Temperatures recorded in the oven during a dutch oven sourdough bake. 20 minutes at 500F with the dutch oven lid on, 20m at 400F with it open.

Green = oven temperature throughout. Blue = baseline kitchen temperature (thermocouple cold junction temp).

• Before 1st blue line: preheating. Yellow line = inside a cold cast iron dutch oven. Oven was already warm from baking something else.
• 1st blue line to 2nd: baking with lid on. Yellow = probe in the loaf here onward. I was surprised the internal temperature has pretty much maxed out by the end of the first 20 minutes.
• 2nd blue line + 20 minutes: baking with the lid off.
• After 20:27 / green line dropoff: oven open, loaf cooling. I know you’re supposed to cool to “room temperature”, but even at 150F the crumb was pretty stable when I cut the loaf, with no obvious tearing or sticking to the knife.

Compare to the previous bake where I forgot to reduce the oven temperature after the first 20 minutes. The crust was black/inedible, but the interior was still totally fine.