I have started growing sourdough starter. It would usually take 7 days to complete.
Today is day 4. It smells like stinking tofu now, which is normal at this stage. Instead of discarding half of the starter, I saved it to make flatbread to see if it would taste like stinking tofu.
I added cornmeal, olive, and salt to make a dough and roll it flat, then cook it on a cast iron skillet.
To my surprise, it smells like cheese when it is heated up.
The taste is a mix of stinking tofu and cheese.
In summary, the smell of stinking tofu, cheese, sourdough in progress are all from fermented food.