Skip the store-bought yeast and craft your own wild yeast starter with just potatoes and water! Perfect for baking soft, moist bread with a mild, sweet flavor.
Peel and boil the potato in 1.5–2 cups of non-chlorinated water until soft (about 20 minutes).
Remove the potato, mash it, but save the cooking water—you’ll need it for the starter.
Step 2: Prepare the Jar
Transfer the mashed potato into a clean glass jar. Pour the reserved cooking water over it until the jar is almost full (leave some space for gas to escape).
Cover the jar with a towel or gauze to keep debris out, but don’t seal it with a lid—the wild yeast from the air needs to be invited in.
Step 3: Wait for Yeast to Develop
Place the jar in a warm spot and wait. After about 24 hours, you’ll start seeing small bubbles forming on the surface. These bubbles are the carbon dioxide produced by the yeast as it feeds on the potato starch.
Step 4: Stir the Culture
Stir the mixture with a clean spoon or shake the jar to redistribute the yeast. Aerating helps yeast thrive over unwanted bacteria. Stir 1–2 times per day.
Step 5: Let It Grow
Wait for another 24–48 hours, continuing to stir occasionally. By now, your starter should be bubbly and have a pleasant, yeasty smell. If it smells foul or rotten, discard and start over.
Step 6: Maintain Your Starter
Once your starter is bubbly and smells good, cover it with a loose lid.
To keep it active, feed it weekly. Discard half of the starter and add either:
More mashed potato and water from a freshly boiled potato, or
A tablespoon of flour or sugar to the original mixture.
Notes
Yeast Development: If you don’t see bubbles after 24 hours, it could be due to cooler temperatures or weak starter. Give it more time or try moving it to a warmer spot.
Feeding Your Starter: When feeding your starter, make sure to discard half of the mixture before adding new potato or flour. This keeps the culture from becoming too large and keeps it active.
Potato Type: Starchy potatoes like Russet are ideal, as they provide the right amount of starch for yeast to feed on.
Long-Term Storage: If freezing or drying your starter, remember that you’ll need to reactivate it with some time and care when you want to use it again.