Lacto-Fermented Fennel

Fermented foods are very high in healthy probiotic bacteria and provide a huge range of benefits including; aiding digestion, improving overall gut health and gut flora and helping to boost immunity. Our delicious Lacto-Fermented Fennel recipe can be applied to many different types of vegetables, such as carrot, beetroot, celery, celeriac, pumpkin, or parsnip.



  • 500g fennel (approx. 2ea. medium bulbs) including stalks and fronds
  • Large pinch of whole fennel seeds
  • 100ml water kefir (optional-see notes)
  • 6 slices of lemon peel
  • 4 fresh bay leaves
  • 300ml filtered unchlorinated water
  • 30g Fine Sea salt (grind sea salt flakes in a mortar and pestle or spice grinder)



  1. To begin, weigh the 1-litre jar and note down the weight. Sterilize the jar – a dishwashing machine can do this. Alternatively wash the jar with hot soapy water, rinse with fresh water and place in a 100c oven for 10 minutes. Air dry and cool jar.
  2. Trim the tops, stalk and outer layer off the fennel and wash all well. Reserve one piece of the outer layer of the fennel bulb. Put the bulbs aside and pass the trimmings through a juicer – you should get approx. 150ml liquid. If the fennel you have doesn’t have the stalks or fonds attached to juice omit this step and just use filtered water in the next step.
  3. Add the fennel juice to the jar, along with the fennel seeds, lemon zest and bay leaves. Any other aromatics you fancy, can be added, such as whole coriander and carraway seeds, juniper berries, garlic, and chilli flakes.                                        
  4. Cut each fennel bulb into 6 or 8 wedges, depending on size and place in the jar. Try to get as much fennel in as possible and fill the jar as much as possible. Top up with the water kefir and filtered water until fennel is completely submerged. And water to around 5mm under the rim of the jar. This helps cut off any oxygen and potential contamination from unwanted microbes during fermentation.
  5. Weigh the jar again and subtract the original weight of the empty jar. Divide the number you get by 100 then multiply that by 3 to find out the amount of salt needed (3%). It will be very close to the 30g you started with. Add the salt, place the lid on the jar, and shake well to combine ingredients and dissolve salt. Take lid off jar. The level of liquid and fennel should be near the top of the jar. Place the reserved outer piece of the fennel bulb on top of fennel, trimming to fit if necessary. This is to weigh down, and keep fennel submerged in the liquid. Replace the cap tightly.
  6. Leave to ferment for around 3-7 days – the length of time needed will depend on the warmth and humidity of the room it is stored in and how tangy you like the flavour (generally, 5 days is sufficient.) Release the lid every day or so (called burping!) during hot temperatures, to allow trapped gas to escape.
  7. Once ferment is ready to your liking, store in the fridge.


This is a lacto style ferment. Lacto refers to lactic acid (also the sour flavour in the ferment) and the reaction between the salt and the cell walls of the vegetable, which helps keep the vegetable crunchy. The crunch is a nice feature of this style of ferment. The recipe makes a decent sized batch but will last for a long time in the fridge, so long as the fennel stays submerged in the brine. 

The kefir is optional as can be substituted with any liquid from a fermented product (such as yoghurt whey or sauerkraut liquid) This helps to kickstart fermentation but is optional since fermentation should occur naturally anyway. Uses for this product are varied… it’s delicious simply sliced as a side, or in a salad, and pairs particularly well with seafood.