Over the past few years, shio koji has gone from a niche Japanese pantry staple to a buzzword in kitchens from New York to Paris. It begins as a simple mixture of koji, rice, water, and salt, but fermentation transforms it into a seasoning that amplifies the flavors of whatever it’s added to. It’s a natural source of umami that can boost everything from salad dressings to pan sauces, but where it really shines is in marinades.
What is Shio Koji
Shio koji is a liquid seasoning made by fermenting rice inoculated with koji (Aspergillus oryzae). This beneficial culture also transforms rice and soybeans into cornerstones of Japanese cuisine like miso, soy sauce, and sake. Once the rice is inoculated with koji, it’s incubated with salt and water. During fermentation, amylases convert starches to simple sugars, and proteases break proteins into peptides and amino acids. The result is a natural blend of sweetness and umami that partners with salt to create a balanced condiment for seasoning a wide range of foods.
How to Make Shio Koji Marinade
After the enzymes work their magic on the rice, liquid shio koji develops a balanced mix of salt, sweetness, and umami, so you can use it straight from the bottle as a marinade without adding anything else. Those enzymes also make shio koji an effective tenderizer, rendering everything from chicken to steak to seafood tender and juicy.
With its mild aroma and abundant flavor, shio koji also makes an excellent base for custom marinades. For fish and seafood, I like adding a little grated ginger to smooth over any fishy notes. For chicken, try herbs like rosemary, thyme, or tarragon. And for steaks and other meats, freshly cracked black pepper and spices such as cumin and coriander create a bolder, spiced profile. Think of shio koji as a balanced foundation for a marinade that you can steer in any direction with aromatics, herbs, and spices.
How Long to Marinate
Marination time with shio koji depends on the size, thickness, and type of protein. Fish and seafood can be ready to cook after as little as 1 hour, though up to 1 day of curing improves flavor and texture. For poultry, plan on a couple of hours to 1 day. Tough cuts of pork, lamb, or beef benefit from a full day. Marinating for more than a day can over-tenderize the protein, leaving it with an unnaturally soft texture.
Cooking Shio Koji Cured Fish
The natural sugars in shio koji can cause it to burn, so there are a few important points to remember.
Remove excess marinade: Once it’s done marinating, the shio koji has already seasoned and tenderized the protein. Removing any excess marinade from the surface of your meat or fish will help keep it from burning.
Use moderate heat: Cook your meat or fish over moderate heat so it doesn’t scorch before it’s cooked through. Bake in an oven preheated to 400°F (200°C), or pan-fry with a little oil in a non-stick frying pan over medium heat.
Ingredients
- 4 grams ginger (~1/2 teaspoon grated)
- 1/3 cup shio koji
- 450 grams black cod (4 fillets)
Nutrition Facts
Instructions
- Grate 4 grams ginger and mix it into 1/3 cup shio koji.
- Pat 450 grams black cod fillets dry with paper towels.
- Coat each piece of fish with an even layer of the shio koji marinade.Cover and refrigerate for at least 1 hour, preferably overnight.
- When you are ready to cook, preheat the oven to 400°F (200°C). Using yourfingers, swipe away as much excess marinade from the surface of the fish aspossible.
- Set the fillets on a parchment-lined sheet pan and bake until cookedthrough and just starting to brown around the edges, about 10 to 15 minutes.
