Elena Molokhovets, the Mrs Beeton of Czarist Russia, wrote of making bread on a country estate: of keeping sourdough cultures alive from one baking to the next by the simple procedure of not washing out the wooden troughs in which the dough was mixed; of drying flours in front of the fire before they could be used to make bread; of putting white loaves to prove in a tub of cold water - when the loaves rise to the surface, they are ready for the oven; and of making wheat loaves with skimmed milk or yoghurt, but rye bread with water.
‘Black’ bread - which was the food of peasants rather than princes - may have been more brown than black, but might contain wheat as well as rye. Its sourness is sweetened by molasses, which also help colour it. This recipe uses toasted breadcrumbs, again it helps the colour, but it also makes a lighter loaf. In Germany it is common practice among professional bakers to recycle stale rye bread in this way.