1. Assess Your Oven Temperature Accuracy: Before you even start baking, place an oven thermometer inside your oven. Preheat your oven to your desired baking temperature (e.g., 450 F or 230 C) for at least 30-60 minutes. Compare the thermometer reading to your oven’s display. If there’s a significant difference (more than 25 F or 15 C), you’ll need to adjust your oven’s setting accordingly for future bakes. A hotter-than-accurate oven can quickly scorch the bottom.

2. Evaluate Your Baking Surface: If you’re baking directly on a preheated baking steel or pizza stone, consider its placement. If the bottom is consistently burning, the heat source from the bottom element might be too intense. Try moving your baking surface to a higher rack in the oven.

3. Introduce a Heat Shield: For the first part of your bake (often when covered, if using a Dutch oven), place a layer of aluminum foil or an empty baking sheet on the rack below your baking surface. This acts as a barrier, deflecting some of the direct heat from the bottom element away from your loaf.

4. Use Parchment Paper Effectively: Always bake your sourdough on parchment paper. This not only makes transferring the dough easier but also provides a slight insulating layer between the dough and your hot baking surface. Ensure the parchment paper extends slightly beyond the base of the loaf.

5. Monitor During the Bake: Once your loaf is in the oven, keep an eye on it. Around halfway through the baking time, or when you remove the lid if using a Dutch oven, carefully check the color of the bottom crust. If it’s already looking significantly darker than the top or sides, it’s time to intervene.

6. Insulate the Bottom During Baking: If you notice the bottom browning too quickly, carefully slide a second piece of parchment paper or a small piece of aluminum foil under the loaf for the remainder of the bake. Alternatively, you can place the entire loaf (still on its original parchment) onto a baking sheet for the latter half of the baking time. This provides an additional buffer from the direct heat.

7. Adjust Oven Rack Position Mid-Bake (if safe): If the top is browning perfectly but the bottom is still too dark, and you haven’t used a heat shield, you can carefully move the entire baking vessel or loaf to a higher rack for the final 10-15 minutes of baking. Be cautious when doing this to avoid burns.

8. Cool Properly: Once baked, immediately transfer your sourdough loaf to a wire cooling rack. This allows air to circulate around the entire loaf, preventing moisture from condensing on the bottom and softening the crust, and also stops residual heat from the baking surface from continuing to cook (and potentially burn) the bottom.