The history of sourdough in Alaska, and why long-time residents are called "sourdoughs"

“The Canadian Mounted Police refused to let any of the goldseekers over the boundary at Chilkoot Pass [and into Alaska] without a year’s supply of provisions,” writes Ruth Allman, author of Alaska Sourdough (1976). “A 50-pound sack of flour—and a sourdough pot—would guarantee more satisfactory meals than canned food many times its weight.”

Baking other types of bread would call for eggs, milk, and yeast, which were either hard to acquire or unnecessarily weighty for miners hauling all their supplies over mountain passes. With sourdough, though, prospectors only needed to carry flour and gather water to bake bread, biscuits, pancakes, cookies, and more. And a starter that was maintained and fed with fresh flour could remain viable for lifetimes.

“It’s a survival food in a way,” Costello says. “It’s something you had to take care of so it could take care of you.”