Tofu is fermented in the shade for three days, and the tin foil is opened once a day to change the air. There will be mucus on tofu in three days. If the temperature is high enough, there will be yellow hair, indicating that the fermentation is successful.
When making stinky tofu, merchants usually ferment stinky tofu first, then make tofu embryos, and finally soak the tofu embryos in the fermented stinky tofu.