Yes, the core formula is deceptively simple. Soy sauce is built from just four ingredients: soybeans, wheat, salt, and water. That’s it. But the magic? The magic is in the mold.
Wait, don’t close the tab! I know “mold” sounds gross, but it’s the friendly kind—specifically, a fungus called Aspergillus oryzae (also known as koji). This little powerhouse is the unsung hero of Asian cuisine.
The Koji Life: A Funky Fermentation Party
First, the soybeans get steamed until they’re soft, and the wheat gets roasted and crushed. Why wheat? For sweetness and depth. The soybeans bring the umami, the wheat brings the body. Think of them as the yin and yang of sauce.
Then, you sprinkle koji spores all over the mixture. Over the next couple of days, the mold feasts on the starch in the wheat and the protein in the soybeans. It’s basically a microscopic rave, and you’re the host.
Side comment: If you ever tell someone you’re “growing mold for dinner,” you’ll get some funny looks. But that’s exactly what ancient brewers did, and it’s genius.
