Those of you who’ve never had a real sourdough have never had real bread. Good food fights back a little when you eat it, and a proper sourdough, with its crispy crust and tangy center, certainly fits ...

For fermentation revivalist Sandor Katz, making sourdough, kimchi, and kombucha is about more than eating well at home. It’s a metaphor for creative systemic change, bubbling away from the ground up.