Wash the potatoes and cook until soft. Cool a little, peel and press through a potato press. Set the potato mixture aside to cool.
Weigh the water for the pre-dough, add the sourdough and stir. Add the yeast. Weigh out the flour for the pre-dough and mix to a pulpy mass. Let it stand for two hours at room temperature so that it starts up.
When there are bubbles on the dough add the remaining flour, the bread spices and the salt. Add the pressed potatoes. Be cautious about adding the rest of the water because the potatoes are quite moist - it's better to add a little more water later. Mix in the bowl with the mixing spoon. Continue kneading with your hands for a few minutes and then, covered, let stand for two hours at room temperature. The result is a moist, sticky, soft dough, which is now stretched three times with the dough card in the two hours and then folded again. The dough is then placed in the refrigerator for 24 hours.
Take the dough out of the refrigerator the next day and shape it into bread on the well-floured work surface and place in a proving basket for another 1.5 hours to relax. Meanwhile preheat the oven to 250 ° C. I bake with the pizza stone, so I preheat for at least 45 minutes. Then turn the bread out of the proofing basket onto the stone or baking sheet, cut into it and put it in the oven. Bake for 15 minutes with plenty of steam.
After 15 minutes, reduce the oven to 210 ° C top / bottom heat. Open the oven door completely for a short time to let the steam off and bake the bread for another 40 minutes. The crust will open up in a rustic way and should take on some color. After the baking time, take it on the oven, sprinkle it with water and let it cool down. The knock test shows whether the bread is done.
I have been planning this bread for a long time. I bought the potatoes 5 weeks ago. The result is a rather soft dough that shouldn't be tried as a beginner. That is why I have given the degree of difficulty as medium.