Tofu is a soft, cheese-like food.
Legend has it that tofu originated in the Western Han Dynasty some 2000 years ago when emperor Liu An ruled the country. He was eager to learn the magical art of immortality, so he went deep into the mountain to refine immortal pills.
Unfortunately, Liu failed in his efforts to produce an immortal elixir. Instead, he accidentally dropped his gypsum into some soy milk, and the result was a new food form which tasted tender and had a light and inviting fragrance of soybeans.
Simple and cheap to produce, the food soon became a favorite delicacy; and was named "bean curd", which is "dofu" in Chinese. So while he failed to find human immortality on his quest way back then, Liu An did instead manage to invent a food that remains to this day. The town where tofu was born, Shouxian County in Anhui province, is today dubbed the "hometown of tofu".
Qi Jing-quan, a native of Shouxian County, still follows the old rules to make tofu.
"It is a tough job. You must get up early in the morning to grind soybeans. It is laborious and time-consuming because we still strictly follow the old rules to make tofu, as the traditional method creates a richer flavor and better texture. We use twin stone grinding wheels, with the larger one grinding the raw soybeans to lightly crush them, and the other fine grinding the beans into soy milk."
It's a pre-dawn start for Qi, preparing the soybeans and peeling off the skins before any cooking takes place. He says that in the modern tofu-making process, the skins are removed from the beans after cooking, or not removed at all, which makes a poor product. Removing the skins before cooking the beans creates a more even texture.
After the raw soybeans are crushed, and the skins are shaken off, the next step is to soak the beans in cold water to soften them slightly. The beans are then finely ground a second time on the smaller stone grinder; and the liquid is strained into creamy, silky soymilk.
"After the second grinding and straining, the soymilk is boiled quickly on a high heat. Then it's turned down low for the milk to simmer for a while; now turn off the heat and cool it until it gets to 90 degrees Celsius. And here is the most important step: to add food-grade gypsum to curdle the liquid."
Once the gypsum is added, the liquid will start to coagulate. This step must be done very carefully—the amount of gypsum must be measured precisely and requires a delicate touch as it's added. Any negligence will make the final result lumpy, foamy or weepy.
With the coagulation done, the material is not yet a firm block of tofu; it's more like a custard-like tofu pudding with some excess liquid. The mixture needs to stay draining for a while in a wooden frame with holes in the bottom. A heavy stone is usually placed on the frame's lid to help squeeze excess liquid out.
Once the tofu has taken a firm rectangular shape, the sides of the frame are removed. Finally the lid is removed and the tofu is done.
It's not just the block of tofu itself that is produced during the tofu-making process. There are many by-products that are as tasty and widely used in cooking as the tofu. Tofu skin is one of them.
As the soy milk is boiled in an open shallow pan, a film or skin forms on the liquid surface. The films are collected and dried into yellowish sheets known as tofu skin. Since it is not produced using a coagulant, tofu skin is not technically a proper tofu; but it does have a similar texture and flavor to some tofu products.
The sheets of tofu skin can be served fresh, dried in a flat form, or bunched up into bundles. Like tofu, the bean curd skin is great for absorbing flavors from a braise or stew; and is therefore a mainstay of the vegetarian diet, though even meat eaters can be tempted by the half-tender, half chewy texture of the product.
Mao Xie-jun has been hand-making tofu skin for decades. Although this bean curd product can be mass produced by machine nowadays, Mao insists doing it in the old way. He says it gives the product a perfectly balanced texture of being tender and chewy at the same time.
"Making tofu skin is a family business that has been going for 300 years. It is not an easy job. You have to stand next to the boiling soy milk to collect the thin veils every five minutes as the cream rises, one sheet at a time. Summer is even more difficult because we can't use air conditioners or fans, as they would spoil the shape and texture of the product. Comparatively speaking, hand-made tofu skin has a much more complex creamy, nutty flavor with a firm bite."
Dou-hua, or tofu pudding, is another soy product widely enjoyed by the Chinese. It's simply soy milk that has been gelled just enough so that it barely holds together. It's delicate, with a creamy melt-in-the-mouth texture.
Tofu pudding has a very mild flavor of its own and as such is compatible with a variety of seasonings. It can be served either hot or cold and comes in both sweet and savory forms. In northern China, douhua is often eaten with soy sauce, so you'd get a savory flavor. In south China, it typically goes with a sweet topping made of sugar syrup, peanuts and different beans, and jellies.