I am trying to make a sourdough bread with least effort. My receipe is as follows: Add sourdough starter, rye flour, salt and water, mix. Put in a iron tin and wait for 24 Hours for the sourdough to do its work. Bake it.
To avoid that the bread sticks to the iron tin, I lay out the tin with baking paper. I have 2 tins, one with coating and one without. In the tin without coating, the bread gets ugly black spots, and I wonder how to avoid this. I found out that the spots are tasting of metal, so I am pretty sure now that the metal makes the spots, and not burning baking paper.
I especially wonder if the baking paper and tin combination is playing a role here. I know that the sour PH of the dough can corrode baking tins, but I thought that this would not matter when using baking paper.