Japan — tofu introduced from China 8th century; Japanese refined technique and developed specific coagulant varieties and textures over centuries
Tofu making requires precise understanding of the coagulation process — hot soy milk (tonyu) is treated with a coagulant that causes the soy proteins (primarily glycinin and beta-conglycinin) to form a gel network. The traditional coagulant is nigari (苦汁, bitter water) — magnesium chloride extracted from seawater during salt production. Different coagulants produce different tofu textures: nigari creates irregular curds with slightly mineral character (traditional flavor); calcium sulfate (石膏, sekko) creates finer, smoother, whiter tofu (the standard silken variety). The temperature of soy milk at coagulation (75-85°C) and stirring technique determine curd size and final texture.
Pure soybean protein with subtle mineral character from nigari — fresh tofu has delicate sweetness that deteriorates within hours of making
{"Nigari concentration: 0.3-0.5% of soy milk weight — too much creates bitter tofu; too little doesn't set","Temperature: add nigari at 70-75°C — above 85°C coagulates too quickly, below 65°C too slowly","Stirring technique: add nigari in three stages, stir gently then stop — motion affects curd size","Momen tofu (cotton tofu): ladled into cloth-lined mold, pressed — firmer, more water released","Kinugoshi (silk) tofu: poured into mold without pressing — silken, delicate texture","Setting time: let stand undisturbed 10-15 minutes after coagulation for full gel formation"}
{"Sea water nigari: fresh sea water as natural nigari — some Kyushu and coastal tofu makers use directly","Yudofu preparation: add freshly made momen tofu to cold kombu dashi, heat slowly — never boil, serve in pot","Agedashi tofu: silken tofu coated in thin katakuriko, fried until just golden — served in dashi broth","Homemade nigari tofu: obtainable at health food stores; simple 4-step home process for fresh tofu","Oboro tofu: soft, unpressed tofu served in whey (cooking liquid) — the freshest possible tofu experience"}
{"Stirring after adding all nigari — breaks the forming gel network; gentle initial stir then absolute stillness","Temperature too high — fine-grained, crumbly tofu results from over-rapid coagulation","Wrong soy milk concentration — tofu requires full-fat soy milk (not reduced fat versions for drinking)"}
Tofu Science and Making — Japanese Tofu Association; Soy Product Culture Japan; Traditional Tofu documentation