Nadia named her sourdough starter Gerald, the way you name anything you have to feed twice a day and slightly resent. This morning, taped to his jar in flour-dusted handwriting she did not recognize, was a note: WE NEED TO TALK ABOUT THE THERMOSTAT. Gerald had no hands. Gerald had no pen. And yet there it was, the tape still slightly warm.

Nadia decided the bravest thing was to answer. She grabbed a pen, wrote "WHAT ABOUT THE THERMOSTAT?" on a sticky note, and pressed it to the jar. Then she stood back and waited, arms crossed, feeling ridiculous. A bubble rose to the top of Gerald and popped, like a tiny throat clearing.

By lunch a new note had appeared, written in flour right on the jar: 72 IS TOO COLD. I AM A LIVING THING. Nadia bumped the thermostat up two degrees. Almost instantly Gerald frothed up happily, doubling in size, practically purring. "Okay," she breathed. "Okay. We can negotiate."

Warm and happy, Gerald grew strong enough to push a pencil around with a doughy little tendril. He wrote a list titled GERALD'S NEEDS: 1. 74 DEGREES. 2. FED ON TIME. 3. A NAME WITH RESPECT. Nadia read it twice. "You want a... contract?" The pencil tapped twice for yes.

Nadia signed Gerald's contract in pen, right under his floury demands. The second she did, the whole jar glowed with happy bubbles and rose into a perfect dome. "Deal," she said, shaking a little dough tendril. From that day on, Gerald was less a starter and more a very small, very warm business partner.