Jerusalem artichoke ferment
Jerusalem artichokes are a bit special to me. I love the plants, themselves, with their beautiful yellow flowers and tall gangly stems. And in the Autumn and through the Winter, when the above-ground parts have been trimmed back, beneath the soil nestle these nutritious vegetables, a bit like hidden treasure.
They are packed with a prebiotic fibre called inulin. Prebiotic means this fibre selectively feeds the beneficial microbes in our gut (who then go on to produce a range of metabolites that interact with the cells lining our gut, with our immune system, with our nervous system and so on). And alongside this fibre, Jerusalem artichokes also contain Folate, Vitamin C, Vitamin A and a range of minerals.
But these vegetables are much maligned for being difficult to peel and for making us fart. Their nickname in this household is “grenade” or “fartichoke” because they can cause explosions! The hot air is a byproduct of active fermentation in our large intestine. If you have gut issues like IBS or SIBO, Jerusalem artichokes can play havoc with your innards. But for most of us, a bit of excess gas is just a good sign that your beneficial microbes are feasting and fermenting that inulin.
There are two very good reasons to ferment them. Firstly, you are enabling a lot of that carbon dioxide-producing fermentation to occur in the kilner jar rather than in your gut, so eating fermented Jerusalem artichokes will result in less farting. I know this only from research on myself (but do email me with your findings!). More importantly though, (given that farting is a very normal thing to do) they taste quite incredible fermented. I never get bored of the unique flavours and textures that are created through microbial action.
This ferment is stunning. The horseradish taste comes through, but it is sweet, oh so sweet. Then comes the nutty, earthy Jerusalem artichoke and then comes the chilli kick (mine are an utterly wicked type I grew from seed).
This ferment will fit into a 1 litre kilner jar or equivalent. You won’t believe this when you see the pile of vegetables chopped up at the start, but I speak the truth.
We consume fermented vegetables with pretty much anything here, with salads, with curries, mixed into hummus. They make a great addition to most dishes. But this one, I can simply eat from the spoon (remember not to double dip the spoon though…)
Jerusalem artichoke ferment recipe
Ingredients
800g Jerusalem artichokes, washed thoroughly
200g fennel
3 red chillis (I put the seeds in too)
2tbsp grated horseradish
Salt
Equipment
1 litre Kilner jar
Washed in hot water or that has been through the dishwasherA flat-ended rolling pin or equivalent (could be your fist) for bashing the vegetables into the Kilner jar.
A large mixing bowl
A set of scales.
Method
Chopping
Thoroughly wash the Jerusalem artichokes, cutting out any wormy bits. I do not peel mine because this is very time-consuming and I know where my Jerusalem artichokes have been as I grow my own. You may want to peel yours if they are not organic/home grown, but this is not necessary if you don’t want to.
Set one whole Jerusalem artichoke aside (you will see why later).
Spiralise, grate or cut your artichokes into very small strips (see image, above).
Cut the fennel lengthways into thin slices and then widthways into manageable bite-sized pieces.
Cut the chillis into tiny pieces.
Grate the horseradish.
Weighing
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.
And then make a note of the weight of the vegetables (excluding the weight of the bowl).
Salting
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.
Weigh out the correct amount of salt into a separate bowl. 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. And we need this moisture, as you will see in a minute.
Tamping
Once the vegetables have had their rest, you will be able to feel that they are softer and moist. If you squeeze some in your fist, moisture should now drip out between your fingers. If not, give the veg another good massage. Now, they are ready to be tamped.
Take your kilner jar and your flat ended rolling pin (or your fist). Cover the bottom of your kilner jar with a few handfuls of vegetables and then tamp them down.
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. If there is a distinct lack of juices, the chances are you jumped the gun on the waiting time. And this means that you will need to work harder on the tamping phase to squeeze out the vegetable juices.
Keep going until the jar is almost full – you need a gap at the top to act as your bacteria buffer zone. 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 so as to exclude air. 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.
Weighting
Sometimes, I will use a cabbage leaf and a whole Jerusalem artichoke to stop the vegetables floating up through the juice seal and being exposed to air. To do this, you steal a cabbage leaf, fold that whole cabbage leaf and wedge it down over the chopped veg.
Push the leaf down under the fluid level.
Then, take the Jerusalem artichoke and put that on top. Close the kilner lid and, as you do so, it should press down on the Jerusalem artichoke, which will push down on the cabbage leaf and help to hold all your developing ferment beneath its own fluid.
Having said all this, I rarely bother, because generally, the lactic acid bacteria acidify the process promptly, excluding the growth of any other microbes, even if a few bits of veg float up through the fluid at the top.
Waiting
Sit back and let the magic happen. Fermentation. There are 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 bacteria 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. You will want to put your kilner jar on a saucer to catch any juices that will be forced out of the kilner during fermentation.
Burping
In the first few days, all we need to do is keep our fermenting ferment at normal room temperature. Initially, carbon dioxide is a by-product and these bubbles of gas can force fluid out of the kilner (hence putting it on a saucer to catch these juices). The carbon dioxide production slows after 2-3 days.
Tasting and eating
I normally leave my ferments at least 21 days, but this ferment tastes amazing from around 5 days and just keeps on developing as the fermentation process continues. The veg is normally very crisp and crunchy. If it tastes good to me, I move my ferment to the fridge (slows bacterial fermentation right down) and eat for lunch or dinner or sometimes even breakfast.
Glitches and hitches
If you have any questions or concerns about your ferment, consider signing up for a paid subscription to Substack, where I can answer any queries you have via the chat function..
