1. Assess Your Sourdough Starter’s Activity: Before you even mix your dough, ensure your starter is robust and active. It should double or triple in size within 4-8 hours after feeding, have many bubbles, and pass the float test (a small spoonful floats in water). A weak starter is a primary cause of dense bread because it lacks the power to create enough gas for a good rise.

2. Properly Mix and Develop Gluten: After combining your ingredients, focus on thorough mixing and gluten development. Techniques like stretch and folds or coil folds, performed over several hours during bulk fermentation, build strength in the dough. You want the dough to feel elastic and strong, able to hold its shape. A lack of gluten development means the dough can’t trap the gas produced by the yeast, leading to a tight crumb.

3. Control Bulk Fermentation (First Rise): This is arguably the most crucial stage. Under-fermented dough won’t have enough gas production, resulting in a dense, tight crumb. Over-fermented dough, on the other hand, will have exhausted its food supply, leading to a weak structure that collapses in the oven, also resulting in a dense crumb. Look for visual cues: the dough should increase in volume by 30-50% (depending on hydration and flour type), show bubbles on the surface, and feel jiggly.

4. Gentle Shaping and Handling: When shaping your dough, be firm but gentle. The goal is to create tension on the surface while preserving the gas bubbles developed during bulk fermentation. Over-handling or degassing the dough too much will expel precious gas, leading to a denser loaf.

5. Monitor Final Proofing (Second Rise): Similar to bulk fermentation, both under-proofing and over-proofing can cause a dense crumb. For under-proofed dough, there isn’t enough gas for expansion. For over-proofed dough, the gluten structure has weakened and can’t hold the gas, leading to collapse. The “poke test” is a good indicator: gently poke the dough with a floured finger; if it springs back slowly, it’s ready. If it springs back immediately, it’s under-proofed. If it doesn’t spring back at all, it’s over-proofed.

6. Ensure Adequate Oven Spring: Baking in a preheated Dutch oven or with steam creates a humid environment that allows the dough to expand rapidly before the crust sets. This “oven spring” is vital for an open crumb. If your oven isn’t hot enough or lacks steam, the crust can set too quickly, restricting expansion and leading to a denser interior.