Grind the wheat and rye (do not sieve; include the germ and bran). Add the water, mix by hand and allow to rest. for 30 minutes.
Add remaining ingredients (yes the oat groats are dry) and mix by hand until all the flour is mixed in. Allow to rest 20 or more minutes.
Turn out onto floured work surface and pat out. Fold right third over middle third. Brush off excess flour. Fold left third one other two. Rotate 90 degrees and pat out. Repeat folding and turning 2 more times. Place dough back into container and allow to rest for 20 or more minutes.
Repeat step 3 folding only twice. Allow to rest for 20 or more minutes.
Repeat step 3 again, folding twice. Allow dough to rest 8 hours or overnight in a very cool place. Can be refrigerated or even outside if properly covered.
Divide dough into 3 equal pieces by weight.
Pre-shape the dough and allow to rest for 30 minutes. Do final shape. I like to use a loaf pan so that needs to be sprayed with a non-stick spray. Allow to rise until doubled in bulk, about an hour and a half. Maybe more depending on environment. Preheat oven to 350 F.
Score loaves. Brush with cornstarch slurry, egg white or your desired glaze. Sprinkle with seeds if desired. I like to use the multi-seed blend. Bake until internal temperature reaches 200 F.