Nigari is a coagulant that can be used to make tofu.
Making tofu is quite simple. The general idea is, you want to make soy milk, curdle the soy milk, then press the curds together. The most time consuming part is stirring the pot when cooking the soy milk and trying to squeeze out every last drop of soy milk!
Homemade Soy Milk and Tofu Recipe:
1. Soak ~2 cups of raw soybeans overnight.
2. Drain soybeans.
3. Blend soybeans with water until smooth. 1 cup soaked soybeans to 3 cups water.
4. In a large pot, bring the puree to a boil. Simmer for 15 mins stirring constantly. Keep a close eye on the pot as it can easily boil over. Skim foam.
5. Strain the puree over a bowl using a nut milk bag or cheese cloth. Pulp = okara. Liquid = soy milk.
You can stop here if you only want fresh soy milk. I reserved a cup for drinking. The pulp (okara) can be discarded or saved to use in other recipes such as okara seitan.
7. Heat soy milk until 160F, stirring. Turn off heat.
6. Make coagulant. Mix 1 tbsp nigari flakes into 1/2 cup water.
6. Pour in the coagulant. Gently stir to incorporate. Cover pot and let sit for 10 mins for soy milk to curdle. It's ready when the curds separate from the liquid which should be clear and slightly yellow. The liquid should not be milky. If milky, add more coagulant.
7. Strain out curds into a colander lined with a tea towel or cheese cloth.
8. Wrap the curds into a block shape.
9. Press out liquid for 20 min (less time for softer tofu). I didn't have a tofu press so I used a steamer pot for drainage and put a heavy weight on top of the block.
10. Store tofu in cold water. This helps firm up the tofu and keep it fresh. Change this water daily to prolong freshness.