Dearbhla Reynold's Tomato Salsa



This ferment is magical for a number of reasons.

Firstly, it doesn't involve cabbage. People tend to think that vegetable ferments must always involve cabbage. This is not true and this recipe is proof of that. I know, I know, tomatoes are fruits - but I am counting them as a vegetable here.

Secondly, it is such an adaptable ferment - we eat it on toast, we eat it with curry, we eat it as if it were a chutney with cheeses, we eat it in our guacamole, we stir it into our hummus. You get the picture.

Thirdly, due to the sugar and water content of the tomatoes, it gives up moisture very easily and it gets very active very quickly - lots of moisture and lots of bubbling carbon dioxide. It is a joy to watch it ferment away - just remember to pop your kilner onto a plate, because the combination of moisture and gas means the juices sometimes escape the kilner whilst you are not looking!


dearbhla's RECIPE


1 litre Kilner Jar, washed in hot water or that has been through the dishwasher.

An empty, clean jam jar (with a lid) the bottom of which just fits inside the mouth of the Kilner jar. All will become clear in due course.

A flat-ended rolling pin or equivalent for bashing the vegetables into the Kilner jar.

A large mixing bowl

A set of scales.



8-10 ripe tomatoes
2 red or green peppers
2 medium onion (I use red ones)
1-2 garlic cloves
Juice of 1 lime
Handful of fresh coriander
1/2 tsp of chilli flakes
1/2 tsp of cumin seeds

A pinch of smoked paprika
A turn or two of freshly ground black pepper





Roughly chop the tomatoes, peppers and red onions.

Finely chop the garlic cloves, coriander, and chilli.


Put the empty mixing bowl onto the scales, then zero the scales so that you can weigh the total weight of all the prepared vegetables.

Put all the vegetables into the bowl on the scales.

Add the spices and the lime juice.

And then make a note of the weight of the vegetables excluding the weight of the bowl.


This volume of vegetables normally weighs around 1kg. For every 1kg of vegetables, we need 20g of salt – i.e. a ratio of 2%. So, if your vegetables weigh 900g, you will need to weigh out 18g of salt. The maths is simple – divide the weight of your vegetables by 100 and multiply that by 2 to give you the weight of the salt you need. Having said that, I often do this recipe with 1.5% salt, so you can play around with the ratio a little to suit your taste.

Weigh out the correct amount of salt into a separate bowl. Too many times, I have left the bowl of vegetables on the scales and weighed out the salt straight into the bowl of vegetables. One slip of the hand and then I have too much salt in my vegetables and I have to start to try to pick some salt back out.

Once weighed, pour the salt into the bowl of vegetables, roll up your sleeves and massage the salt into all the vegetables thoroughly.

Once you have done this, leave the bowl of salted vegetables to stand for ½ an hour or an hour. This enables the salt to draw out moisture from the vegetables with zero effort from me. With tomatoes, this happens very easily. And we need this moisture, as you will see in a minute.


Once the vegetables have had their rest, you will be able to feel that they are softer and moist.

Now, they are ready to be tamped.

Take your Kilner jar and your flat ended rolling pin.

Cover the bottom of your Kilner jar with a few handfuls of vegetables and then tamp them down. This is not bashing. This is a rhythmic tamping – a gentle bashing.

Add the next few handfuls and repeat. The volume of the vegetables should reduce noticeably and, after a bit of tamping, you will see juices starting to ooze out as you press down with your tamper. This is what we need – the juices flowing. Because tomatoes are so full of moisture, they release it very quickly. And this means that you do not need to work very hard on the tamping phase (another reason why I love this recipe!).

Keep going until the jar is almost full – you need a gap at the top to act as your bacteria buffer zone.

So by now,  you should have squished all those vegetables into your 1 litre Kilner jar and when you push down on the vegetables, there should be a good amount of juices at the top of the jar.

These juices are key. Whilst fermenting, our vegetables need to be below a seal of moisture. The juices we have squeezed out of the vegetables form the “seal” at the top of the jar to keep oxygen away from our vegetables to, amongst other things, minimise mould growth.


In order to stop the vegetables floating up into our juice seal and breaching it, I fill my clean jam jar with water, put the lid on and push it down into the Kilner Jar. Its weight keeps the vegetables mostly under the juice seal.

I used to be very particular about this and got a bit perturbed if the odd bit of vegetable appeared round the side of the jam jar bottom. Now I am less concerned. So long as the majority is submerged, I am happy. If the odd bit floats up, I just shove it back under the fluid line.


Put your kilner full of salsa somewhere at room temperature. Put it on a plate or dish to catch any overflowing juices. Then sit back and let the magic happen. Fermentation.

In brief, this is what fermentation is: there is a range of bacteria all over the vegetables, even if they have been washed. The salt reduces the levels of bacteria we don’t want to encourage. The lack of oxygen does the same. The bacteria that like salt and no oxygen dominate and produce acids – acetic acid and lactic acid, mainly. This is the perfect environment to allow the naturally-occurring lactic acid-producing lactobacillus species to dominate. They digest the sugars in the vegetables, produce lactic acid, which preserves the vegetables and, at the same time, produce all sorts of beneficial by-products in so doing, including B vitamins.


In the first few days, all we need to do is keep our fermenting ferment at normal room temperature. It is also important to occasionally push down on the jam jar weight to make sure the salsa hasn’t floated up. Initially, carbon dioxide is a by-product and these bubbles of gas can make the salsa float up. The carbon dioxide production slows after 2-3 days.

Tasting and Eating

I leave my salsa at least 21 days. I taste it then – it is normally full of flavour. If it tastes good to me, I pour off the excess juices (or drink them) and then store the salsa in the fridge (slows bacterial fermentation right down) and eat for lunch or dinner or sometimes even breakfast. This salsa is delicious on toast, it is amazing with curry, with guacamole, wih hummus, with labneh. With pretty much anything really. Often though, even though it tastes delicious, I wait longer. The average time I leave mine before slowing the fermentation by refrigeration is around 4-5 weeks. The taste is different then – the vegetables softer, the flavours more complex. It is a matter of personal taste when you start to eat it.

Glitches and Hitches

Don’t worry if a bit of mould grows on the surface – it means you haven’t submerged the salsa properly. Just remove the mouldy bit, keep calm and carry on.

Don’t worry if foam collects on the surface – this is not unusual either. I scoop it off with a clean spoon and push down on the jam jar weight to force more moisture out and up.

I have never had to throw away a ferment, other than the courgette ones! Really, anything goes. And remember, it is NOT ROCKET SCIENCE, so experiment to suit your own taste buds and your own gut. It is magic.

Dearbhla tomatoes.jpg


This recipe came from Dearbhla Reynolds wonderful Book The Cultured Club. She kindly agreed to let me put it up here because, like me, she dreams of everyone getting to enjoy fermented salsa.


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