- Clean soybeans by removing dirt and the damaged soybeans. Pour into a large deep pot filled with 1600 millimetres tap water (usually 3 or 4 times of the dry soybean by weight) and leave the soybeans to soak overnight at room temperature. Drain and rinse soaked beans again with tap water. Dehull the beans and the weight should gained twice, i.e. about 800 grams. Bring 2 liters of water to a boil. Add in baking soda, then the dehulled soya beans into the boiling water. Blanch for 8-10 minutes. Drain and rinse with hot water. Grind the blanched soybeans with 3 liters of water (in general, the ratio of water for grinding is 7-10 times of the dry bean by weight) in 2-3 batches into slurry in a blender for 3 minutes at high speed. Filter through a colander lined with cheesecloth to remove soya fiber-okara and to collect about 3 liters of soya milk.
- Divide the soya milk into two 3-liter deep pot and set them over medium heat and bring the whole mass to a boil. It will foam up while heating the mixture, skim it off with a ladle. Adjust the heat to low, continue to cook about 10 more minutes. As soya milk cooks, dissolve 15 grams of gypsum-calcium sulfate (the amount of coagulant used is 0.3-0.5% of cooked soymilk by weight) in half cup of warm water.
- Turn off the heat, but leave the pots on the glass tops to keep it hot. To be precise, the temperature should reach 95C/200F (with Nigari, the temperature should low down to 75C/160F). At this point, slowly pour in the gypsum solution in a few additions, stirring gently in one direction. Immediately stop stirring as the curd begins to form. Allow the curd to set without disturbing for 10-15 minutes.
- Now the chunks of forming curds stay at the bottom and yellowish liquid on the top. If there are still some milky areas after adding all the solution, mix additional one teaspoon of powder and two tablespoons of warm water. Gradually add in until no more white particles float. Transfer the curds into a tofu box lined with cheesecloth. Any container that has many small holes to allow residual liquid to drain can serve as a tofu mold. Fold cloth, cover with tofu lid and press with a heavy object, such as a pot of water, and allowed to sit for15 minutes or so. Remove tofu lid, unfold the cloth and remove the tofu. Place tofu in water and chill until needed.
- When making soya milk from JOYOUNG automaton, follow instructions as per user's manual. Add the soaked soya beans to the cup of the soya maker, then pour in water between the water level marks. Lock the head attached with cylinder in position. Plug in and press the START button. That’s all. Pour all the batches of soya milk into a large pot and simmer for about 10 minutes. Cool down to 95C/200F if using gypsum, and 75C/160F with nigari.