Gypsum vs nigari vs GDL, and texture - calcium sulfate gives silken tofu pudding, nigari gives a tofu-pudding-water.
Enter soy milk volume, pick coagulant, texture, and target temperature. The card gives coagulant in grams, target temp, and rest time.
Gypsum, nigari, and GDL produce different tofu puddings. Gypsum is the southern Chinese standard (sweet, custardy). Nigari is the Japanese standard (slightly bitter, saltier). Most recipes use one name without explaining the difference.
Anyone making tofu pudding for the first time. People trying to replicate a specific shop's version. Cooks wanting silken texture who keep getting rubbery.
The art is in the stir. Pour coagulant in a stream, then stop. Any stirring after that breaks the curds and produces grainy pudding. GDL is unique - it sets slowly over 45 minutes, so the wait is longer. Nigari sets fast (15 min) but tastes more bitter.
Soy milk protein concentration matters. Home-made soy milk is typically 3% protein; commercial is 3.5%. Numbers assume 3.5%. If you make thinner soy milk, increase coagulant by ~15%.
Why grainy? Stirred after coagulant, or soy milk was boiling.
Why didn't it set? Soy milk not hot enough (target temp matters).
Can I combine coagulants? Yes - gypsum + nigari 50/50 is common for slightly firmer silken.