I bought a sourdough starter from a woman named Deb off Craigslist in 2019 for eight dollars. She met me in a Trader Joe's parking lot in Glendale and handed it over in a mason jar with a rubber band around a piece of parchment. It smelled like green apples and paint thinner. She said it had been going since 1994.

The starter is now dead. I killed it in the second week of the pandemic by feeding it bread flour I'd panic-bought that turned out to be self-rising. Self-rising flour has baking powder and salt in it. Salt, in quantity, murders the yeast. I did not know this. Nobody tells you this.

This post is about what I learned rebuilding a starter from scratch, twice, and why almost every recipe you'll find online is subtly wrong about hydration ratios. If you just want the schedule, skip to the part with the table. But the ratios are where people go wrong, and the ratios are boring, which is exactly why they don't get explained.
