Sourdough Starter Guide

The Theory: 3 Stages

1. The Capture Stage (Days 1-3): Creating a medium for wild yeast and bacteria to thrive. You use whole grain rye flour because it contains more fermentable nutrients since the bran and germ haven't been stripped away.

2. The Cultivate Stage (Days 3-6): Methodically building up that specific population of wild yeast and bacteria through a process of natural selection. By feeding it on a 24-hour schedule, you encourage the good microbes to outcompete molds and bad bacteria.

3. The Maintenance Stage (Day 6 onwards): Sustaining the healthy population of yeast and bacteria with consistent daily feedings of fresh starchy carbohydrates (flour) for as long as you want to keep the starter alive.

The Ingredients & Tools

Whole Grain Rye Flour: Used in the beginning to kickstart fermentation.
All-Purpose Flour: Unbleached (like King Arthur) for later feedings and maintenance.
Water (1 Quart): Preferably filtered. Leave it sitting out in a container starting on Day 1 to dechlorinate it and bring it to room temperature.
Digital Gram Scale: For precise measuring.
A Container: A 12-16 oz glass jar or deli container with a loose-fitting lid.

Stage 1: Capture

Day 1

In your jar, measure 150g room temperature (dechlorinated) water and 100g whole grain rye flour. Stir vigorously to combine. It will look very wet (150% hydration), which is deliberate because yeast and bacteria thrive in tepid, wet conditions. Put the lid on loosely and let it sit at room temperature for 24 hours.

Day 2

There will likely be no visible action, which is normal. Discard half of the mixture in the jar (throw it away). Add 150g of your reserved room-temperature water and 100g whole grain rye flour. Stir, put the lid on loosely, and let it sit for another 24 hours.

Stage 2: Cultivate

Day 3

You should start seeing some bubbling action. The capture stage is complete. Keep exactly 75g of the starter and throw the rest in the trash. To that 75g of starter, add 75g reserved water, 35g all-purpose flour, and 35g whole grain rye flour. Stir, cover loosely, and let sit for 24 hours.

Day 4

Repeat the exact same feeding from Day 3: Keep 75g starter (discard the rest), and feed with 75g water, 35g all-purpose flour, and 35g whole grain rye flour. Stir, cover loosely, and let sit for 24 hours.

Day 5

You should now see significant activity and a near doubling in size. Do one final cultivation feeding: Keep 75g starter (discard the rest), and feed with 75g water, 35g all-purpose flour, and 35g whole grain rye flour. Stir, cover loosely, and let sit for 24 hours.

Stage 3: Maintenance

Day 6 & Beyond

By Day 6, the starter should be rising and falling predictably. At its peak (about 6 hours after feeding), it will pass the "float test" (a small spoonful will float in a glass of water), meaning it's strong enough to bake bread!

The Daily Maintenance Feeding: Moving forward, keep 25g of starter (discard or use the rest for baking/discard recipes), and feed it with 50g tap water and 50g all-purpose flour.

If you are a casual baker, do this maintenance feeding once every 24 hours. If you bake constantly or are trying to revive a starter from the fridge, feed it every 12 hours.