In Good Taste #67: A conversation with vinegar expert Dr Caroline Gilmartin
An intro to making your own sour stuff; thoughts on Jerusalem artichokes; Bronte country and Dennis Severs' House
Well, hello there! How are you?
Good I hope. I’m sorry this edition is late. I totally forgot to push “send” yesterday. Apologies…
(Not up for the chitchat? Completely get it. Click the email title to go to a web-based version then jump straight to the vinegar chat or Cultural Fun.)
I’ve spent some time time week getting ferments underway for my supper club at the Lacy Nook on November 27th. Kimchi, obviously for the devilled eggs. Also a spiced ruby kraut that’s going to become part of a salad with roasted delica pumpkin (my all-time favourite pumpkin) and radicchio.
Plus there are some Jerusalem artichokes doing their thing in a turmeric-laced brine. These slices will become a tiny, golden dice bringing a little pop of colour and hit of acid to the artichoke snack. Fried shells of the tubers filled with a purée of their flesh mixed with goats curd and topped with pear, parsley and the little pickles.
I stole the idea of the artichoke shells filled with goats curd from Ashley Finch, a chef I worked with years ago at the Goods Office. He’d developed a lovely menu full of interesting small plates but it was a bit at odds with what the Stroud Green crowd wanted from an all-day cafe/bar (avocado toast and beer snacks mainly) and he moved on to somewhere fancier.
But the artichoke thing was delicious and I think of it often. When I was casting around for inspiration of how to make it my own I looked up Jerusalem artichokes in Niki Segnit’s second Flavour Thesaurus book. There I discovered that the Japanese name for the vegetable translates as “chrysanthemum potato” and in France they are sometimes called poires de terre - “pears of the earth” - a play on pommes de terre or “apples of the earth” the French for potato. Chrysanthemums gave me the idea for the bright orange-yellow pickle and I thought some actual poires would go nicely too, matching the natural sweetness of the artichoke. Segnit also flags up parsley as a good companion and I thought a little green freshness would finish things off nicely.
I’m really excited about the combination.
The full menu for the 27th is as follows:
Snacks
Kimchi devilled eggs
Jerusalem artichoke and goats curd
Pickle plate
Focaccia
Fresh Pasta
Dauphinoise ravioli
Pappardelle with beef cheek ragu/four mushroom ragu
Seasonal Salads
Roast pumpkin with radicchio and ruby kraut
Charred greens with four thieves vinaigrette
Dessert
Preserved lemon parfait baked Alaska
The Lacy Nook is a lovely, cosy, fairy-list space, perfect for an autumnal night. It’s going to be great fun and I hope to see you there.
There are also still a couple of places if you’d like to join me for next Friday’s field-to-ferment workshop in Oxfordshire.
Tickets are £150 but In Good Taste subscribers get a discount. Use the code IGT20 for 20% off.
An introduction to vinegar
So. Let’s talk about vinegar. The word comes from vin aigre, the French for “sour wine” (I had no idea this issue was going to contain so much French revision) but it can actually be made from any alcohol. You’ll obviously have seen cider vinegars in the supermarket alongside the wine vinegars. And the classic fish’n’chip accompaniment malt vinegar is traditionally made from ale, although you may have noticed industrially-produced acetic acid making an appearance at the chippy too which is legally obliged to identify itself as “non brewed condiment” ie Not A Real Vinegar since it’s not fermented from alcohol.
The alcohol you start with doesn’t have to have been made for drinking. For example chinkiang aka Chinese black vinegar for example is made from an alcoholic mash fermented from glutinous rice. You can start a vinegar with fruit scraps that you ferment into a home-brewed hooch.
Acetobacter - acetic acid bacteria - then turn that alcohol into acetic acid.
You can make vinegar from any booze too, even stronger stuff. As more supper club prep I’ve got fennel pickling in some “ginegar” fermented from a quince gin liqueur I made last Christmas. Anything strong just needs diluting to about 7% alcohol as higher than that the bacteria don’t survive.
Anyone who’s every left a bottle of wine out after a party knows that acetobacter will show up of their own accord but you can help things along by using a starter - some “live” vinegar full of bacteria.
I’ve been making vinegar for a couple of years, basically chucking any leftover booze into a jar, adding some shop-bought apple cider vinegar (anything sold “with the mother” will work) and waiting for a few weeks. I’ve had mixed results. Some delicious things have emerged: that “ginegar”, something made with Brewdog’s Hazy Jane Guava IPA, a fig vinegar from the last fruit from the tree in the garden, various iterations of soured wine, an accidental elderflower vinegar when acetic acid bacteria managed to invade one batch of my elderflower champagne. But some not so nice ones too. A Guinness experiment fell flat. Other wine vinegars just grew yeast.
Basically I have no finesse in my technique. Which is why I wanted to tell you about Caroline Gilmartin. A fellow member of the Fermenters Guild Caroline has a PhD in microbial genetics, is a font of fermentation knowledge and runs Every Good Thing in Bristol (also an excellent online source for kefir grains, kombucha SCOBYs and so on).

Her first book Fermented Foods: A Practical Guide is a good all-round introduction to the subject, a nice balance of well-explained science and easy-to-follow recipes. This year she published a follow-up Vinegar: The Complete Guide To Making Your Own which I have been reading and loving lately.
It covers the history and science of vinegar and many different ways of making it. From my favoured chuck-it-in-a-jar method to more complicated processes such as the Boerhaave setup - daily pouring your proto-vinegar between jars filled with twigs to aerate it and hasten the fermentation.
She advises on how to choose an alcohol base (plus provides extremely useful tables on how much to dilute them by) or how to make your own, what equipment you’ll need and plenty of trouble shooting. There are also loads of delicious-sounding recipes for vinegars and pickles to make with them.
I wanted to bring you a conversation I had recently with Caroline in the hope it will be inspire you to make your own sour stuff.
A conversation with Dr Caroline Gilmartin
Clare: What’s your vinegar origin story? How did you get into it?
Caroline: Nearly 20 years ago someone showed me how to make scrap apple vinegar and I was very put off because there was a load of mould floating on the top and it didn’t taste very nice. I was not impressed at all.
Then about 10 years ago, after I had started making kombucha, I worked out that if you left your kombucha too long it turned into vinegar. And that's when I started to look into it seriously with a bit more microbiological know-how.
Then my publishers asked me to write a book about it.
Making vinegar is very simple and very complicated. There are many different routes you can take. You can measure everything. You can measure nothing. You won't necessarily end up in the same place, but you'll still end up with something that tastes like vinegar.
So I thought it would be good to be able to explain the background of what's happening and also give people the idea that you can actually start at any point along the vinegar journey.
You can start with apples. You can start with apple juice. You can start with cider.
You can let nature do its own thing or add a starter of ready-made raw cider vinegar where the microbes have already been found for you.
Clare: My introduction to the subject was the vinegar chapter in James’ book and I thought: “Oh, that sounds all right. I can do that.” So I gave it a go and had some successes and some horrible failures.
And then I read your book and got a bigger understanding of why things might or might not work. I was a bit scared at first because you talk about titration [to assess acetic acid concentration] and I haven't I haven't titrated anything! But I also liked that you made it clear you didn’t have to engage in the technical stuff to make nice vinegar.
Caroline: Oh, no, you don't have to titrate anything if you don’t want to. But it’s so fun!
Clare: If you don't have a titration set up, can you just taste to get a ball-park idea of acid levels?
Caroline: What I would recommend you do is get some shop-bought vinegar - which is five percent acetic acid - and just taste it and compare with what you’ve made. If you can dip your finger in your vinegar and suck it and not wince, it's probably not five percent!
Clare: So what sets a great vinegar apart from a perfectly nice vinegar?
Caroline: This is a very interesting question. It will be a combination of whatever you've used to get it started and the microbes that are involved in that process. I still go on about a quince vinegar I made three years ago. It was rose-coloured and floral and fruity, better than any other vinegar I've ever made and I've never managed to recreate quite that.
It depends what effect you want. If you are fermenting, for example, apples or quinces from scratch, making a cider first and then turning that into vinegar, then it will be cloudy. It won't have been filtered. It will be full of all of that goodness and complexity that the microbes can then attack and make more end products from so it will be complex and interesting.
If you use say, some crappy Meriweather cider from Sainsbury's, it's really highly filtered - it's had quite a lot of the good stuff stripped out of it. So you'll end up with something that maybe tastes much cleaner, but it won't be as complex.
Generally if you start with delicious, sweet, aromatic apples, you will make a delicious, sweet, aromatic vinegar. If you start with interesting complex wine you will make interesting complex vinegar. If you start with something flavourless, you'll end up with something that's a bit flat. It will have the acidity that you require, but nothing else and you might just want to use it to clean your windows!
Clare: And when you're adding your vinegar starter, generally speaking, you're adding raw apple cider vinegar? Is that just because it’s the easiest thing to get hold of that's got live bacteria?
Caroline: Yes. It does seem to be the most readily available live vinegar. You can wait for the microbes in the air to come and make vinegar for you. You can just leave some cider out and eventually something will come and colonise it and turn it into vinegar. But you don't know what microbes you're going to get. If you go to Aspalls, for example, they've already selected some microbes that they know make really good vinegar. So you're just taking a bit of a shortcut there.
Clare: So do you have a favourite method?
Caroline: I've got a vinaigriere [a vinegar-making vessel, usually stoneware with a tap at the bottom] that I keep on the go all the time because if there's ever any booze left over from a party you just pour them in and then they can become vinegar.
But generally it depends on how quickly I need it. If I was in a hurry I would probably want to do the Boerhaave method, which is when you tip it between two flasks each day and that aeration really speeds up the process. But most of the time I just leave it: surface method, six weeks.
Clare: Just a jar with some gauze on the top?
Caroline: Yes, because I don't need any more vinegar that I've already got! I gave away most of the ones I made for the book but I’ve still got at least 20. So there's no rush…
Clare: And once you've made it, I was interested in all your tips for keeping it at its best. Decanting into smaller bottles as you use it so it’s exposed to less oxygen.
Caroline: If you've got lots of active microbes in there and they’ve used up all the alcohol, they will start to eat their own acetic acid. So the vinegar will be destroyed, losing its acidity and flavour and turn into water.
Or you could pasteurise it as well. The jury’s is still out as to whether microbes like acetic acid bacteria have any probiotic qualities. There were some studies done in rats that suggested that they could help with sequestering glucose in the gut. But that was in rats and it's just one study. So there might not be too much harm in pasteurising it if you're going to be keeping your vinegar for a long time.
Clare: So we should beware of exposing our vinegar to too much oxygen once it’s ready. What are some other common problems?
Caroline: Yeast is a big one. Kahm yeast on the surface. It’s not harmful but can affect the flavour. Scraping it off usually does the trick.
Nothing happening is the other big one. That can be because your level of alcohol is too high and it inhibits the microbes. The acetic acid bacteria can't make acetic acid if they're inhibited by too high alcohol. Or it can be because the level of sulphites [added to wine to prevent oxidation] is too high.
Interestingly, when I wrote the book, my publishers didn’t want a troubleshooting section. But if you're trying to make vinegar, it's all about the troubleshooting! I'm always happy to answer any vinegar queries that anybody might have.
Clare: That’s a dangerous thing to promise… So finally, what is one thing that you wish people knew or one barrier that they should get past in making their own vinegar?
Caroline: It’s funny how little people know about vinegar. I asked my Instagram followers and only something like 12 percent knew where vinegar came from or how it was made. What I’d love for people to understand is that it's the microbes that make the vinegar for you. If microbes aren't involved, it's not vinegar, just acetic acid.
Thanks so much to Caroline for making the time to talk to me. Her Substack Every Good Thing is worth a subscribe.
Come back next week for a vinegar recipe!
Cultural Fun
Whilst we were in Yorkshire over half term, James’ parents took us to visit Haworth and the Parsonage Museum, home of the Brontës. I’m ashamed to say that the only Brontë work I’ve ever read is Jane Eyre. No Wuthering Heights. No Tenant of Wildfell Hall. Something I must remedy.
I liked the museum which gave a good sense of Charlotte, Emily, Anne and poor old Branwell, ever in the shadow of his sisters. Their lives were isolated and filled with tragedy and they seemed to live - slightly spookily - in their imaginations, playing elaborate games with toy soldiers and inventing whole countries and histories for them.
Sometimes they were less otherwordly though. This picture, drawn by Charlotte of her hero Arthur Adrian Augustus Wellesley, seems (very relatably) the product of a pre-teen crush.
The village of Haworth is very pretty but very touristy with every tea shop, art gallery and local gin distiller claiming some sort of Brontë connection.
They’re not all completely fabricated either. I was very ready to mock this stationery shop, joking: “Oh this must where Anne bought her writing paper.” But then it turned out it actually was.
I also had a weekend in the Peak District, a trip organised by me and my brother as an 80th birthday present for our father. We had a lovely time on the Ecclesbourne Valley Railway then enjoyed a poke around Wirksworth, a pretty town with an interesting little museum about its lead mining history.
It’s also got the StarDisc, a kind of 21th century stone circle which is nice but perhaps not worth making your 80-year-old father walk up a steep hill for…
We visited Chatsworth on Sunday morning which is always spectacular. They were gearing up for Christmas (Chatsworth gives good Christmas) so even more opulent than usual - just absurd levels of decoration and luxury. I loved it but also felt relief at finally getting out of the house and into the gardens. My head was spinning from all that brocade and gilt and carved wood. It felt like eating a very rich meal.
Then last weekend my oldest friends, Emily and Harriet, came to stay. We walked and talked a lot and it was great. We also visited the Dennis Severs House.
It’s a strange place. A five story house in Spitalfields, bought by American artist Severs in the 1970s and restored from dereliction into a museum that tells the story of a family of fictional Hugenot weavers living there over several generations.Undeniably beautiful with period furniture, fabrics and knick-knacks all adding to the atmosphere. You never meet the “residents” but are supposed to sense them, as if they have just left the room. Their belonging are strewn about and meals lie half eaten on tables. Sounds and scents are piped in, real candles and fires flicker.
It’s a “immersive art installation” conceived before before the phrase ever existed. I’d definitely recommend it, yet… I was slightly irked too. Severs (dead since 1999) chides you via signs in each room for looking at his art wrongly. “Don’t you get it?” he says. It was my second visit and I didn’t say this to Em and Harry but they both spontaneously brought it up afterwards - this feeling of being told off for not enjoying the art in quite the right way.
Perhaps Severs is right that I do lack imagination since I also would have liked a next-door museum giving more context to the social history of the Hugenots and more information about Severs himself and the project which is one of London’s truly unique museums/attractions.
Bye! See you next week!
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Fascinating vinegar chat, thank you. And I'm going to try fermenting our homegrown Jerusalem artichokes. In Bulgaria they're known as zemni yabulki, earth apples, and sometimes get fermented in with the big vats of fermented cabbage that families make every autumn.