Sift the flour into a bowl. Add the salt and sugar. Dissolve the yeast in the water and pour in while stirring. Just stir until no more flour is visible.
Cover the bowl and let the dough rise at room temperature for 3-4 hours.
Line a proofing basket or bowl with a cloth. Sprinkle the cloth with rye flour. Use a spatula to move the dough, which is very bubbly, into the basket. Sprinkle with flour again and cover loosely. Let rise for 2 hours at room temperature.
Preheat the oven to 230 degrees top-bottom heat.
Place the baking sheet upside down on the basket or bowl, turn it over and lift off the basket or bowl with the cloth. Put the tray in the oven. Bake for an hour. After half an hour, switch the temperature down to 180 degrees.
You can save yourself the second letting go. It does not harm the quality of the bread. Then it`s just more of a flatbread.