Mountain Feed is a super-cute garden nursery and store in Ben Lomond, California, with a blog I’ve followed for years (it teaches everything from bee-keeping to cheese-making) and which answers that age-old question, “What should I do with all this zucchini?!” in my favourite way – namely, through lacto-fermentation. Lacto-fermented courgettes are a great alternative to fermented or pickled gherkins, and perfect as a condiment alongside just about any plate of savoury food, especially when they’re spiced with lots of chilli.

Lacto-fermented courgettes

I thought about making courgette chutney or relish with my excess courgettes, but we just don’t get through sweet jams and chutneys in our house. We do get through ferments, though, especially spicy ones. Lacto-fermented courgettes are fizzy, sour and full of flavour, and they’re delicious in a burger, cheddar sandwich or, once you’ve got the taste for them, pretty much any savoury plate you can imagine.

Courgettes are particularly prone to becoming too soft, so to help prevent this, add a source of tannins: a bay, oak or blackberry leaf will work well; Mountain Feed also adds a teaspoon of green tea. Refrigerate as soon as the fermentation is fully active and bubbling away (that is, after a day; or two days in summer; three to four in winter), and consume within a couple of weeks. (If your courgettes do go soft, they can be used as a flavourful probiotic to be stirred at the table into dressings, soups or stews.) To help prevent mould forming, meanwhile, ensure the courgettes are completely covered by the brine: use a fermentation weight or a clean, heavy, non-porous, non-metallic object such as another jar to keep them submerged.

To sterilise a jar, wash it in very hot water, lay on its side in a cold oven, then turn on the oven to 150C (130C fan)/300F/gas 2. When it reaches temperature, turn off the oven and leave the jar inside until it’s time to fill it. To sterilise the lid, bring to a boil in a saucepan of water, then leave in the water until needed.

Courgettes
Sea salt

Optional extras
Sprig herbs (eg, dill, thyme, fennel tops), to taste
1 pinch whole spice (eg, coriander seed, caraway seed, fennel seed)
Chillies, to taste
1 garlic clove, peeled
1 bay leaf, or 1 oak leaf or blackberry leaf
Fermentation weight, or folded cabbage leaf

Slice the courgettes into 5-10mm-thick rounds. Put a suitably sized clean jar on a set of scales, set the weight to zero, then fill the jar with the sliced courgettes. Fill with water right to the neck, leaving a 1-2cm air gap at the top, then note the total weight of the filled jar. Divide this by 100 and multiply by two, to calculate how much sea salt you require to make it 2% of the total weight, then add the salt and any optional extras to the jar, for extra flavour, then add a tannin-rich leaf to help keep the courgettes firm (I like to use it to form a cap on top of the vegetables, which helps prevent mould forming). Press the veg under the water with a fermentation weight or folded cabbage leaf, then cover loosely with the lid and leave to ferment at room temperature, and out of direct sunlight, for two to three days, or until the mixture turns effervescent and lively. Transfer to the fridge to halt the fermentation process and to keep the courgettes firm, and consume within a couple of weeks, before they go too soft.