China, introduced to Japan in 7th century — fully naturalised and refined in Japan
Traditional Japanese tofu production begins with dried soybeans soaked overnight, ground into 'go' (soy slurry), cooked to extract soymilk, then coagulated with nigari (bittern — magnesium chloride from sea salt production) or gypsum (calcium sulfate) to form curds, which are then pressed (or not) into the final product. Silken tofu (kinugoshi): soymilk coagulated directly in the serving vessel without pressing — the curd sets as one unbroken mass of custard-like texture. Cotton/firm tofu (momen): curds broken and pressed under weight to expel whey — denser, more protein-concentrated, more robust. The coagulant choice matters: nigari produces a more complex, slightly mineral flavour and softer curd; gypsum produces a smoother, more neutral curd with firmer set. Regional tofu specialities include Kyoto's extremely delicate silken tofu (served raw with just dashi and soy), Okinawa's shimadofu (very firm, almost feta-like, coagulated with sea salt), and Koya-dofu (freeze-dried tofu — a Buddhist mountain speciality).
Fresh tofu has delicate, sweet soy milk flavour with clean finish; nigari tofu has slight mineral-sea complexity; quality degrades rapidly — freshness is paramount
Soymilk concentration determines final tofu richness — higher concentration = richer, denser tofu; coagulant temperature is critical: nigari added to soymilk at 75–80°C produces optimal curd formation; gentle handling of curds after coagulation preserves texture; pressing time and weight determines final density from silken to extra-firm; fresh tofu has a short shelf life (2–3 days) — the sweetness of fresh soy is perishable.
Home tofu with standard nigari: heat soymilk to 78°C, dissolve nigari (4g per 1L soymilk) in 100ml warm water, pour over soymilk in a circular motion, cover and do not disturb for 10 minutes; Kyoto yudofu (tofu simmered in kombu water) is the purest expression of premium silken tofu — the flavour is in the tofu itself, not the accompaniments; fresh tofu from a specialist tofu shop (tofu-ya) eaten within hours of production is a revelation compared to supermarket tofu.
Adding nigari to soymilk that is too hot (above 90°C) or too cold (below 70°C) — both produce poor curd formation; over-stirring after coagulant addition (breaks the forming curd structure); pressing too aggressively (produces mealy, crumbly tofu rather than firm-yet-smooth); serving fresh tofu at refrigerator temperature (the subtle sweet-soy flavour is best appreciated at room or slightly below room temperature).
Japanese Cooking: A Simple Art — Shizuo Tsuji