1. 1. Ensure Your Loaf is Fully Cooled: This is the most critical first step. Cutting into a warm loaf can compress the crumb, making it appear denser than it actually is. Wait at least 2-4 hours, or even overnight, for the loaf to cool completely to room temperature.

2. 2. Prepare Your Cutting Station: Place your cooled sourdough loaf on a clean cutting board. Have a sharp serrated bread knife ready.

3. 3. Make a Clean Slice: Carefully slice the loaf roughly in the middle, or about one-third of the way in from one end. Aim for a clean, even cut that reveals the full cross-section of the bread.

4. 4. Observe the Overall Structure: Take a moment to look at the entire cut surface. Notice the distribution of holes, the texture of the bread itself, and any variations from the center to the crust.

5. 5. Identify the Crumb Type (Open vs. Tight): Open Crumb: Characterized by irregular, varied-sized holes distributed throughout the loaf. Some holes might be quite large, while others are smaller. The bread itself should feel light and airy. This often indicates good fermentation, proper shaping, and sufficient hydration. Tight Crumb: Characterized by small, uniform holes, or a dense, cake-like texture with very few holes. The bread might feel heavy or gummy. This can suggest under-fermentation, over-proofing, insufficient hydration, or issues with shaping.

6. 6. Look for Consistency: Is the crumb consistent throughout the loaf, or are there dense spots, large tunnels, or a very dense bottom? Inconsistencies can point to uneven mixing, shaping issues, or temperature variations during fermentation.

7. 7. Note Any Gummy Texture: If the crumb feels wet, sticky, or gummy, even after cooling, it could indicate underbaking, too much hydration for the flour, or insufficient fermentation.