1 cup flour
½ cup lukewarm filtered water
1 tsp. dry yeast

  • Mix all ingredients in a 1-quart mason jar (flour and water should be equal by weight), adding water if needed to make a thick paste.
  • Cover with a wet towel, and rest for 24 hours at room temperature.
  • Feed the starter, and continue feeding weekly.
  • Refrigerate when not feeding and using.

Feeding and Using

  • Discard all but ½ cup of the starter. It will contain less-active yeast, and can be used to make baked good that do not need to rise.
  • Add 1 cup of flour and 1/2 cup lukewarm filtered water.
  • Mix thoroughly and let rest 4-10 hours at room temperature, until risen and starting to fall.
  • Use a chunk of starter to make sourdough bread.

Source: https://www.feastingathome.com/sourdough-starter/