Create a DIY starter from scratch with rye flour

Build a sourdough starter from nothing but flour and water in about 7-14 days. Rye flour is the best starting flour because it contains more free sugars, higher enzyme activity, and more nutrients for wild yeast and bacteria to thrive.

Steps

1. Day 1 — Mix: Combine 100g whole rye flour and 125g filtered water (78-80F) in a clean glass jar. Stir vigorously, cover loosely, and mark the level with a rubber band.
2. Day 2 — Wait: Little to no activity is normal. Do not feed. Let it rest another 24 hours.
3. Day 3 — First feed: Discard all but 75g. Add 50g rye flour, 50g all-purpose flour, and 100g water. Stir well and cover.
4. Days 4-6 — Twice daily feeds: Discard to 75g every 12 hours. Feed with 50g rye, 50g all-purpose, and 100g water each time. Activity may dip on Day 4-5 — this is normal as beneficial bacteria replace the initial Leuconostoc.
5. Days 7-14 — Build strength: Switch to a 1:5:5 ratio — discard to 20g, add 50g flour blend and 100g water. Continue twice daily until the starter reliably doubles in 6-8 hours.

Tips

• Use filtered or dechlorinated water — chlorine inhibits beneficial bacteria
• Keep the jar in a warm spot, ideally 75-80F. Below 70F, fermentation slows dramatically
• A digital kitchen scale is essential — volume measurements are too inconsistent for starter feeding
• The starter is ready when it doubles predictably, has bubbles throughout, a domed top at peak, and smells pleasantly tangy
• Any fuzzy mold (pink, orange, blue, green) means discard everything and start over