A Brief History of Tofu
Extremely popular in the Orient today, tofu was first used in China over 2,000 years ago. Experts believe that its production began sometime during the Han dynasty, in the second century B.C. According to one Chinese legend, tofu was invented when a cook decided to experiment by flavoring a batch of cooked soybeans with the compound nagari. Instead of flavored soybeans, he wound up with bean curd. Nagari is frequently used in the production of tofu today. From China, tofu was introduced into Korea, and reached Japan in the eight century A.D.
The process by which tofu is made has a lot in common with making cheese. A coagulant is used to curdle soy milk and the curds are then pressed into a solid block. Several types of coagulant are used, from the above-mentioned nagari to calcium sulfate.
To learn more about tofu types and cooking with tofu, see my article "Terrific Tofu."