Bon Appétit Test Kitchen Manager Brad Leone is back for Episode 26 of "It's Alive," and this time he's tackling the fermentation classic: sourdough bread. Brad is joined by Bon Appétit's own Claire Saffitz, Senior Food Editor and baker extraordinaire to guide him on this journey.

Bon Appétit’s Brad and Claire are back for a very special crossover episode (Part 1!) of It’s Alive. Claire says they’re making doughnuts with sourdough starter. Brad’s trying to make “sourdoughnuts” a thing. Who will win? You will: this episode had so many good Brad and Claire moments that we had to make it two parts.

*Correction, let's make that three parts.

Brad Leone and Claire Saffitz are back to finish what they started. Sourdoughnuts Part II. Watch it all go wrong and get ready for the final installment of the Sourdoughnuts saga.

Brad Leone and Claire Saffitz return for the final installment of It’s Alive: Sourdoughnuts. This time… they actually make doughnuts. Watch as they conclude their long and winding journey towards light and pillowy sourdough doughnuts. Be sure to check out the previous episodes if you missed them! Long live the Rat King.