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Wulf's Kitchen: Koji-Marinated Fish

Serves: 2-3
Prep Time: 4-6 hours, or overnight
Cook Time: 8-10 min
Difficulty: Easy

Koji, on its own, is the ideal marinade. It’s salty, sweet and umami akin to parmesan and miso. A traditional food of Japan, koji is a grain, in this case rice, inoculated with a desirable mold (like cheese is) and fermented until the desired flavor profile is reached.  


As a flavor enhancer, koji lends its magic to all types of fish. Try it with any salmon you like, its cousins ChalkStream Trout and Arctic char, or white fish like cod, haddock and halibut. For these photos we used Arctic char from Iceland since the thin fillets would cook quickly.   


We love this recipe because it's simple, low-maintenance and works every time. It only involves about 5 minutes of active preparation. The rest is marinating and roasting time. When using koji, you don’t need to use additional salt when cooking your fish.  


Find Koji here.



  • 1 pound fish fillet, skin on or off
  • ¼ cup rice koji (see link above)
  • oil for cooking




Pat the fish dry with paper towels and place the fillet(s) in a container with a fitted lid (or have plastic wrap to cover).


Cover the fish with koji, using your hands, to ensure even and complete coverage on all sides. Cover and let marinate in the fridge for 4-6 hours, or overnight.


Let the fish come up to room temperature while you preheat your oven to 425 degrees Farenheight. Place parchment paper or tin foil on a baking tray and spray, or coat lightly in oil.


Brush the excess koji off the fillet before cooking or leave it on for a stronger effect.


Roast the fish for about 8-10 minutes until the fish is firm to the touch and flakes easily with a fork.


Enjoy with a salad, rice, pasta, or whatever you would like.