Whole-Wheat Sourdough Starter

Ingredients

• 4 1/3 cups whole-wheat flour (1 pound, 6 ounces), divided, plus more as needed for feeding
• 2 1/2 cups warm water (85 degrees F), divided, plus more as needed for feeding
• 2/3 cup plus 2 tablespoons all-purpose flour (4 ounces), divided, plus more as needed for feeding

Instructions

1. Day 1: Combine 3/4 cup plus 2 tablespoons whole-wheat flour and 1/2 cup of water in a 2-quart plastic or glass container. Do not use a metal container. Stir until the flour and water are well mixed. No dry flour should remain. Cover the container with plastic wrap or a loose-fitting lid. If you are using a glass jar, do not tighten the lid. Expanding gasses can break the glass. Let the mixture sit for 24 hours in a warm place, 75-90 degrees F. If the temperature is lower, the starter may take a few days longer to fully develop.
2. Day 2: Discard half the starter, leaving 4 ounces in the container. Add 3/4 cup plus 2 tablespoons whole-wheat flour and 1/2 cup of water. Stir well and cover loosely. Let the starter sit for 24 hours. Near the end of day 2, the mixture should have expanded a little and some small bubbles should have appeared.
3. Day 3: Repeat the feeding process from Step 2, discarding half the starter and adding 3/4 cup plus 2 tablespoons whole-wheat flour and 1/2 cup of water.
4. Day 4: The starter should have expanded and should have a distinct, sour odor. More bubbles should be visible on top. Begin a 12-hour feeding schedule: In the morning, repeat the feeding process from Step 2, discarding half the starter and adding 3/4 cup plus 2 tablespoons whole-wheat flour and 1/2 cup of water. Repeat the feeding process again 12 hours later.
5. Day 5: The starter should have a ripe, sour odor. Small bubbles should be abundant throughout the mixture. Discard half the starter, leaving 4 ounces in the container. This time, feed with 1/3 cup plus 1 tablespoon whole-wheat flour and 1/3 cup plus 1 tablespoon all-purpose flour and 1/2 cup water. Continue the 12-hour feeding schedule, discarding half the starter and using 1/3 cup plus 1 tablespoon whole-wheat flour and 1/3 cup plus 1 tablespoon all-purpose flour and 1/2 cup water for each feed until you are ready to bake. Or, store the starter in the refrigerator and feed once per week.