#nukadoko

Mixing the nukadoko-

The nukadoko needs to be mixed at least daily.  Hotter and more humid climates require more mixing – sometimes twice or three times daily.  If the nukadoko is kept in a wooden tub or porcelain container (i.e. not airtight) then it will also require more mixing.

Results of not mixing the nukadoko enough-

Bugs or small flies may gather and lay eggs.

The nukadoko may turn sour.

Mold may grow.

Water may pool up.

How to Mix

Clean and dry hands thoroughly, try not to use a soap with heavy fragrance or lotions.

Mix nukadoko by hand thoroughly.  Take care to mix from the the bottom of the container.  Remember, the main point of mixing is to aerate the nukadoko.

After mixing thoroughly, pat the surface of the nukadoko to make sure it is flat.  Make sure any vegetables are completely covered, and that you do not compress the nukadoko, simply flatten it.  Compressing the nukadoko will remove the air that was just mixed in.

Wipe the walls inside of container with a clean terrycloth towel or a lint-free paper product to ensure there are no stray bits of nukadoko.

Close container and store in a cool, dark place.

Adding Vegetables

Wash vegetables is clean water.

Cut daikon and nasu in half.  Do not cut cucumbers.  Nappa cabbage can be cut into quarters.

Rub salt onto vegetables.  If the vegetables are dry, use wet hands to rub the salt on the vegetables.

Bury vegetables in the nukadoko.

Vegetables buried deeper in container will pickle faster.

Lay longer vegetables flat so that they pickle evenly.

Flatten the surface of the nukadoko, wipe walls, close and store in a dry, dark place.  Flatten the surface but do not compress it.  Increased pressure on it will increase the speed of fermenting but may very well suffocate nukadoko, causing it to stall or sour.

Removing Vegetables

Wash hands thoroughly.

Find and remove the vegetables to a plate.  Generally speaking, don’t worry about wiping the excess nukadoko from the vegetable.

After removing the vegetables, mix, flatten, wipe walls, close and store the nukadoko.

Wash vegetables in cold water.

Cut and serve, or store in Tupperware in the refrigerator.

Adding Nuka

Twice a month or so, you’ll probably have to add nuka. Nuka, salt, togarashi, and konbu should be added.  Sometimes, some people would recommend that some of the old nukadoko be discarded during this procedure to allow for more new nuka.  This depends on the total volume of the nukadoko, and the water content.  Nuka that is added can be toasted or untoasted, but must be tepid.

When the nukadoko gets wet…

Wet nukadoko can suffocate the fermentation process, and cause it to sour.  To decrease water level, design a device with some combination of sieve and paper towels to soak up extra moisture.  Alternatively, remove old nuka and add fresh, dry nuka.  I usually do this, as it is easier.

When the nukadoko sours…

Try adding some combination of eggshells, Japanese mustard, or togarashi peppers.  Depending on your climate, try leaving the lid off a little or mixing 3+ times per day.  Also, add some salt to slow down the process.

Why Nukadoko Turns Sour

Too little air (not enough mixing)

Too watery

Chemicals from soaps or lotions on hands

Bacteria from unwashed hands or vegetables.

The Container

Personally, I’m using a large plastic Tupperware-style box with an air-tight rubber seal.  I've seen people use plastic bags, Tupperware, ceramic urns, and cedar tubs.  In my opinion, wood seems to be the best because it allows some air through and adds flavor.  Used sake "taru" are supposed to be quite good.  Also, since one wants to lay the vegetables flat, remember that the container should be as wide as the largest vegetables are long.

Dealing With Your Nukadoko When You Travel

If you are leaving for a few days, give it a good mix cover the top of the nukadoko with salt.  Seal the container well and place in the back of your refrigerator.  Upon returning, throw away the top layer of nukadoko.  If your trip is longer than a few days, then you will need to leave the nukadoko with a caretaker.  It will be imperative that the nukadoko is stirred regularly by hygienic hands during this time.

Materials commonly added to Nukadoko

Nails - The iron in the nails prevents eggplant surfaces from oxidizing and turning brown. Iron paperweight sized products are available which do the same thing.

Garlic - Garlic adds flavor and aroma.

Katsuobushi - Katsuobushi is the shaved dried mackerel used to make lots of Japanese dishes. Pieces chip off of a block can be inserted into the nukadoko.  They add a nice woody flavor.

Japanese Mustard - Helps control the fermentation of nukadoko and adds flavor and aroma.

Dried Shiitake Mushrooms - Adds flavor and aroma.

Bread Crumbs - Helps fermentation and adds flavor.

Beer - Helps fermentation and adds flavor.

Chili Peppers -Helps control fermentation, adds flavor.

Dashi Konbu - Dried kelp. Adds flavor and depth to the nukadoko, as well as maintains its health.

Salt - Salt is the single most important part of the nukadoko.  Too much kills the flavor, too little lets the fermentation get out of control.  The balance of the salt on the vegetable is essential for the final saltiness of the pickle.

The Art of Tsukemono

糠漬

I dare to say that every Japanese household has its own nukadoko and I dare say every child hates that smell when okaasan or obaachan is mixing it.  I vividly remember eating tsukemono when I was little.  Nukazuke was my favorite after-school snack or side dish with dinner.  Little did I know that the nukadoko I despised so much was cultivated for over 30 years, and that was the reason for the bounty I enjoyed.  Like so many other things in life, the quality of the nukadoko and the tsukemono it produces is directly proportional to the effort and care that goes into maintaining it.

糠床 

Creation of nukadoko is, easy; its perfection however, is not.  Nukadoko must be mixed daily.  This is primarily to stop water from pooling up and to add air to the mixture.  This is vital because of the lactobacillus probiotic living and fermenting in the bed.  I’ve been making my own lately, largely because of the nostalgia associated with consuming it.

The process begins by acquiring 糠(nuka), the bran from milled rice, and toasting it.  Many people do this with a large wok or clean frying pan.  I tried this method, but I found a baking dish in the oven to be much more accurate, controllable, and convenient.  Opinions differ on exactly how much you should toast the bran, but one thing is clear, not too much.

Once it is toasted it is allowed to cool and the water is prepared.  Fresh, clean water is brought to a boil and quality sea salt is dissolved in it.  How much salt?  Opinions vary, though goodly amount, but not too much.  Obaachan says “until it looks right.”  It will also need to cool before being added.

Next comes the starter: crack open your favorite (light) beer, take a sip, and pour the rest into your container for the nukadoko.  Now you’re ready to start mixing.  Clean your hands well, and mix the beer, salt water, and nuka well.  The mixture should be very earthy, like wet sand or so, and quite tepid.  This is the base for nukadoko, but it won’t produce very good results.  From here, you’ll need to add 種, a word that means seed… or source.  The bits that you add become the source of the flavoring of your nukadoko.  Common additives include togarashi peppers, miso, konbu, katsuoboshi, garlic, ginger, mustard, and egg shells.

Feeding the Fermentation

This part is a little strange, but you’ll need more種.  You’ll need to place common seasonal vegetables into the nukadoko, and let them sit for a day.  Then remove them and discard them.  Mix the nukadoko well, and add new vegetables.  This is important for beginning the fermentation process.   I fed mine with some old carrots and cucumbers.  After about a week or so, the nukadoko will become more pungent, and it will be ready to produce tsukemono.  This step is important for maintaining nukadoko, even when you are not regularly producing tsukemono, it is important to keep “feeding” the nukadoko.