1. 1. Prepare Your Dough and Container: After mixing your sourdough ingredients, transfer your dough to a clear, straight-sided container. This is essential for accurate measurement. Lightly oil the container if you wish, to prevent sticking, though many prefer not to.

2. 2. Mark the Starting Volume: Immediately after placing the dough in the container, use a permanent marker or a small piece of tape to mark the exact level of the dough on the side of the container. This will be your baseline for tracking its expansion.

3. 3. Monitor the Dough Temperature: If you have a kitchen thermometer, insert it into the dough to get an internal temperature reading. Ideal dough temperature for bulk fermentation is typically between 75-80 F (24-27 C). A warmer dough will ferment faster, and a cooler dough will ferment slower. Adjust your fermentation environment if needed.

4. 4. Observe for Visual Expansion: Place your marked container in a warm, consistent spot. Over the next few hours, periodically check the dough. You are looking for a significant increase in volume. For most sourdough recipes, bulk fermentation is considered complete when the dough has increased by about 30-50% from its original volume. Some recipes might call for up to a 75% increase, so always refer to your specific recipe’s guidance.

5. 5. Look for Surface Bubbles and Domed Top: As the dough ferments, you should see small bubbles forming on the surface. The top of the dough should become slightly domed and feel airy. These are indicators that the yeast and bacteria in your starter are actively producing gas.

6. 6. Perform the Jiggle Test: Gently jiggle the container. Properly bulk-fermented dough will jiggle like a firm jelly. If it feels very slack and spreads out, it might be over-proofed. If it feels dense and doesn’t jiggle much, it likely needs more time.

7. 7. Consider the “Windowpane Test” (Optional): While more commonly used during mixing, a quick windowpane test can also give you insight. Gently pull a small piece of dough and stretch it thin enough to see light through it without tearing. If it stretches easily and forms a thin membrane, your gluten development is good, and the dough is likely well-fermented.

8. 8. The Sourdough Proofing Time Chart (General Guidance): Dough Temperature 70 F (21 C): Expect 6-10 hours for 30-50% rise. Dough Temperature 75 F (24 C): Expect 4-7 hours for 30-50% rise. Dough Temperature 80 F (27 C): Expect 3-5 hours for 30-50% rise. Note: These are approximate times. Always prioritize the visual and tactile cues over strict timing, as starter activity and flour type also play a role.