As it turns out, there is no secret process of industrial machinery and mysterious chemicals in between soymilk and tofu. Unlike the process that transforms milk into yogurt, soymilk doesn’t need heat or probiotics to turn it into tofu. The sole ingredient is tofu coagulant.
Tofu coagulants are stirred into soymilk to coagulate, or solidify it, into tofu. You can use your own, homemade soymilk with our tofu box and a little coagulant to make natural, additive-free tofu.
Andrea Nguyen from Viet World Kitchen recommends nigari and gypsum over Epsom salts. While Epsom salts, lemon juice, and vinegar will coagulate soymilk, the taste of the resulting tofu is inferior. Epsom salts in particular are often described as creating a nail polish remover or battery fluid taste. Lemon and vinegar make for lemony and vinegary tofu.
In Ms. Nguyen’s Tofu Coagulant Guide, she writes that she sticks to Sanlinx nigari and gypsum, and describes experiences with unreliable coagulants from both Asian and American markets.
Ms. Nguyen is an author, teacher, and consultant. She has appeared on NPR’s Splendid Table, written for Wall Street Journal and Bon Appetit, and taught at the Institute for Culinary Education in New York, to name a few. She blogs at Viet World Kitchen.