Fermented Turnip Sushi (かぶら寿し, Kabura-zushi)

Ingredients

Equipment Needed

• •Nonreactive glass or enamel container
• •Japanese pickle press, or a small plate with a clean jar of water as a weight
• •Sharp knife for clean turnip slits

Instructions

1. 1

   Salt the yellowtail

   Cut the buri into pieces about 5cm long and 7mm thick. Sprinkle with the 20g salt on all sides, set in a nonreactive dish, cover, and refrigerate for 24 hours. The salt firms the fish and draws out surface moisture, which gives the kōji a clean piece of fish to work on instead of a watery one.

   Use fish you would trust for raw eating after curing. If the smell is strong or the flesh looks dull, change the dish. Nothing good is hidden by fermentation.
2. 2

   Cut the turnips

   Cut the peeled kabu into rounds about 1.5cm thick. Make a deep horizontal slit in each round, stopping just before you cut through, so it opens like a little book. Salt the turnips with the 18g salt, weight lightly, and refrigerate for 24 hours. Salting makes the turnip flexible enough to hold the fish without snapping, and it seasons the vegetable all the way through.

3. 3

   Prepare the kōji

   Warm the water to just body temperature, about 35C, then mix it with the rice kōji, cooked rice, mirin, and sugar if using. Leave it covered at room temperature for 2 to 3 hours, until the grains soften and smell gently sweet. Don't make it hot. Kōji is alive enough for our purposes, and hard heat dulls the enzymes that make the sweetness.

4. 4

   Rinse and dry

   Rinse the salted buri quickly under cold water and pat it very dry. Drain the turnips and press them gently between towels. This is not washing away the work, only removing harsh surface salt. Dry surfaces let the fish, turnip, and kōji meet cleanly instead of sliding around in brine.

5. 5

   Fill the turnips

   Open each turnip slit and tuck in one piece of buri. Do not overfill. The turnip should close around the fish with a little pressure, like a quiet mouth keeping a secret. If it gapes open, the piece of fish is too thick.

6. 6

   Layer with kōji

   Spread a spoonful of kōji mixture in the bottom of a clean glass or enamel container. Lay in the stuffed turnips in a single layer, scatter over carrot, konbu, and chile if using, then cover with more kōji. Repeat until everything is packed, finishing with kōji on top. The kōji must touch the food, because that contact is where the sweetness, mild sourness, and fragrance develop.

7. 7

   Press and mature

   Cover the surface with plastic wrap or a clean piece of parchment, set a small plate on top, and weight it lightly. Refrigerate for 4 to 6 days, turning the pieces once after the second day with clean chopsticks. The light pressure keeps the fish and turnip in contact with the kōji; too much weight crushes the turnip and leaves you with a pickle that has lost its manners.

   Keep it cold, below 5C, for a home kitchen. Traditional winter rooms were cold for a reason. Warmth makes this dish reckless, not better.
8. 8

   Serve restrained

   When the turnip smells sweet, gently sour, and clean, lift out the pieces and wipe off only the excess kōji. Cut larger rounds in half if needed. Serve chilled or cool, with a thread of yuzu peel. The kōji clinging to the surface is part of the dish, so don't scrub it bare.

Chef Tips

• •Ask the fishmonger for winter buri suitable for curing and raw eating, not any yellowtail that happens to be in the case. This dish begins with the fish counter, not the knife.
• •Kabu is the turnip wanted here: tender, sweet, and fine-grained. If you use a harsh storage turnip, salt will make it edible, not graceful.
• •A Japanese pickle press is useful, but a small plate and a clean jar of water do the same work. Light, even pressure is the point.
• •The finished smell should be sweet, lactic, and faintly of the sea. If it smells rotten, alcoholic in a harsh way, or fizzy and angry, throw it out. A teacher can forgive many things, but not bravado with fish.

Advance Preparation

• •Begin 6 to 8 days before serving: one day to salt the fish and turnips, then 4 to 6 days to mature in kōji.
• •Once mature, kabura-zushi keeps refrigerated for about 5 days. Keep it covered and use clean utensils each time.
• •The kōji mixture can be started the morning you pack the turnips, but don't make it days ahead. It should be sweet and active, not tired.

Frequently Asked Questions

Nutrition Information

1 serving (about 145g)