Nukazuke: Japanese Rice Bran Pickles
Having corralled some of San Francisco’s wild yeast and soured my own crock of sauerkraut, it was time to move on to my next live food project: nukazuke. I was still a new convert to the Church of Fermentation, but a recent trip to Japantown helped immerse me completely.
I was pushing my cart around the back corner of Nijiya Market and came across bags of flaky rice bran, or nuka, the brown coating removed from rice grains during the milling process. Hmmmmm….now what could I do with those? Fortunately, not knowing how to use an ingredient has never stopped me from tossing it into my shopping cart. Browsing my Japanese cookbooks later, I found references to rice bran pickles. My go-to expert on Japanese pickles, Ikuko Hisamatsu, provided a basic recipe for traditional nukazuke in her book Quick & Easy Tsukemono.
As it turns out, “quick” and “easy” are relative terms. Homemade nukazuke are most definitely not for anyone who thinks food should be fast or convenient. But if you make your own vinegar, tend a few chickens in your backyard or brew beer, then these pickles will not phase you at all. If you’re dedicated to eating well and to providing your gut with a healthful balance of good bacteria, these pickles will be worth your time, I promise. And if you obsess about the proper method of boiling soba noodles or have perfected both chawanmushi and tamagoyaki, then consider nukazuke as serious leveling up.
For those wanting to take a half step, look for instant nukazuke kits in Japanese grocery stores: small plastic containers with the rice bran bed mixed and inoculated already for you.
Hard-core picklers, though, keep reading.
Nukazuke are one of the most rewarding foods I’ve ever made. I love their complex yet subtle sour-saltiness and their extra crunchiness. My husband and I enjoy small bites of them at simple, homey meals. A Japanese meal might end with a single bowl of steamed rice accompanied by a beautiful dish of nukazuke. A handful of radishes plucked from the rice bran make a much healthier snack than potato chips, and they’re much more delicious, I think. It’s the perfect project for spring and early summer, as vegetables return to market in all their freshness and abundance.
Nukazuke pickles — slices of cucumber, eggplant and baby daikon — add zip to a summer lunch of Korean-style salad nicoise (with bulgolgi-flavored tuna carried back from LA), pan-seared shishito chiles and miso soup with baby bok choy.
Dependable, Hard-Working, Likes Regular Attention
Like some of the better things in life, these pickles are a long-term commitment. After inoculating the bed of rice bran, known as nuka-doko, with the proper microbes, you’ll need to wait another three or four weeks before the best flavor develops. And from the first day you mix the pickling bed, you’ll need to aerate the rice bran every day by hand.
Yes, every day. By hand.
The good microbes happen to live on your hands, and they thrive with a good supply of air. The undesirable bacteria are anaerobic, so daily stirring keeps them in check. (There’s a way to leave the rice bran in deep hibernation for a period of time, used back when the winter season cut off supplies of fresh produce, but it’s not a fix to be applied too often.)
The daily stirring takes about 30 seconds, so no big deal if you’re in the kitchen anyway. In return for helping them breathe, the lactobacilli that have colonized your rice bran bed will happily transform fresh vegetables into crisp, flavorful, healthful pickles. The most delicate require only two hours, while large and dense vegetables may need to be buried for a few days. Some daikon roots are aged in the rice bran for up to a year to develop intensely deep flavors.
Last summer, John “Taikoman” Ko had connected me with Hideaki and Hitomi, two dedicated and talented cooks in Sebastapol. From Hitomi I received a few tips on starting my nuka-doko. She gave me an inspiring pep talk about how good the pickles are, how much her son loves them and how many years she’s successfully tended her rice bran bed. She even travels with her nuka-doko to make sure it receives the attention it requires — on hot days, she stirs it twice — and then makes pickles for her hosts.
Apple peels drying in the sun. They’ll lend sweetness to the rice bran bed.
To make my own nuka-doko, I adapted Hisamatsu’s formula in her book (15% salt, by weight of the rice bran) and incorporated some of Hitomi’s suggestions. The rice bran, salt and water are the two essential ingredients. In my own rice bran bed, bread speeds up the inoculation process, seaweed adds umami, apple peel lends a hint of sweetness, chiles keep away bugs and worms, eggshells clarify while contributing calcium and ginger adds its own bright flavor to the pickles.
Preparing the Rice Bran Bed
The nuka-doko serves as a medium for the microbes, a carrier for the flavorings and a gentle cushion in which the vegetables rest. Buried for two hours or two days, they emerge from their sleep brighter in color and flavor. Like vinegar and sourdough, receiving a small amount of active starter bacteria from a friend’s established colony will give you a jump start, but inoculating your own nuka bed is still pretty straightforward.
Toast the rice bran in a wide, heavy pan until it has deepened a couple of shades in color. Frequent stirring, especially as the bran browns, prevents scorching.
I use a plastic bag and a rolling pin to crush the eggshells.
Moistened bread helps attract and feed the desirable, healthful microbes to the rice bran. Ginger is one of my favorite flavors, so I add a few pieces to the bread before pureeing it with water.
While the aromatics are optional, konbu seaweed gives nukazuke that undefinable depth of flavor that makes Japanese cuisine both subtle and satisfying.
The carbo-rich bread slushee and additional cold water are stirred into the rice bran with clean hands to ensure inoculation with good germs.
A deep Cambro container becomes my pickling crock. (The lovely, traditional wooden buckets in Japantown, priced at nearly $300, will have to wait.) A few wedges of cabbage serve as my starter vegetables.
After two days in the nuka-doko, the cabbage has wilted and become salty. The wedges aren’t properly fermented, this being only the first week of the rice bran bed, but there’s a wonderful crunch to the leaves and just a hint of the nukazuke’s distinctive woodsy flavors. I could throw them out…
…or I could coat them with a heady mix of chile oil, minced garlic, grated ginger, sugar and rice vinegar to balance the salt. These end up as a host gift to Joshua and Jineui on the occasion of Olivia’s welcoming party.
My current favorite nukazuke are radishes. Above are some little cuties right after I pulled them from the fully fermented rice bran bed, about five weeks after I first mixed it all together.
And here are the radishes, rinsed and ready for munching. I eat them out of hand, stubby stem and pointy roots and all. Nukazuke are instantly recognizable by their heightened colors, with jewel-tone brightness, an elegant shimmer on the outside and a delicate translucence inside.
For extra crunch, I dried daikon for a few days at our hottest window before burying the whole root in the rice bran. (The cubes on the right were treated to a classic Vietnamese pickling brine made of fish sauce, caramelized sugar and lots of garlic.)
This is the first nukazuke I made away from home. The rice bran bed traveled with me to Los Angeles for a weeklong stay at Juli’s place in West Hollywood. These Brussels sprouts went straight from the Santa Monica farmers’ market to the rice bran bed, then emerged three days later as very yummy pickles. Remember to cut little cross-hatches into the stems to encourage even distribution of the rice bran’s fermenting friends.
Once my rice bran bed became home to a well-established, bustling colony of lactobacilli, the sprouts take only one night to pickle. They’re put to bed just before I go to sleep myself; they’re ready in the morning. If I wanted to pickle them in a few hours, I just cut each sprout in half.
Other vegetables you can bury in your nuka-doko: baby eggplants, carrot sticks, bell pepper wedges, broccoli, cauliflower, cubes of pumpkin and other winter squash, young ginger and small, tender turnips. Some recommend rubbing the vegetables with salt before placing them in the rice bran, but I now skip this step and haven’t noticed any differences in flavor or texture.
Taking Care of Your Nuka-Doko
Wash your hands and dry them well before stirring the rice bran, removing pickles and burying new vegetables. Some people like to wear gloves, but the bacteria level will remain most friendly and flavorful if there’s repeated contact with your hands.
Occasionally, you’ll need to stir in additional rice bran and small amounts of salt, as you’re removing a bit of the bed every time you take out pickles. Add aromatic ingredients according to your own taste preferences. Try mustard powder or whole garlic cloves (which can be sliced and eaten as a pickle later).
Don’t leave your vegetables in the rice bran bed too long, as they’ll turn it sour. The moisture level will vary week to week, depending on the type of vegetables you’re pickling. If you notice too much moisture, pooling at the surface or at the bottom of the container, then soak up the excess water with wadded paper towels.
If you miss stirring the rice bran for a few days, you might see a white mold growing on the surface. Simply skim it off, transfer the rice bran to a clean container and add salt. With regular aeration, the good microbes will regain their hold in a few days.
For deep storage, remove all vegetables from the rice bran. Cover its surface completely with a 1/2-inch layer of mustard powder, then a 1/4-inch layer of salt. The top should be completely white. Drape the container with several layers of thick towels, to allow a small but steady amount of air flow, and then store the container in a cool, dark place. When you remove it a few months later, scrape off the mustard and salt layers. Restart the rice bran bed with test vegetables just as you did when you first inoculated it.
NUKA-DOKO RECIPE
To hold the nukazuke for a few days, remove them when they’re ready and store them in a covered container in the refrigerator. I like to leave a thin layer of the rice bran on the vegetables to keep them flavorful and “fresh” (i.e. alive), rinsing them just before serving. Once rinsed, they’re best eaten within an hour or two.
5 ounces (270 g) sea salt
32 ounces (1800 g) organic rice bran
5 x 5-inch square of dried konbu, soaked in cold water overnight and torn into thin strips
Peel from 2 apples, removed in wide strips and dried
Shell from 3 eggs, crushed into small pieces
1/4 cup sliced dried Korean chiles, or dried chile flakes
2 inches ginger, minced
2 slices bread, pureed with 2 cups cold water
Assorted starter vegetables such as radishes, carrots, cabbage wedges or small cucumbers, rinsed and dried
1. Combine the salt with 4 cups water in a small pan and stir over medium heat until completely dissolved. Set aside to cool.
2. Toast the rice bran over medium low heat until lightly toasted and fragrant. Let cool until you can touch the bran comfortably.
3. Stir in the konbu, apple peel, chiles, ginger, bread puree and cooled salt water, using your hands and squeezing with your fingers to distribute all the ingredients evenly. The consistency should resemble wet sand. Drizzle in more cold water, if needed.
4. Transfer the mixture to a deep ceramic, glass or plastic container. Leave empty space in your container to allow room for stirring the rice bran. Bury your starter vegetables completely in the rice bran bed, and press down all over the surface to compact the rice bran well. Place a wooden drop lid or a saucer right on the surface, then drape the mouth of the container with a clean cloth.
5. The next day, stir the rice bran bed, scooping and turning it with your hands to aerate it well. The starter vegetables can be left for two to three days before being replaced with new ones. They will be overly salty and not yet properly pickled. Continue using starter vegetables for about two weeks, until the bran bed has absorbed extra moisture and developed an earthy, woodsy smell. Regularly taste the starter batches to learn how your nuka bed changes as it ferments.
6. After two weeks, taste vegetables after pickling one night. Eventually, once your nuka bed is mature, you’ll be able to pickle small or cut vegetables in 2 to 4 hours, larger vegetables in 6 hours or overnight.
7. Give your nuka-doko regular attention and enjoy the products of its quiet work.
April 24th, 2009 2:36 pm
Thy… this is fantastic! I tried to get into nukazuke a few months ago, and I searched far and wide for step-by-step instructions. I couldn’t find anything even close to what you’ve provided here, even on Japanese-language websites. As a result, my nuka-doko was nothing more than a stinky mud pit. I think I might have used too much salt, but not sure. I got most of my information from “Professor Genmai’s Bento Box,” a Japanese manga series about a college professor who is always trying to turn his skeptical students on to the joys of nukazuke (and other types of fermentation).
April 24th, 2009 5:55 pm
Andy, glad you enjoyed the post. I love that you followed instructions from a manga, especially one on fermentation. I’ll have to look for an English translation of that. As for your nuka-doko, let me know if you start another one. And feel free to check in with questions. I don’t think too much salt will make it stinky, just the opposite in fact, but the extra salt might have drawn out more liquid from the vegetables. Just blot with paper towels to absorb the excess water. You want wet sand, not stinky mud. Also, if the weather was unusually hot, you might need to stir more often. The rice bran will have a rich, earthy smell, but it definitely shouldn’t smell bad!
April 27th, 2009 4:51 pm
My mother always had a crock of nuka-doko going when I was young. I loved the smell of the fermenting vegetables but my brothers hated it. My favorite pickle was the Japanese eggplant (o-nasu). The inside turns from a pale yellow to a pastel purple. I would even eat the tough sepals of the eggplant.
My mother no longer bothers to keep a nuka-doko batch going. At the age of 79 she just makes the overnight salted pickles. I have tried to do nuka-doko but kept forgetting to stir it. (I’ve killed a few sourdough starters this way too.) However, since my mouth was watering while reading your blog, I think I will have a another go at this. Thanks.
May 13th, 2009 1:53 am
I have been doing research and would like to start my own bed. Thank you for your in-depth preparation instructions, I have been looking for something like that. I am a visual person and really like the many pictures you had. In reference to temperature and the frequency of stirring. When you say on “hot days she stirs it twice”. Can you tell me what kind of temperatures are you referring to. I live in Hawaii our temperatures range from the upper 50s F the upper 80s F. I just wanted to get an idea if I would have to stir it twice a day. I know a lot of factors are involved but the more I learn the more I may be able to make better decisions. Thank you
May 13th, 2009 11:24 am
Sharon, Thank you for sharing those memories — wonderful images. I’m definitely looking forward to making nukazuke with this summer’s eggplants. Those overnight pickles are awfully good, and I make them often myself. Be sure to come back and me know how your next nuka-doko fares.
Milton, Hot here refers to Sebastopol, where it can linger for days in the mid-to high 90s F. Here in mild San Francisco, where it also stays in the 50-80s F range, my rice bran bed has been happy with stirring just once a day. Best of luck with starting your own bed!
May 25th, 2009 6:32 pm
My nuka-doko is 3 weeks old today. I added more salt about a week ago because the starter cabbage leaves didn’t seem salty at all. Now even the overnight leaves are way too salty. (sigh) I’ve added more bran today and will hope for the best. I’ll think of it at an evolving process.
May 25th, 2009 8:10 pm
That’s great Sharon! I just stirred more bran into my bed yesterday, too. It’d been shrinking with all that asparagus I’ve been pickling.
Yes, it’s an adjustment process. And it’s ongoing. Once balanced to your tastes, its flavor may still shift slightly from week to week, month to month. Part of the uniqueness and fun…and challenge…
Good luck!
July 18th, 2009 2:24 am
How often do you remove and replace the seaweed, garlic, apple peel, and chili flakes? Have you heard of anyone having bugs actually go into the bed of rice bran? That happened to me after not checking it for a couple of days. I want to start another batch, but am hesitant.
July 18th, 2009 7:19 pm
young,
I’m glad to hear that you’ve been trying to start a rice bran bed!
Actually, I don’t remove all those flavoring, aromatic ingredients. They just slowly break down in the rice bed. Maybe every other month, depending on how many pickles I’ve been burying, I do stir in additional rice bran (toasted gently) and additional salt, as small amounts of both are removed when you dig out the finished pickles. I drape a linen napkin over my pickle crock, to let in air but keep out bugs.
I should note that San Francisco does not have as many bugs in homes — flying or crawling — as other cities I’ve lived in. I would definitely recommend a napkin or several layers of cheesecloth over your pickle bed. You might even want to secure it with a large rubber band.
Once in a while, I’ve gotten a tiny amount of white fuzz on the surface — harmless mold that I simply scrape up with a spoon before stirring the rice bran. For a one-week vacation when I wasn’t able to bring the pickle crock with me, I sprinkled the surface evenly with sea salt to cover thinly but evenly and completely, and then followed with a thin layer of ground yellow mustard. It kept the bed perfectly fine while I was away. When I came back, I scraped off most of the salt and mustard, and then stirred in the rest right into the rice bran.
Do try again, and feel free to send me any more questions you may have. Best of luck with the next one.
September 26th, 2009 2:51 pm
Thy, this is the most comprehensive explanation I’ve found, thanks much for it.
I’m trying to make pickled daikon (takuan) for my zen group. The very sketchy information I’ve been able to glean indicates that the daikon are pickled whole in large pots over long periods, maybe even several years. I don’t think they are stirred every day. Now several years is probably out of my reach, I’m aiming for several months or a year, perhaps with stirring every month or so. Do you have any ideas on how to keep the nuka healthy over longer periods without daily stirring?
October 10th, 2009 9:08 pm
The book Tsukemono by Kay Shimizu doesn’t mention any stirring of the mixture for takuan. The process includes drying the daikon first (until it can be bent into a U), placing it into the nuka-brownsugar-konbu-fruit peels and dried chili pepper mixture under weights for 2-3 weeks, letting it alone for a month to mature after that – and then you can start to eat it.
October 19th, 2009 3:11 am
Ms. Tran,
I want to first of thank you for your wonderful blog about pickling and secondly for your exquisite pictures and in depth step-by-step to nukazuke success. I have, in the past week, pulled out the first few batches of pickles from my nukadoko and, as you said, was very satisfied with the product.
During the first few weeks of caring for my nukadoko I was a bit apprehensive and second-guessing whether or not I had missed a step or spoiled the medium, but with a little patience and a lot of excitement I barreled on through to week one of delicious pickle bliss.
I had one question: I already changed my garlic cloves once, and when doing i thought, ‘Should I be changing my konbu or chili peppers anytime soon as well?’ Do the chili peppers and konbu need to changed periodically as well?
Thanks again for your insight, pictures and pickle guidance.
Asher
Akune city, Kagoshima, Japan
October 19th, 2009 4:30 am
t degroot and sharon,
You’re both right that takuan-zuke is not stirred. It’s a different type of pickle that starts with thoroughly dried daikon tightly packed between layers of rice bran. The pickling the mixture can include many of the same aromatics but typically contains less salt (5-7% by weight) and no bread, so the fermentation is completely different. A thick layer of dried greens is often used to cover the surface, and then a drop lid and heavy weights keep out air. There’s an essential layer of brine that will rise. You’ll need to leave the radish for at least a couple of months; for the famously well-aged flavors, keep it in a cool place for up to a year or more. I make a cheat version with my nuka-doko by using a smaller daikon and then just leaving it in when I stir and remove other vegetables; it’s packed in beneath the day-to-day vegetables. Two months later, the daikon was very very rich in flavor. Some don’t like it — too “funky” for them — but I love it.
Asher,
I’m delighted that you have been enjoying pickles from your very own nuka-doko! Your pickle bed is a living thing, so it will change flavor day to day, week to week, year to year. You’ll notice, with time, that the konbu, chiles and other aromatics will begin breaking down and, more importantly, that your pickles will become less flavorful. Depending on the size of your container, how often you add vegetables and what type you use, your bed will need new infusions of ingredients. Try reflecting the seasons. Recently, I have been growing out of a spicy mustard phase and easing back into the sweetness of persimmon peels. Have fun with tending your nuka-doko and enjoying your pickles! BTW, I love your posts about Akune–thank you so much for sharing your experiences.
Thy
October 21st, 2009 2:23 am
Ms. Tran,
I was just thinking about putting some persimmon (kaki) peels in my nukadoko as well, thanks for the suggestions. I was wondering, though, do I need to dry the peels like you did with your apple peels? And do i need to be careful about leaving too much fruit on the peel? Also (and I swear this is the last question, for now), could I put in mikan peels as well?
All the best.
October 21st, 2009 7:34 am
Asher–I think citrus peels would be a lovely addition! It’s certainly the season. I’ll be traveling soon to the Ehime region to visit yuzu orchards…can’t wait! As for leaving too much fruit on the peel or burying it fresh: extra moisture and sugar will always make the microbes happy. It’s a matter of how active you want them to be. If your rice bran is still pretty dry, it shouldn’t be a problem; you just might need to adjust later by stirring in more roasted bran or pickling vegetables that don’t give off a lot of moisture. If your nuka-doko is currently pretty wet, I’d take the time to peel well and dry thoroughly. It might be interesting, actually, to try pickling slices of apple. BTW, don’t worry about asking too many questions. That’s why I became a food writer! Wishing you a joyful and delicious harvest season, Thy.
October 23rd, 2009 12:07 pm
Hi there,
I’m doing this for the first time, I have my nuka-doko in a roomy baeckeoffe tureen, with a top. I’m uncertain as to what to do about covering it. Should I, or should I not? You’ve mentioned that you drape a cloth over it, but would that not leave it to dry out over time? The top might crust over. And then there’s the wafting smell, not unpleasant, but it’s not something you want to permeate your entire kitchen all the time.
October 31st, 2009 8:28 am
Hi,
This is a wonderful blog! I have been trying to find the nuka in the Boston area, so far without success, for a few weeks and have pretty much run out of ideas. Any suggestions? I don’t know if there are “rice shops” in Boston; never heard of them. Supposedly they give away the nuka…
November 9th, 2009 5:19 pm
Actually found the nuka at Japan Village Market in Brookline over the weekend.
Guido
November 13th, 2009 7:26 am
I saw on some Japanese dramas that if one adds tea leaves to the mixture some of the funky smells that people sometimes don’t like will go down. (I saw this on two separate dramas). I’m wondering if that’s true…
February 17th, 2010 7:08 pm
Excellent article! This is what I used for reference when I got started (Thanks!) There’re a couple of things I wound up doing/using that you might be interested in. I used a ceramic crock pot insert I got from Goodwill for $3.99 for my nukadoko. The other thing is I used paper towels to soak up the extra water as you suggested but realized it was getting wasteful. I wound up using a syringe (w/o the needle) for this task. I think something like a turkey baster should work for this as well. I’d first make an indentation in the nukamiso for the water to pool in.