Soy Milk
What it is
Soy milk is the liquid pressed from ground, cooked soybeans — and in East Asia it is far more than a dairy alternative: fresh soy milk (Chinese doujiang, Japanese tōnyū) is a savory breakfast drink and the raw material from which tofu and silky douhua (tofu pudding) are made.
How it's made
Dried soybeans are soaked, ground with water, cooked, and strained to remove the solid pulp (okara), yielding fresh soy milk. To make tofu or douhua, the hot soy milk is then set with a coagulant — gypsum (calcium sulfate) or nigari (magnesium chloride) — which curdles the soy proteins into curds; lightly set, it becomes the silky pudding douhua, and pressed, it becomes tofu of varying firmness.
Flavor profile
Fresh soy milk is mild, beany, and clean, often drunk savory (with soy sauce, pickles, and fried dough) or sweet. It is far "beanier" and fresher than commercial cartoned soy milk, which is processed to mute the bean flavor and is usually sweetened.
Culinary uses
Drunk fresh (the classic Chinese breakfast of hot doujiang with you tiao — fried dough sticks — sweet or savory), set into douhua topped with syrup or with savory garnishes, and coagulated and pressed into the entire universe of tofu and tofu skins (yuba). It is foundational, not peripheral, to East Asian cooking.
Regional variations
Chinese savory doujiang (with vinegar, soy, chili oil, dried shrimp, fried dough) versus sweet versions; Japanese tōnyū and the rich soy-milk hot pots; regional douhua served sweet (south) or savory (north) in China. Each tradition treats fresh soy milk as a serious ingredient with its own ritual.
Cultural & historical context
Soy milk and tofu have been made in China for many centuries (tofu's invention is traditionally attributed to the Han dynasty), forming a protein backbone for Buddhist vegetarian and everyday cooking across East Asia. Why substitution fails: commercial sweetened cartoned soy milk cannot make tofu (it lacks the protein concentration and is full of additives), cannot replicate the savory breakfast drink, and curdles when it meets acid (the savory doujiang topped with vinegar deliberately begins to curdle into delicate flocs). Dairy milk, of course, will not coagulate into tofu at all.
Reference notes
Tags: `plant-milk`, `soy`, `coagulable`, `tofu-base`, `savory`, `east-asian`. Related ingredients: tofu, douhua, yuba, gypsum, nigari. Related cuisines: Chinese, Japanese, Taiwanese. Suggested links: Douhua, Tofu, Yuba, Coagulants (reference), You Tiao.