Leaven (sourdough) has been highly valued by communities throughout history, proven by the food riots of 1801 and its astronomical price tag during the French revolution (usually up to 88% of the working classes’ daily income).

Even since the 3^rd century in Rome, legislation laid out standards for the distribution of grain and bread, “For every modius (6.5-7kg) of grain, the bakers must return twenty-four pounds of bread of the first quality.” These laws were exacting, and the punishments for breaking them were harsh: bakers could be forced to pay quadruple of what the illegal product was worth, and it would be confiscated too. If their wrongdoing was deemed too severe, and caused famine, the baker(s) could have been fined, flogged publicly or be forced into labour.

In writings of Pliny the Elder, long before the roman legislation, he talks about the use of barm (the beer foam that is developed when brewing, it has a high content of yeast) to make bread, this was used in areas where communities had access to a brewery.

But during voyage of sailors, and the discovery of the new world, leaven was the item used. It was easy to preserve, you just needed to tear off a chunk of a raw bread loaf and cover it in salt, it developed a hard shell that could be cut off before having the innards diced and soaked in water. This cycle could be repeated many times and was the lifeline for the colonies in America; wheat was scarce, so a constantly active leaven was hard to produce.