Assembly Line

How tofu is made

Tofu is made like cheese, with soy milk curdled by a mineral and pressed into blocks.

stations
7
things upstream
3
raw sources
3
step from the ground
1

The short version

Soybeans are soaked, ground with water and cooked into soy milk. Filtering removes the pulp, and a coagulant such as calcium sulfate, nigari or glucono delta-lactone is stirred in so the proteins gel into curd. The curds are pressed in molds to drain the whey. The firmness depends on how much liquid is squeezed out.

  1. Soak the beans

    Dried soybeans swell in water for hours until they are plump. Soft beans grind to a smoother slurry.

  2. Grind with water

    The soaked beans are ground with fresh water into a thick slurry. Grinding breaks the cells open and releases protein and oil.

  3. Boil the slurry

    Steam cooks the slurry. Heat deactivates compounds in raw soy that interfere with digestion, and it prepares the proteins to gel.

  4. Strain out the pulp

    A filter press or centrifuge separates the liquid soy milk from the fibrous pulp, called okara. The pulp is used in feed or other foods.

  5. Curdle with a coagulant

    Calcium sulfate, magnesium chloride (nigari), glucono delta-lactone or an edible acid is stirred into hot soy milk. Calcium and magnesium ions link the soy proteins into a gel. The choice of coagulant sets the texture, with gypsum giving tender but slightly brittle tofu and GDL giving silken tofu.

    Goes in
  6. Press into blocks

    The curd is broken up, ladled into cloth-lined molds and pressed so whey runs out. Pressing longer makes firm and extra-firm tofu, while silken tofu is left to set unpressed in its package.

  7. Cut, chill and pack

    Blocks are cut to size, cooled in clean water, packed in tubs with water and often pasteurized.

End of the lineTofu

Worth repeating

  • Chinese legend credits tofu to Prince Liu An, who lived from 179 to 122 BC.
  • Benjamin Franklin mentioned tofu in a 1770 letter, calling it cheese from China.
  • Before refrigeration, tofu in China was usually sold only in winter.

Back to the ground

Follow every input upstream and tofu starts as these 3 raw sources.

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Sources

Cite this page: "How tofu is made." Assembly Line, 2026-11-03. https://assemblyline.org/make/tofu

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