There is a lot of writings about rye bread. In my opinion real one comes from Finland where I often live and learned to bake it. Finns are particularly crazy about 100% rye bread: it contains coarse rye flour, salt and water, starter and sometimes some store bought yeast. In my experience the flour is most crucial: it should be coarse and whole grain. Scientific approach as often described by obsessive technicians (as opposed to bakers) is really unnecessary. The proper recipe comes with experience. Thus, the measures below are approximate. I developed a very good recipe in Finland, but when I came back to USA I had to redo it to adapt to local ingredients. In any case, the version described below passed the most stringent test: by my Finnish wife, who now must have this bread every day. In fact, we do not buy bread at all nor bring it from Finland anymore (we used to bring a year's supply and freeze it). In following recipe I use exclusively coarse, whole grain rye flour: Hodgson Mill is excellent.
1. Make starter:
a. half cup of coarse rye flour and similar weight of water (I use room temperature boiled water to get rid of excess chlorine). Mix, put in a glass container and tightly cover (1 quart jar with screw top is fine). Keep in room temperature or better in a warm place.
b. feed it: add similar amount of flour and water, once a day or every two days. You will see that it sort of foams eventually and bubbles: it is OK. If it stays flat: start again.
c. After a week or so it is ready. If you do not use it, store in refrigerator, and feed it as above once every week. After feeding you may keep it for a while in warm place until it revives-foams again. If the jar gets too full, discard some. If you use some, re-start building it up, as above.
2. Make sponge.
Mix together about 1 cup, more of less of starter (remember to replenish your starter jar gradually), flour and water. I use about 2 cups flour and same amount by weight of water. It will be a dense, shaggy, sticky mass. Put in bowl and tightly cover. Next morning it will become much looser, bubbly and acidic smelling. Keep it for 1-3 days in warm place (not hot), depending how intensely sour bread you like.
3. Make dough.
a. dump the sponge from the bowl (do not scrape it clean, so the residue will jump start next batch) into mixing bowl. Add another half to one cup of starter. Add flour - another cup will result in one large loaf (the total used will be 3 cups). Add water-no more than same amount as flour by weight, but add gradually, so the dough will be sticky and soft and manageable. Add some salt and about 2 teaspoons of dry yeast. I also add about one third (more or less) of gluten to get better body. Mix for about 10 min. on low in a mixer (or by hand). You may also try to omit yeast-the bread may be quite good but denser. Cover and wait about 10-20 min.
4. Final proofing.
dump the dough on well-floured counter and using a scraper fold it a couple of times on itself. Finally form a log not bigger than your baking pan. Put it in the pan (best sprayed with PAM and lined with baking parchment paper). You can also bake it free-form, round, but it will not raise up, but spread horizontally forming a rather low loaf. Cover with plastic sheet and keep 1-2 hours in a warm place (I use oven with oven light on).
Preheat oven to 450 F and on lower shelf put a pan with hot water. Bake about 10-15 min, then lower temperature to 375 F and best cover the bread loosely with aluminum foil. Bake another 45-60 min. Take bread out of the pan (that's how parchment helps) and check if knocking on bottom produces a hollow sound. If it does not, return loaf (without pan) to oven for another 5-10 min. Cool completely on a rack (best overnight). You can eat it then or keep for a day or two in a plastic bag and start eating then.
6. Eating and storage.
The bread will mature over several days and the taste will change and improve. Slice it thinly (about 1/4 inch) with a heavy, sharp knife, very carefully since it will be hard and the knife can slip and cut you (it happened to me). Note: this bread is not intended to have a crunchy, thick crust like a French baguette. Store in a closed plastic bag. Mine kept very well up to 2 weeks (by then we ate it all and a new batch was baked).Remember that this bread has a lot of fiber and it may influence your digestive system to the better.