Czech style rye bread

Sour dough starter:
To get a sour dough starter started, start with a small amount (~1/4 c) whole wheat or whole rye flour and mix 1:1 with water.  Let sit 24 hours.  Feed again, adding enough water and flour to double the volume.  Do this for at least a week, leaving the mixture on the counter at room temperature covered with a clean cloth to prevent things from falling into it.  To maintain the starter, either feed once per day keeping the mixture at room temperature or feed once per week if the starter is in the fridge.  If your starter is more watery, the starter will be more sour.  If it is a bit drier, it can be a bit easier to maintain.  You can tell if the starter is active because it will be bubbly.  You can feed the starter with any flour to maintain it.  Generally a starter made from rye flour will work slightly better with rye bread and a starter made with wheat flour will work slightly better with wheat bread.

A sour dough starter is a culture of wild type yeast and lactobacilli.  The lactobacilli produce acid that breaks down the glutens in rye flour, letting it rise.  If you try to use commercial yeast for rye bread, it will not rise.

Rye bread:
This is not an exact recipe.  The most important thing in bread is the proportions rather than exact amounts.  More oil will make a more elastic dough.  A wetter dough will produce a more moist, less dense dough.  I have not yet matched the exact texture of Czech rye with any flour I've gotten in the US so don't expect to be able to match the texture exactly.  Sometimes you can get white rye flour - this produces a much lighter bread than standard Czech rye.  It essentially has the hull of the grain removed before grinding.  The most common rye flour in US grocery stores is whole rye flour - this has much more of the hull than usually available in the standard Czech flour and is more coarsely ground.  It will therefore produce a rougher bread than the rye bread available in Czech grocery stores.  The dough will rise better if you let the starter sit at room temperature for 24 hours before starting bread.

Mix:
1-2 teaspoons salt
3 tbsp olive oil (butter or another oil can be used)
2-4 tablespoons caraway seeds, whole
about 2 cups sourdough starter

Add flour to make a wet dough.  Between the starter and the flour added to make the dough, about 1/2 of the flour should be white flour from wheat and about 1/2 should be rye.  The more rye the tougher the bread.  You need at least 1/3 white flour to get it to rise.  It does not need to be kneaded rigorously.  Let it rise between 4-12 hours - it depends on how active the starter is.  If you pulled the starter out of the fridge, your yeast is not very active at the beginning.  Then put a lot of flour on a pan to prevent sticking and form into a mound that is fairly smooth on top.  Cover with a clean cloth and let rise about 4-6 hours.  Cook at about 375F for about 30 minutes, preferably on a baking stone and with a pan of water in the oven to make the crust tougher.