Peasant Breads is really a mis-nomer. It really is referring to a rustic, old-world type of bread that usually has some rye in it, since rye is very European, and generally is darker in colour and richer in flavour. It can be made with cracked grains or rolled grains like oatmeal or have added seeds or even fruits added to it. It is definitely not light and fluffy! It usually does not come in the regular loaf shape either. Generally made free-hand, we find peasant breads made into long or even more common rounds shapes, that when sliced make long oval slices.
To darken the colour of any bread, include a little carob powder (of flour) , Postum (a coffee substitute made from grain) or other cereal beverage or even cocoa. You can use dark liquids like coffee.
It is interesting to know that the traditional "black" breads were really brown, taking their colour from the whole grain flours of which they were made--rye or buckwheat, for example. In preindustrial days, oftentimes whole wheat flour was bolted to extract white flour for the upper classes, and then the poor folks' "black"bread was dark because it included extra bran and wheat germ.
Double Rising--Most hearty or peasant style breads will require a double rise. we still let the bread rise once in the bowl and then a second time after it is shaped. Because the tendency of the peasant bread recipes to be a little on the heavy size, the second rise will improve the texture and help lighten them somewhat.
Crustier Crusts Baked in a hotter oven with steam, the same bread develops a thin crispy crust that shines and browns beautifully. Peasant breads usually need to look the part so using steam to bake it's just like how a French bread is usually done to have a crusty outer layer. As for the Peasant bread it will help them to look darker and have a more chewy texture.