Explainers

How to make nukazuke (bran-fermented Japanese pickles)

Master fermenter Adam James, of Hobart’s Rough Rice, on how to make crisp and refreshing nukazuke pickles.

By Adam James
Nukazuke, bran-fermented Japanese pickles
For the past six years, I've made an annual pilgrimage to Japan and, over that time, I've developed a special love of tsukemono, or Japanese pickles.
While pickles are found in many countries, for me, no one makes them quite like they do in Japan. Tsukemono are unique in their diversity and technique, and for many, a meal isn't complete without them.
Of all the different mediums for pickle-making, nukazuke, made by fermenting vegetables in a bran bed called a nukadoko, is a clear favourite. The pickle, which is made without vinegar, is distinctively crunchy, salty and sour, with wonderful earthy, umami undertones. It's also an easy process once the bed has been established, and the resulting pickle is not only delicious, but packed with good bacteria.
The bran slurry that is critical to the nukazuke-making process. Photo: Alicia Taylor
Fermenting in a nukadoko dates back to Japan's Edo period (17th century) and was born as a way to use the by-product (bran) from the rice-polishing process when making sake. This bran is mixed with sea salt and water to form a paste like wet sand, then inoculated with lactobacillus, a bacteria that occurs naturally on the outer skins of vegetables. As these bacteria multiply, the nukadoko becomes more acidic and, in turn, pickles any vegetables in it. Flavours can also be added – think seaweed, spices, ginger and chilli.
Use clean vegetable scraps to kick-start the fermentation process. Photo: Alicia Taylor
Classic vegetables pickled in nukadoko are eggplant, turnip and cucumber, but I'm currently loving beetroot, radish and carrot. An active bed will pickle a radish or cucumber in as little as six hours, and denser vegetables, a beetroot or a turnip, say, in up to five days. The longer the vegetables are left in the nukadoko, the stronger the flavour. In Japan, the most famous nukazuke is takuan, made with air-dried daikon and aged for up to two years. Fish and meat are also fermented in a nukadoko, most notably in narezushi (the precursor to modern-day sushi) around lake Biwa.
Classic vegetables pickled in nukadoko are eggplant, turnip and cucumber, but beetroot, radish and carrot work well too. Photo: Alicia Taylor
My nukadoko is always filled with one vegetable or another and has been going for 18 months. The starter, however, came from my friend, Yoshihiro, in Kyoto. He got his from a friend, who runs an izakaya, who got it from a 400-year-old kaiseki restaurant. Yoshihiro thinks it's probably more than 200 years old. It's not necessary to have a starter, though. The process resembles that of making sourdough, and it's easy to start your own.
Another vital piece of information – as told to me by an all-female group of traditional pickle masters in Kyoto, is that "you should never let anyone else touch your nukadoko. It is your hands that make your pickle better than anyone else's".

Nukazuke (Japanese pickles) recipe

Crunchy, salty and savoury, nukazuke are perfect as part of a Kyoto-style breakfast on a bowl of rice, or as a topping for congee.
Makes as much as you like // Prep time 20 mins (plus fermenting).

Ingredients

  • 1 kg rice bran, plus extra to top up the pickling mixture
  • 150 gm salt, plus extra to top up the pickling mixture
  • Aromatics (optional) such as dried chillied, dried and ground seaweed and ginger, sake, beer, kombu tsuyu
  • 2 carrots, or clean vegetable scraps
  • Vegetables to pickle, such as radish, turnip or beetroot

Method

  • 1
    In 2 batches, dry-roast 1kg rice bran in a wok over medium heat until roasted and fragrant (3-5 minutes). Cool.
  • 2
    Bring 1 litre water to the boil in a large saucepan, then add 150gm salt. Remove from heat, and stir until salt dissolves and mixture cools to room temperature.
  • 3
    Gradually add cooled rice bran, stirring well. The mixture should have the consistency of wet sand (you may need to add more water).
  • 4
    If you want to flavour the bran bed, add aromatics: dried chillies, dried, ground seaweed and ginger, say, or sake, beer or kombu tsuyu.
  • 5
    To start fermentation, add vegetable scraps or a couple of carrots to the rice-bran mixture. Bury them well and smooth the surface. Store in a dark place with an ambient temperature between 20°C and 25°C, removing scraps and adding fresh ones daily. Any scraps will do, just be sure not to use any that are dirty or going bad.
  • 6
    Repeat the throwaway pickling process, known as sutezuke, until nukadoko develops a slightly sour, fermented odour and starts to produce lactic acid (10 days to 2 weeks in warmer weather; 3-4 weeks in winter).
  • 7
    Stir the nukadoko regularly (at least once a day), to redistribute the aerobic and anaerobic enzymes and encourage a healthy, low-pH (slightly sour) nukadoko. If it gets too wet (vegetables will release water), mix in some fresh rice bran with about 13 percent of the fresh bran weight in salt.
  • 8
    Once nukadoko is smelling and tasting good (it should smell yeasty but not offensive and taste pleasant, if a little salty – a bit like a sourdough), it's ready for its first batch of pickles. I leave a radish in overnight as a very quick test to monitor the activity of the bed. The salt draws out moisture, so it'll be slightly wrinkly, but still have integrity. It should be crunchy, sour, salty and earthy. Pickling time is down to personal preference. A radish can ferment in under 24 hours, a turnip about 2 days, a beetroot 4-5 days (beetroot leaks colour, which is fine, though after a while it may stain other pickles). Continue to add new roasted bran, salt and water while vegetables are pickling to keep the mixture a wet sand consistency. Once you're satisfied with the flavour and texture, remove pickles, rinse them and store in an airtight container in the fridge. They'll keep for months.
  • 9
    Pickles are best served sliced thinly. Try them as part of a Kyoto-style breakfast on a bowl of rice, or as a topping for congee. Otherwise, add them to stir-fries, or anything and everything else. Be warned, they're addictive.