Tōfu-Making — From Soymilk to Firm and Silken

Overview

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).

Flavour Context

Fresh tofu has delicate, sweet soy milk flavour with clean finish; nigari tofu has slight mineral-sea complexity; quality degrades rapidly — freshness is paramount

Key Principles

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.

Pro Tips

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.

Common Mistakes

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).

Source

Japanese Cooking: A Simple Art — Shizuo Tsuji

Cross-Cuisine Parallels

• Chinese tofu production preceded Japanese by centuries — Japan learned from China, then refined the technique toward greater delicacy and variety of textural range → Doufu production, mapo tofu Chinese
• Tofu and fresh cheese share the same fundamental process: protein-rich liquid coagulated by acid or mineral coagulant and pressed — different proteins (soy vs dairy) identical technique → Fresh cheese (ricotta, paneer) making European