Soy sauce, which is Chinese in origin, is made from a fermented paste of soybeans, roasted grains, brine and a mold called kōji. Soybeans are soaked and cooked, and wheat is roasted and crushed. The mixture is inoculated with kōji, mixed with brine and left to brew. The liquid is pressed from the solids, then it’s pasteurized and bottled. The final product is thinner and saltier than tamari, and it contains wheat.
What is tamari?
Tamari, on the other hand, is a Japanese ingredient, and it’s actually a by-product of making miso (a type of fermented soybean paste). When the fermented soybeans are pressed, the leftover liquid becomes tamari. And since grain isn’t usually added, tamari is often gluten-free by nature (but double-check the label to be absolutely sure). It’s also thicker and less salty than soy sauce, but with a similar umami flavor profile.