Soft bottom crust of bread using baking stone?
I have been pleased with the results of my sourdough breads lately... nice crumb and flavor, getting into a good rhythm with my baking schedule. Last two bakes have resulted in my loaves with softer crust that the rest of my bread... it's left me stumped.
I really want to use a baking steel at some point. But I'm scratching my head as to why the bottom of bread is suddenly less dark and crispy as the rest of the bread.
Depending on my bake, I generally bake at 475-500F with steam for 20-25 mins, and then finish off dry at 425-450F. I preheat my stone for at least 30mins, usually closer to an hour. For steam, I use rolled up towels on the bottom rack placed inside a cast iron grill pan. I bake two loaves at a time. I haven't changed this set up in over a year, and previously had largely uniform crust. If anything the crust was darker.
The only thing that has changed is the flour ... I had previously used CM from Costco, and recently switched to Bob's Artisan Bread Flour. I also use parchment paper (I flip my dough out of the bannentons onto the paper, score, and slide into the steamy oven). I also use a different brand of parchment paper (aren't they all the same?).
Is the flour to blame here? Any insight?