key references
Kombucha in Diabetics trial PMID: 37588049
Kombucha review by Andrade da Anunciação et al 2024 PMID: 38930509
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