I’ve noticed that day old focaccia bread has white stains where salt was sprinkled on top after coming out of the oven, why is that? Does it have something to do with the chloride present in table salt?
When the bread first comes out of the oven, it’s generating steam that dissolves some of the salt. When the water evaporates, the salt is left behind in the white patterns.
There’s no bleaching going on, if that’s what you’re thinking.
Nitpick: the salt on focaccia is usually added *before *baking.