How to make nukazuke, or bran-fermented vegetables – recipe

“It’s kind of like a compost recipe,” said Dr Johnny Drain, a chef-scientist and fermentation expert who works at Douglas McMaster’s restaurant Silo. His role there is to transform food that would otherwise go to waste into wondrous ferments that add flavour and complexity to the menu. Drain explained how you can mix vegetable peelings, egg shells and persimmon skins, which are rich in lactic acid bacteria, into a base of rice, wheat or oat bran, or even cacao or coffee husks, to make a “nukazuke bed”, a traditional Japanese way of fermenting vegetables. Rice bran is a byproduct from processing and polishing rice, and contains many nutrients, as do wheat and oat bran, which are a great alternative for nukazuke made in Britain.

Nukazuke, or bran-fermented vegetables

Bran fermented pickles are crisp, sweet and sour, and can be flavoured with all sorts. Persimmon skins turn white vegetables a subtle yellow, egg shells help reduce sourness, and fruit and vegetable peelings impart their natural flavours, as well as adding other beneficial lactic acid bacteria. For those who like spice, throw in a few teaspoons of dried chillies or sansho pepper.

If you maintain your nukazuke bed well, it can be reused indefinitely – Dr Drain told me that in Japan, some pickle makers have nukazuke beds that are 50 or more years old. To keep your bed from going too sour or moulding, keep it in a cool, dark, dry place and stir once or twice a day. After making a batch of pickles, if the nukazuke bed becomes too wet, add more bran and salt as necessary, and aim to keep a ratio of 15% salt to 100% bran (ie, if you add 100g bran, add 15g more salt).

Makes About 500g pickles

500g oat, wheat or rice bran, roasted (do not use any oil during roasting) for 6-8 minutes at 200C (180C fan)/390F/gas 6
75g salt
200ml stale beer or water
50-100g optional extras – fruit or vegetable peelings, garlic, ginger, egg shells, persimmon skins or kelp
500g seasonal vegetables – gherkins, small finger aubergines, cabbage, daikon, turnips, radishes, fennel, etc

Use your hand to mix 500g toasted bran with 75g salt and the beer or water. Add more water as necessary, to create a mixture the consistency of wet sand, then scatter in your chosen optional extras and leave to ferment for three days, turning once a day.

Next, pour a third of the mixture into a wide, non-metallic jar or tub and press down. Place half your chosen veg on top and cover with a third more of the bran mixture. Lay in the remaining vegetables and pack with the last third of bran on top. Cover with a clean tea towel or muslin, place a heavy weight on top and store out of direct sunlight for three days. Turn the mixture once a day, packing it down and replacing the weight each time. The pickles will keep in the nukazuke bed for up to a month and, once removed from the bed, they’ll keep in the fridge for up to a week.