> And keep some "old dough" for starting the next batch.

It wouldn’t even need to rise. Just heat dough and you’ll have something you can put other food on top of and eat the whole thing.

But also the technique of leavening using natural yeast has been known for thousands of years; it pre-dates the Romans, who definitely used it in their regular bread.

I'd say that running a bakery under those conditions: i.e. would always be yeast around and there is no refrigeration, so for any given dough it's a question of when, not if, a given piece of dough will start to rise.

You will also have a brick in your colon. Not good advice.

Pompeii had snackbars as well. People bought their food on the street.

https://www.theguardian.com/world/2020/dec/26/exceptionally-...

In some districts in Rome, they had large apartment blocks (insualae) several levels high, and fire was forbidden, so people had to buy food on the streets.

From wiki: The insulae could be built up to nine storeys, before Augustus introduced a height limit of about 68 feet. Later, this was reduced further, to about 58 feet

> But not tomatoes yet

Pineapple about same time.