Some sourdough starters are older than your grandparents. Older than their grandparents. A baker in San Francisco keeps one that's been alive since 1849 — back when people rode horses to California looking for gold. How does a blob of dough stay alive for over a hundred years?

Here's the secret: sourdough starter isn't just dough. It's a tiny city. Millions of wild yeast and bacteria live inside that jar, eating and multiplying every day. As long as you keep feeding them, they never die — they just keep having babies.

Wild yeast are like microscopic Pac-Men. They gobble up the flour and water you add to the jar. As they eat, they burp out carbon dioxide bubbles — that's what makes the starter all foamy and alive-looking. The bacteria help too, making tangy acids that give sourdough its sour flavor.

Every time you feed your starter, you're basically growing a new generation. You scoop out most of the old goop and stir in fresh flour and water. The remaining yeast and bacteria wake up hungry and multiply like crazy. In a few hours, the jar is full of billions of brand-new microbes.

So that 1849 starter isn't actually the same yeast from 1849 — those original cells died long ago. But their great-great-great-great-great-great-grandchildren are still there, living the same life. It's like a family business passed down through ten thousand generations.

If you forget to feed your starter for a week, most of the yeast go dormant or die. But a few tough survivors hide in the goo, waiting. Add flour and water, and they wake right back up and rebuild the whole city. That's how starters survive neglect — they're shockingly hard to kill completely.

Some bakers keep their starter in the fridge, where the cold slows everything down. The yeast just nap between feedings. Others dry their starter into flakes and store it in an envelope — the yeast go into deep freeze mode. Add water months later, and they come back to life.

The starter you feed today will be totally different microbes by next month. But they'll do the same job: eat flour, make bubbles, taste sour. As long as someone keeps feeding them, the chain never breaks. That's how sourdough lives forever — one hungry generation at a time.