Interview: Caroline Gilmartin & Jo Webster, Fermentation Experts
Edited transcript (original audio at the bottom).
Booch News: I was delighted to make contact with Caroline Gilmartin and Jo Webster, two British fermentation experts who live in the southwest of England. I’d found them on the Substack platform, which some people might be aware of, where they host two videos on kombucha posted to Booch News, which showed the varieties of commercial kombucha out there and their capability to generate new kombucha from what’s called back-slopping into the sweet tea base. We started out by talking about their focus on the followings that they have on the Substack platform, and the conversation continued from there.
Have a listen.
Caroline Gilmartin: I’d like to grow my Substack following, but really, I like Instagram. I like the interaction with people on Instagram. It’s media. There’s always somebody online to talk to or to listen to me going on about fermented foods. I can see the value of Instagram still. But yeah, I think Jo and I have, to some extent, we’ve got a different set of followers. I’ve got lots of mum, have-a-go followers, and Jo’s got a lot more serious. I think you have. I think you’ve got more serious, more nutritionally interested followers than I have.
Jo Webster: Because I am serious…I’m so serious!
CG :I’m not very serious. But I think that you’ve worked in so many health-related fields that you’ve brought more people with you from that.
BN: Well, that’s interesting, because I wonder if you can share some of your background. Caroline, I see you have a PhD already, and I believe that’s in science and biology. I’ve got your book, Fermented Foods, a Practical Guide, which the first two chapters give an excellent overview of everything about the gut microbiome and so on. I really have to read it two or three times to fully understand it, because I’m not a scientist. And, Jo, I think you’re still working on your doctorate. Is that correct?
JW: Yeah. So, Caroline’s got a doctorate in microbiology, and it was one of her comments that finally galvanized me into going on to do mine. So, I’m thoroughly enjoying that.
CG: Mine was 25 years ago.
JW: Actually, I’m totally loving it. It’s just the fact that I’d probably quite like to put my children in the freezer on occasion. I have to get a bit more done, but there we go.
Commercial kombucha
BN: Well, it’s great that you’re both expert on a wide range of fermented foods, and it was really, though, kombucha that brought you to my attention. As I said, you have two videos on sub-stack, and I kind of reviewed them in reverse order. In the one, though, that many people have commented on, you tasted a range of commercial kombuchas and speculated on the production methods they used, and looked at what you call kombucha and no-bucha, and even into things like packets of powdered kombucha…
JW: …and concentrate. So, I think Caroline and I, we’re very different people, but we have a common desire for some level of scientific rigor and transparency in the fermented foods field, because what we can see is what’s been a millennia of human usage and harnessing of microbes has, in a good way, become more common and more well known, and with a greater understanding of the gut microbiome, to the potential benefits of the interactions with microbial metabolites and constituents and the microbes themselves, has led to increasing levels of commercial interest.
But in that process, most of these, whether it’s your milk kefir grains or the kimchi or the kombucha, historically, these were made in communities or in families. There was no transport chain to speak of, there was no refrigeration, there was no issue, but with our modern transport system, the cost of refrigeration to keep live fermented products manageable and not exploding comes cost and issues for large-scale commercial producers.
We felt that in lots of areas, particularly with kombucha, there are things happening that with some level of greenwashing on websites means that people may be thinking they’re buying traditional sort of homemade process kombucha, and that’s not what they’re getting.
We’re not here to get aerated or criticize or, you know, denigrate people for the commercial choices they have made, but we are here to be a voice for transparency and pointing out where things are being said or maybe things are being glossed over in terms of filtering out yeast or pasteurizing or the debate between aluminum cans and glass bottles. So that the people that care, because not everybody does care, might be able to use the information we provide to discern so that they can choose the fermented drinks made the way that they want them based on what’s important for them.
At the moment, there is a parlous lack of clarity for consumers.
Testing commercial kombucha
So that’s what led us to meet up and go, Caroline was like, well, damn it, we make kombucha. The basic tenor is by seeding, by back-slopping from your existing kombucha into your tea to make new kombucha. She’s full of bright ideas and said, why don’t we just do it? Why don’t we just buy a load and see what happens? The results were completely fascinating by our perspective.
CG: The results were so fascinating. We just started today doing it again with another 16 different kombucha because people were interested and asked us, oh, but what about this brand or what about that brand and what about the other brand? And very importantly, what we want people to take away from this next round of doing it is it’s very simple to try this experiment yourself. Whatever kombucha you’re interested in, if you want to see if it will make decent kombucha, take it, add some tea, and see what happens in three or four weeks time.
JW: Yeah, and it’s super interesting from the, you know, we’ve got a list of 16 makes, some bottled, some canned. We’ve actually got Caroline’s homemade one included this time alongside mine, which we didn’t have last time. But it’s been really interesting talking to some of the people in advance. So we ordered all of the kombuchas anonymously, so there was no risk of any sort of cheating or using up there and bought and paid for them all. So there’s no bias. There’s no backhanders happening at all. But it was interesting in talking to some of them.
There was one we were trying to find out who made the M&S one, for example, and M&S is in it. We’ve done it all blinded. We’ve labeled the kilners this time and had a third party put the kombucha in. We don’t know which kombucha is in which kilner jar this time, which I think is really important.
This is just for an example, who makes the M&S one, which actually looks super interesting to me because what it looks like, they’ve got a complex method that they’re developing of taking out the yeast. Of course, the yeast can consume the sugar to produce alcohol, which can be a problem. People don’t want high levels of alcohol in their kombucha. But of course, one of the founders rightly pointed out that we probably won’t be able to grow or make kombucha from that, because if there’s no yeast to ferment the sugars in that process, then that process is fundamentally changed.
Certification
BN: But this all does get back to what you and Caroline, Jo and Caroline, as I do, being homebrew kombucha makers, see when we go to the shops, to the stores, and look for commercial kombucha. As you said, Jo, you can actually put drain water in a bottle and sell it as kombucha because there are no standards. And so, people buy what is named kombucha, and in the shops, it might not bear any resemblance…
CG: …to what we know is kombucha, but again, I don’t know how you deal with that. I know that kimchi is a protected term. What’s that word called when the term of kimchi is protected? You know, there’s like a special process that you go through and you get some kind of certification. So, it’s got a very long name. I can’t remember. [Administered by the National Agricultural Products Quality Management Service] There’s a special process that you can go through that the Korean government can obviously afford to do. But kombucha doesn’t have enough ownership by anybody. So, getting a definition of kombucha is very, very important.
JW: Also, that can be problematic because I know that a whole group of people went through it with sourdough as well. I think there really are pros and cons to that because, you know, like anything, when you start to put rules by something, then you get enforcement. Then unless everyone agrees what the rules are of what the definition is, then you can get small producers being excluded by onerous processes because some third party has decided. So, I think it’s really tricky.
We’re not saying that we know what kombucha is. I think what we know is what there’s been a really long history of consumption of. That is: green or black tea with sugar, with a backslop, that’s acetobacter, gluconacetobacter, and komagataeibactor, and some yeast in there doing their thing to create a slightly acidic drink that we know has those live microbes in there and a range of gluconic acid, glucuronic acid the other sorts of organic acids.
CG: What is very interesting to me is this trend to pasteurize this and to filter and to remove all live microbes and to put in something that is designated a probiotic
JW: So, we can go back and we can see what’s been historically made for a long time and the method that it was made by. But then there’s still not all that much research really on that traditional method, let alone on the method that all people have been making. We know nothing about what happens if we filter out the yeast or if we add this in or that in.
CG: And if you pasteurize it, whether you’re going to actually denature a lot of the compounds that are really good for you anyway. We don’t know enough about this stuff. I find it interesting that all of these bottles and cans in front of us now. There’s another issue as well, whether it’s being cans or bottles, have, you know, they’re gut-loving drinks.
Well, is it a gut-loving drink? There’s so many terms being used on so many of the websites in the cans that probably do breach trading standards. There’s a lot of that. I think we can all claim transparency. So if you do care about kombucha, you’d have more of an idea that it was a properly originally made kombucha…
JW: …and if you care about that, if you care about that or if you don’t. This is a really interesting thing that someone said to me, I listen to your podcast, what should kombucha taste like? And do you know what? Not many things shut me up. But that did shut me up. Holy mackerel, if you’re not making it at home, if you’ve never tried home kombucha, most people drinking this don’t know what it’s what home normal traditional kombucha smells like or tastes like to even be able to compare these commercially produced ones.
CG: Some of the commercially produced ones just taste like pop. If you had ginger beer that my dad would give to my children. Or if you have for, you know, one of these fiery ginger kombuchas, you would not really be able to tell the difference. There’s no real defining feature — that tang or that kind of even slightly cidery taste that you get from the kombucha.
JW: But then how do people even discern if they don’t even know? But then, you know, the fact is we’re not here to beat people up about it. I think a lot of people don’t care about the difference between traditional and these modern kombuchas. But I think a lot of people may be buying these things thinking that they’re good for them.
That’s where we feel like there should be a bit more transparency ideally with commercial producers about what they’re saying on the website, what they’re saying on the can and transparency about the process. Not that there’s a right or wrong process, but inevitably, the more process there is.
CG: People are always going to muck about with stuff. It’s in human nature. I think the issue is that any research that has been done on kombucha–and let’s just say there is precious little that–that has been done with proper, traditionally brewed, kombucha. That has not been done with kombucha soda with CBD in it that’s filtered with a backslop of bacillus coagulans added. So I would love somebody to do some proper research on this. I really would. They don’t need to. There’s no research that needs to go on in this area because it is an enormous market.
JW: What I did find is that I started drinking one brand. The other thing these things are great for is more choice for drinking less alcohol. So on a Friday night, I would be partial to a sedating gin and tonic, to be fair. Now, I’ve been having my water kefir that I make or my kombucha. But my husband had been buying a few makes from the supermarket. And I found myself, I really like this make, but I found myself slightly hankering after it. Then when I looked, I was like, I’m not used to drinking sugar, sweet and fizzy drinks to that extent. I think there was just something in the make of that drink that was slightly habit forming for me. That is a bit caution-making from my perspective.
Scientific research
BN: Well, I’ve got a question for you both. You’ve got science backgrounds. And I’m wondering, what’s the chance for valid scientific organizations to duplicate, replicate the research you’ve done in your kitchen and publish studies on, you know, the effectiveness of different kinds of kombucha on consumers?
JC: I mean, in humans, you’re talking a huge amount of money and an inordinately complex playing field because of the amount of variables. Like, it’s quite hard to bring humans in. You know, humans lie when they are studied. Keep other variables normal in order to be able to then just add in the kombucha.
CG: You’re only having, say, 250 mils, aren’t you?
JW: There are studies in the pipeline I know of through various decent scientific establishments. But generally, they’re looking at they’re looking at fermented foods and drinks collectively, as in an intake in humans of a combination of those items. There’s so many layers that need to be done on kombucha. One defining in detail actually what’s going on in kombucha that’s traditionally made and then in the kombuchas that are made these other ways. Then there’s a whole other level of adding it into humans.
Also, the research into testing feces, that’s inordinately unreliable.
CG: But also, the fact is that no two kombucha SCOBYs are the same. You might have a kombucha SCOBY that’s got saccharomyces boulardii in, which is a known probiotic. It might be absent. You might have a kombucha SCOBY that’s got lactobacillus.
JW: But you could control and then post-test for that. But the answer to the question is there has to be somebody who cares enough about the outcome to put the finances and the people in what is hundreds of thousands of pounds of money and also work in order to clarify this. Manifestly, part of the question is how much do people actually care? How much do people care?
CG: People don’t need to do that now, because we’ve got 15 different varieties of kombucha in front of us today. And it shows there is a really happy, healthy kombucha market. Yeah. In the States, I believe is absolutely enormous. So we’re already possible where people need to prove anything.
JW: Also, it becomes completely ironic to me because we’re all banging on about ultra-processed foods. We’re fretting about how much aluminum might be in our cans of kombucha. But actually, if we’re actually really worried about health, I read a really interesting thing that was like, if a fundamental pillar of your life is corroding in terms of stress, connection to other humans, sleep, and basic fundamental nutrition, the things you’re eating three, four, five times a day, you ain’t going to fix that with a can or a thing of kombucha.
So in some ways, yes, whilst in theory, we’d love this research to be done, actually, what would happen? Would it change behavior? Would something come out of those findings? That would improve people’s health or change their behavior.
Standards bodies
BN: So as a follow-on question to that, absent the expensive scientific research, is there any chance organizations like the Good Housekeeping Seal of Approval or Which? magazine would be able to publish publish reviews and become a standard for the industry, in the beverage industry, that could assist consumers in kombucha to know what’s out there?
JW: It’s a super interesting question. And interestingly, very recently in the UK, the Fermenters Guild has been set up, I think it’s two years old now, which has been a fantastic bringing together of Fermenters. As you can imagine, both Caroline and my motivation for the Guild on some level of, not by a stick, but by carrot, holding out of standards and knowledge sharing around what, you know, authentic, what we’d understand to be the process of a range of ferments, maybe not just kombucha.
But the truth is, even within a collection of fermenters, there’s different motivations and desires and there’s different priorities. To some extent, that isn’t the sole direction the Guild has gone in, it would be fair to say. It is difficult to have those standards, to have a Which? magazine for ferments. One would need to know to have agreed amongst professionals or experienced people in that field what those standards are to then have objective criteria to be comparing things against.
CG: And professionals in the field absolutely cannot…
JW: Well, I mean, I tried to get a think tank together last year, unfortunately, because someone in my family became very ill. A think tank together to bring knowledge sharers, scientists and commercial producers together. I haven’t restarted [that project]. In theory, it would…
CG: It won’t work, because actually the range of methods of production are so vast. There are so many things that you can do. There are so many ways that you can tamper with it and so many ways that you can justify it. And again, if you are looking at running a business to make kombucha available to people, we understand it is really, really difficult. I’d just like to see a lot more transparency so that people really understood. I think it’s very difficult to find out the processes behind what’s in these cans and it would be much better if people..
Health claims
JW: But if there’s no, you know, I don’t know what it’s like in the US but in terms of, you know, health claims, inappropriate health claims. In the end, Caroline this afternoon was just like, ‘I’m sick of this!’ Because we’re just going through website after website with just unsubstantiated claims being made all over the place in terms of gut health, et cetera. But if there isn’t the money in, you know, health claims standards or whatever to be able to go through websites to police this.
Ultimately, it was a funny thing when I was trying to set up this, I think, that last year. I said to one of the commercial producers, you know, we want people to know what the traditional method is. This commercial producer said, yeah, but people don’t care. I think that person might be right. That there’s only a small percentage of people possibly that care. Probably those are the people making it traditionally because it’s such piggin’ hard work to do that. Even today with these 16 brands, the person setting up the experiment for us, we could hear exclamations from the other room where a bottle has been opened and then it’s exploded everywhere. That’s probably from the traditionally produced ones.
CG: If you’re going to sell traditional kombucha, you have to sell it to a responsible audience because if you sell that bottle of kombucha to somebody who isn’t listening or paying attention, and understand when they take it home that they’ve got to keep it in the fridge and they just put it on the side in the kitchen and you get an explosion on your hands, you are out of business.
So we totally understand the complexity of this. I’m always going to be somebody that encourages people to make their own kombucha.
JW: It’s a no-brainer, isn’t it? It’s easy and it’s deep and it’s fun and it connects people.
CG: I do believe that there’s some kind of terroir thing going on with your own kombucha whereby when your kombucha has been in your house for a little while, you will prefer it to any other kombucha out there because the microbes in your home and in your environment will be inveigled into your kombucha and I can tell my kombucha out of the ones that we are going to test.
JW: Yeah, we’ll have to see because Caroline thought she could. Well, first of all, she came in and said she’d done a urine sample for us! I’m hoping that it wasn’t actually her urine that we’re now making.
Market potential
BN: Well, obviously, there’s a lot of developments here. You asked me about the US and I’ve put pictures on Booch News showing the vast array of kombucha available in most of the markets here, but even here and especially in the UK, we’re at a very early stage in the development of the market. When I was back in Britain last month, I saw how infinitesimally available it was and, you know, maybe it’s like the market for yogurt 30 years ago when there was hardly any available and now it fills the shelves. So, do either of you see the potential for growth in the market coming anytime soon? And will there be an increase in the number of us home brewing?
JW: I don’t know. One would hope so. To me, there’s so much structurally wrong with our society that most people haven’t got the time to do basic cooking and, you know, they’re building flats and houses without kitchens now. So, in an ideal world, obviously, that’s what we would love to see happening.
CG: I shall carry on trying to do my absolute utmost to persuade people that there is a great deal of value in doing very simple things to empower yourself to look after yourself and your family.
JW: But to me, that isn’t just about consuming the kombucha either. For me, having some fermented foods and drinks in our lives is about nature connection and a constant reminder of our place in this enormous and complex fabric of life.
CG: I’m far too practical for that.
JW: Can you not ever think about the magic of what is happening in that?
CG: Well, I do think about my addiction to my own personal kombucha because it’s my own personal microbes and, you know, I do feel very connected to that and my milk kerfir.
JW: I think all I’m saying is that I’d really hope that that happens, Ian, but I think there definitely also needs to be room for commercial brands where people don’t have time and never will get round to that.
Consumer choice
BN: Yeah, so it’s just like with yogurt, right? You can go to the supermarket and get a container filled with pink goop and sugar and it’s sold as raspberry yogurt, but there’s also the choice for natural yogurts that are clearly marked. What does that tell us, if anything, about consumers’ choices and the availability of the natural versus the artificial?
JW: So unless we start to be more discerning and look out for this information, if we believe the green wash and the stuff on half the things that we’re buying, then we’re going to end up probably eating things that we don’t actually intend to eat. The truth is, in 20, 30, 40 years’ time, it’s only us that are going to be living with the consequences of those choices, not the people making these products.
CG: I would think that, I mean, from my perspective, it would be absolutely lovely if at some point in the future, in the world, people could drink a can of kombucha. It would be a fantastic way of being able to improve the health of the nation if we sold kombucha that was known to have a glucuronic acid and acetic acid content that was of benefit to you and a range of microbes naturally occurring, working together, that would be good for you.
So it would be an absolutely brilliant way of improving the health of the nation if indeed that worked. But that is never going to be a priority. Improving health of the nation is literally on the bottom.
JW: Well, it’s definitely below making money, isn’t it?
CG: It’s definitely below making money. No, it’s literally at the bottom because making money is so easy.
Non-alcohol alternative
JW: Also, to be fair, even if we never have all of that information and we chose to drink some of these kombuchas instead of, you know, we swapped out half of our alcohol consumption a week with this, we’re probably going to be better off. Even without having shown them this amazing benefit. And that’s a whole other conversation is, you know, are there many actually probiotic species in kombucha?
I think our idea of probiotics is going to change because historically, the research in that has certainly been in milk-based and dairy-based microbes, and that’s going to open out significantly in years to come, too.
CG: I have to say, I am a non-drinker, and I haven’t drunk since over 20 years now. I’ve never liked it. So my perspective is, I totally get this idea that drinking any kombucha is probably going to be better to lower your alcohol consumption, which is why we are just about transparency for people who really care about it, not being obsessive about people not wanting to use it to make kombucha. Because if you’re out and about on the run, it’s better that you grab yourself a kombucha than a tequila mixer.
JW: The thing is, we don’t want to become so puritanical that people are confused and then don’t buy kombucha at all and go to the gin instead.
CG: It’s just all about understanding what it’s about. And obviously, we’re going to do everything we can to make sure that people do understand that kombucha exists on different levels. Have a go at making it yourself. Have a go at trying a real thing.
JW: So just remembering that any of us are free to take the kombucha [you buy in the store] and make a cup of tea. We do one liter with two tea bags, 50 grams of sugar, and make your tea, put the kombucha into it and see what happens.
CG: But also, we’ve got a couple of UK brands that are making what I would call real kombucha using a traditional method. They’re partnering with really quite large scale restaurants. So you can get Momo in Gailes Bakery and you can get the L.A. Brewery one in Nando’s, for heaven’s sake.
There are instances out there where companies are trying their absolute best to keep to the traditional methods. So it’s a slight feeling of mine that if some people can do it, everybody could do it if they wanted to.
JW: I guess what you’re saying is if your principles and your priorities are for the kombucha to be as close to the traditionally made as possible, there are ways and means of doing so.
Cans vs. Bottles
JW: I was very interested in the can/bottle dilemma. I know the gentleman at Go Kombucha has written quite a lot about this. I had a look at quite a few of the papers. I think what’s really interesting to me is one, if we just focus on one risk factor for humans, we might be lose sight of, you know, we can worry about the level of aluminum in the can. But if we’re destroying the environment by mining silica and transporting very heavy glass backwards and forwards, and that’s contributing to climate change, then, you know, to me, we need to look at all these factors in the round rather than focusing in, in nuanced detail in one area.
Also, in terms of aluminum, there’s aluminum in a lot of foods, there’s aluminum in antacids, actually. So if anyone’s on Gaviscon, they’ll be taking about 95 milligrams of aluminum hydroxide in in their five mill of Gaviscon. And there’s aluminum in breast milk and infant formula as well. And the levels of tolerable daily intake is about one milligram per kilogram of body weight, but our bodies are actually really good at clearing it. So we more than 95% is cleared by our body successfully.
BN: If I can just say Gary at Go–Gary Leigh—also has the concern that the cans are actually lined in plastic and that is also leaching into the kombucha. Whereas that sold, as he does, in glass bottles is in an inert package so that even though the linings in the cans are now meant to be BPA free, his issue is also that the plastics are leaching into the acidic liquid.
JW: I think he and I are agreed from what I’ve read of what he says. I would be really keen and it comes back to the same thing to actually be have cans of kombucha tested for how the linings perform and what happens there because that hasn’t been done yet. The one that we looked at was an interesting study in terms of looking at Green Cola and acetic acid solution and then another there was another liquid in there as well, Red Bull.
But I think the truth is, there’s microplastics everywhere, you know, when they look in organs of postmortems to find microplastics in almost every organ in our body. So, I think for me, it’s about, yes, this is a risk factor, but so is transporting large amounts heavy glass all over the place in environmental impact. I’d love for someone again, who’s going to do it to actually do this research in kombucha, which as we know, as Gary points out is important.
In front of us, we’ve these 16 [brands we are testing] in both cans and bottles. Clearly there are also companies that are doing both cans and bottles. So they’re doing ambient in cans and then they continue to do traditional in bottles.
So ideally, we want to take a curious perspective on it and actually interrogate this. Ideally, someone would actually do some research into it. But remembering that there’s other factors at play. So just panicking about plastic linings. If you’re drinking liters of the stuff, then maybe this is going to be an issue. Actually, in the scale of issues we face, nutritionally and environmentally.
CG: It’s just another food that you know, you really would do very, very hard to avoid it. And again, you’ve still got this idea of people thinking that glass is necessarily better. But as we know, the weight of the glass bottle, the production, the heat required to make a glass bottle, the mining of the sand. The recyclability. It goes into making a glass bottle. Again, I think the jury’s still out
JW: There are some companies that are great at trying to do offers on their websites to get the bottles returned so that they can be reused.
Kombucha on tap
BN: And actually, it points to the most environmentally friendly way of consuming kombucha apart from home brewing is when you can get kombucha on tap. And it might help if more British pubs started offering it on tap to people who want a non-alcoholic alternative, since I understand hundreds of pubs in the UK are closing every month.
CG: Our local round the corner to us, they’re all closing.
JW: And also, I’ll go into ones, and I know I’m in my little echo chamber, but, and ask, say, do you have kombucha? And honestly, I haven’t been into a pub that’s actually stocked kombucha or water kefir.
CG: A large supermarket in Minehead in the UK, which is a small town in the north of Somerset, there is not one single brand of kombucha in the shop in any way, shape or form.
JW: It’s not something that they have or know about. And that’s a sad thing as well, but it’s sort of niche middle class.
BN: Yeah, that’s very true. Although I think in certain areas in the US, like where I live in Vallejo, which is an old shipbuilding town, there’s a lot of kombucha in the local supermarket that gets drunk by people who are not middle class, but, you know, lower middle class, working class, and definitely not the young yoginis that you see often on the Instagram for the kombucha companies. Anyway, thanks so much for spending time talking with us and sharing all this information on Booch News. I must say before we sign off, that if people want to contact you, Caroline, you’re on Instagram at every.good.thing. And Jo, I think you’re on Instagram as jo.webster.health. And from there, people can click through to your sub-stack and various other places where they can find your material. It’s been great talking with you and look forward to this test you’re doing with another 16 brands.
JW: Thanks for speaking with us.
CG: Yes, it’s been great, thank you.
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