Soak beans overnight
To make 6 appetizer-sized servings, rinse and soak one cup of dried soybeans for 8 to 10 hours in plenty of water.
Rinse the beans thoroughly, drain them, and put them in a food processor or blender with one cup of water. Puree them well, scraping down the sides as necessary, for about three minutes, until you have something that looks kind of like a bean dip.
Transfer the soybean puree into a large pot and stir in 2 cups of water. Heat the mixture over medium-high. Scrape the bottom and sides of the pot with a wooden spoon or heatproof spatula to make sure it doesn’t scald. When the foam rises and the mixture just begins to boil, turn off the heat.
Pour into lined strainer
Have a large bowl ready with a strainer or colander set into it. Line the strainer with a flour sack or large tea towel, something strong but not too thick. It should allow the soy milk to pass through without letting out any of the soybean pulp. Make sure the towel has plenty of overhang so that you’ll be able to bring up the sides and keep the scaldingly hot soybeans well-contained. Even a strong pillow case that you are not particularly fond of might do the trick.
Pour the hot soybean mixture into the lined strainer and wash out your cooking pot.
Twist, squeeze, press. Do whatever you need to get the soy milk out. The Book of Tofu suggests using the bottom of a sturdy glass bottle. I used a pestle or the pusher from a food processor. But my favorite way to squeeze out the milk was to use my hand, protected with a silicone oven mitt.
After a few minutes, you should be left with mostly just the soybean pulp, or okara.
Get every last drop
Open up the liner and pour 1⁄2 cup water over the okara. Wrap it all up again and squeeze out the last drops of soy milk. You should end up with about 3 1⁄4 cups of raw soy milk and about 1 cup of okara. (The okara can be saved and cooked further for a number of dishes.)
Cook the soy milk
The final step in preparing the soy milk is to cook it. Bring it to a boil over medium-high, then reduce the heat to medium-low. Simmer the milk gently for about 7 minutes, until the milk has lost its raw bean taste. Skim the foam off the surface as necessary.
You’ve made soy milk! You can stop here and just enjoy it without even thinking about making tofu.
But you’ve already done the hard part. Might as well go all the way. Cool the milk in a cold water bath. Transfer it to the fridge if you want to finish the tofu-making process later, within the next day. Or, move on to the next step.
There are many types of tofu coagulants out there. The easiest one to find may already be in your home: Epsom salt. Less common, but available at Japanese markets, some health food stores, and, of course, Amazon, is powdered nigari—magnesium chloride. The magnesium chloride makes a subtly sweeter and nuttier tofu than the more neutral and very mildly chalky Epsom salt, but the difference is slight. Dissolve 1⁄2 teaspoon of either one in 2 tablespoons of water.
Add the coagulant solution to the chilled soy milk as you move a spoon through the milk with a gentle plunging motion. Gently distribute the mixture among small heat proof dishes (about 1⁄2 cup each).
Heat gently in a simmering bath
Carefully transfer the filled dishes to a pan set on the stove. Fill the pan with enough simmering water to reach the top level of the soy milk mixture.
Cover the pan with a clean dish towel (to absorb the steam) and lid, folding up the ends of the towel over the lid so you don’t start a fire. Simmer gently for about 10 minutes or until the tofu jiggles like barely set custard. Transfer the tofu to the counter to continue to set at room temperature for several minutes.
Serve warm or chilled in their individual bowls. Or, invert each bowl and release the tofu onto a small serving dish. It’ll look just like panna cotta.
Try these simple garnishes over cold kinugoshi for summer refreshment:
Lemon zest, finely chopped cucumber, and sea salt flakes.
Dried bonito flakes (katsuoboshi) and ponzu sauce.
Ginger, scallion and soy sauce.