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.
Here are the black spots
Here is how i prepared the pan
The other bread turned out ok (same oven, same time)
Best Answer
I do something similar but use reusable non stick sheet. Mine is rated to 250°C and I use it up to 240°.
My loaf tin is plated steel, and looks very similar to yours. I suspect your baking paper isn't fully waterproof over the rising time, and is allowing the acidic water from the dough to react with the metal.
You might find that simply double lining the tin is enough. You could experiment with foil under the baking paper, or even wiping cooking oil over the inside of the tin before putting the paper in.