Potato Sourdough Starter

Potato Sourdough Starter


  • A 2 gallon safe plastic or glass container, about a 7 ½ liter capacity, well cleaned
  • A large rubber band
  • Plastic wrap


  • 1 medium potato unpeeled and cubed
  • 3 ½ cups 28 fluid ounces water
  • Unbleached bread flour
  • 1 teaspoon 6 grams granulated sugar


  • Bring water and cubed potato to a boil in a saucepan for about 12-15 minutes, or until the potato chunks are fork-tender. Allow the mixture to cool to about 78 degrees Fahrenheit (about 25 degrees Celsius).
  • Measure out 2 cups (16 fluid ounces or 480 ml) of the potato water, saving the potato for another use. Discard the remaining water.
  • In the 2 gallon container, mix together the 2 cups of potato water, 1 ¾ cups (8 ¾ ounces or 250 grams) bread flour, and granulated sugar. Use a wooden spoon and blend well.
  • Cover the container with plastic wrap and secure with a large rubber band. Let it sit out at cool room temperature, about 70-75 degrees Fahrenheit (21-24 degrees Celsius) for 24 hours.
  • Stir the starter once every day, and allow it to sit for 3 more days.
  • On day 4, the starter may begin to separate. Feed the starter by stirring in 1 ¼ cups (9 ounces or 255 grams) bread flour and 2 cups (16 fluid ounces or 480 ml) of 78 degrees Fahrenheit (25 degrees Celsius) water.
  • Cover the starter with the plastic wrap and rubber band, and allow it to sit for 4 more days (to day 8) at cool room temperature. Do not stir.
  • On day 9, begin a regular feeding schedule of 3 feedings per day approximately every 4-6 hours. The feedings should consist of 1 cup (8 fluid ounces, 240 ml) cool 78 degrees Fahrenheit (25 degrees Celsius) water and 1 ¼ cup (6 ounces or 185 grams) bread flour. Feed the starter first thing in the morning, the second feed at about mid-day, and the third before you go to bed.
  • Feed the starter for 3 more days, through day 11.
  • On day 12, you can begin baking with your starter.


NOTE – if you want to limit the amount of starter you are producing, before the first feed of the day, discard all but 2 cups of the starter, wash out your container, begin the day’s feedings with the remaining 2 cups.
NOTE – after you have used a portion of your starter in a recipe, remember to save 2 cups of the starter and place it in a smaller, air-tight container, dated and labeled, and placed in the refrigerator for 2-4 months.