How can a sourdough starter be 100 years old?

Question

I keep seeing sourdough starters all over socials. How can sourdough starters be many years old. Don’t you need to use the starter to make the bread? ELI5!

In: Other

Answer 1

A sourdough starter is a live culture of specifically chosen yeasts and bacteria on a growth medium. You use some of the starter to make the bread, and then give it more food to let it grow. Think of a fire that you can use to light a bunch of torches.