Welcome to the Wonderful World of Koji

Koji is a specific mold grown on a starch medium that can make food extraordinarily tasty if you simply mix a few ingredients together and wait. Alchemy is a power or process that changes or transforms something in a mysterious or impressive way.

You may not know what koji is, but you’re intrigued by what you’ve heard it can do. Maybe you’ve been told that it smells like the most intoxicating combination of grapefruit, chestnuts, honeysuckle, and mushrooms. It may sound hard to believe, and you want to taste what’s actually possible. Well, it’s likely you already have. You probably even have a bottle of it in your pantry right now. We’re talking about soy sauce, a widely enjoyed condiment that is part of the common culinary language practically everywhere in the world, a familiar friend and a known tasty quantity that you’ve been dipping dumplings and sushi in longer than you can remember. Let’s not forget the countless splashes you’ve added to marinades as a tried-and-true accent to make whatever you grill, sauté, or roast shine. As delicious as soy sauce is, it only scratches the surface of what can be done with koji.

To help make it easier to understand in application, we like to describe koji as a seasoning. Consider salt—the most basic seasoning that makes everything taste better. We’ve all experienced food that lacks the right amount—and we also quickly understand when there’s too much. Think about a tomato at peak ripeness to be sliced and eaten. Now remember when you tasted the mind-blowing flavor of that tomato when you sprinkled a touch of salt over it; it’s possible you can’t imagine eating it any other way. The same goes for the primary driver of koji, umami (flavor body). Have you ever tried making a sauce without the bits of meat stuck to the pan after searing, aged cheese, mushrooms, tomato, seaweed, miso, or the like? The results will be missing depth of flavor, one that cannot be realized without amino acids, the fundamental components of proteins.

Photo by Peter Larson

We are wired to taste umami and feel satisfaction, because it’s an indicator of nutrition. When food lacks this savory taste, our bodies tell us it’s not fulfilling. That’s why we simmer water with bones to create a stock that ultimately makes a soup more satisfying, which doesn’t take much protein to achieve. However, the ability to coax the flavor and nutrition out of protein requires cooking skills and/or preservation methods driven by heat, microbes, and time. The magic of koji is its ability to give us delicious foods with less effort and time. In some cases it works overnight. Simply applying koji to foods ahead of cooking leverages enzymes to accelerate the flavor generation process; the food is already delicious before you start. Koji works in concert with practically any food preparation technique you know, with very little adjustment.

On the sweet side of things, we are forever chasing ultimate fruit ripeness for the sugars. Sweetness is another flavor element that is an indicator of essential nutrition, and one that we are always craving. Picking and eating berries at the peak of flavor in the summer is the best. However, it’s uncommon to constantly have access to fruit at its optimal ripeness. As a result, we make adjustments by adding a touch of sweetness, sprinkling a touch of sugar or drizzling a little honey to bring balance. What if there was a seasoning that would allow you to sweeten the fruit with its inherent starch? If it’s not quite ripe, a touch of koji will soften and sweeten it up to be just right. If fruits happen to be on the way out, a purée with koji will yield a sweet porridge that can be spun into a vegan ice cream. Sugar is enjoyable in itself—but the importance of kojifying food goes way beyond that.

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Recommended Reads

Greater Flavor: How to Make A Basic Miso Paste

Koji for a Touch of Sweetness: Koji Sorbet