Sourdough is made using natural yeast from a bacteria starter culture, which is what gives the bread its characteristic tangy flavor. Sourdough may be trendy now, but this way of leavening bread has been around for millennia, making sourdough one of the oldest types of bread in the world, and its origin seems to stem from North Africa.

The earliest record of sourdough goes back to 1500 BC, when ancient Egyptians mixed wild yeast into their bread, either purposefully or by accident. Many hieroglyphics depict the process of bread making, and bread was reportedly a large part of the Egyptian laborer's diet, along with beer, which may explain sourdough's origin.

It's possible that with all that bread making, some wild yeast made it into a batch, and the ancient civilization was taken by a flavorful end result. Another theory is that, given their obsession with beer, the Egyptians might have ended up mixing flour with the drink, which resulted in a light, airy loaf of bread with some extra yeast.