5 cups Soy Milk, at room temperature
2½ teaspoons packed gypsum, or 1½ teaspoons packed gypsum plus 1½ teaspoons tapioca starch
¼ cup water, filtered or spring preferred
Put the soy milk in a medium saucepan.
Over medium-high heat, bring to a boil, stirring often with a wooden spoon to prevent scorching and keep a skin from forming.
Meanwhile, choose a larger pot, such as a deep 4-quart pot, to hold the finished tofu. In the pot, whisk together the gypsum and water to create a milky liquid. Position the pot somewhere low enough so you can pour the soy milk into it from about 12 inches above. Place the pot on a dishtowel to minimize mess from any splashing.
When the soy milk reaches a rolling boil, turn the heat off. Whisk the coagulant because the solids tend to settle. Holding the saucepan about 12 inches above the pot, pour the hot soy milk into the coagulant; the intentional turbulence will mix the ingredients together. Works best if you start low and raise the saucepan higher as you pour. Cover immediately with a lid and move the pot if necessary. Let the tofu sit, undisturbed, for 15 minutes.
The tofu can be used once it has set. However, let it sit for another 30 minutes and the flavor will have developed further. Check recipes for information on using the tofu. If there are a lot of residual bubbles on the surface of the set tofu, use a spoon to gently remove them. Once you scoop the tofu, you break it up and it begins releasing whey. That is its nature. The longer it sits, the more it will drain, just like regular tofu. Use a slotted spoon to scoop if you want to leave some of the whey behind. To minimize the amount of whey that seeps out, scoop large pieces of the tofu and do it right before serving as savory or sweet tofu pudding.
Store the tofu pudding for up to 3 days, replace the lid on the pot and refrigerate after the tofu has completely cooled. When reheating for warm tofu dishes, gently pour water into the pot around the tofu’s edges (to avoid breaking it up) to cover by ¼ inch. Heat over medium-low heat until the tofu is warm to the touch. Avoid boiling because that may break up the tofu or make it unpleasantly firm. To keep the tofu warm, use the lowest heat.