16 hours ago, Smithy said:
(The gold flecks in the interior holes are surface crumbs that were picked up from the bread board.) This crust is hard. It looks from the cross-sectional ring as though there's a tough, dry ring around the perimeter. Does this mean I cooked it for too long at high heat before turning the oven down? If not, what? What should I try next?
I've noticed that you changed your description from tough to hard, if so, that means much over baking.
Try to do the following:
Spray your loaves with water before putting them in the oven and introducing the steam. Bake all the way at 440dF, but remove the loaves while somewhat lighter then your target shade. Make sure that the interior is fully baked before you do - use a thermometer if you have one.
Let the loaves chill somewhat, at least until just warm to the touch,but they can even be frozen at that stage.
Now place them in 400-410 dF until fully browned and hopefully crisp to your liking.
I should mention that I haven't tried it on sourdough.
I really hope it will work for you.