Old-Time Potato Sourdough Starter

This old-fashioned sourdough starter uses potato water to kick-start fermentation, a trick bakers relied on long before commercial yeast existed. The starch in the potato water feeds wild yeast and bacteria from the air, creating a bubbling, tangy starter within a few days.

Use the water left over from boiling potatoes. Let it cool to lukewarm before mixing. Hot water will kill the wild yeast you’re trying to attract, and cold water slows fermentation to a crawl.

Leave the crock or jar uncovered in a warm spot, somewhere around 70-80°F (21-27°C). You want airborne yeast to colonize the mixture. After a few days you’ll see bubbles forming on the surface, and it should smell pleasantly sour, not rotten. Once active, feed it with equal parts flour and water to keep it going.

Kitchen Tips

• Use unbleached flour. Bleached flour has fewer nutrients for the wild yeast and can slow down or stall fermentation entirely.
• Stir the mixture once a day to distribute the developing yeast cultures and introduce fresh air.
• If a dark liquid (called hooch) forms on top, that’s normal. It means the starter is hungry. Just stir it back in and feed.
• Once established, store the starter in the fridge and feed it weekly if you’re not baking regularly.

Variations

• Replace half the all-purpose flour with rye flour for a starter with a more complex, earthy tang.
• Add a teaspoon of honey instead of sugar for a slightly different flavor profile in the finished bread.