Beer is so old that we don’t know how old it is.

Most of the earliest known cultures brewed it, and some scholars believe that it was the quest for beer, not bread, that motivated our hunter-gatherer ancestors to settle down and cultivate grain.

The first beer probably came from Africa, because that’s where the first people were, said Patrick McGovern, a biomolecular archaeologist at the Penn Museum and a longtime authority on ancient fermented beverages.

Beer is basically fermented grain. First, moisture makes the grain sprout, priming its enzymes to transform starch into sugar. Yeast then converts the sugar into alcohol.

Humans would have discovered this process by happy accident, probably in many places around the world at different times: A pile of grain sat out in the rain and sun, some wild yeast latched onto its sugar, and a few days later — whoa! They learned to replicate the process, creating beer traditions nearly everywhere.