Mix water, molasses, and yeast; let sit for 5-10 minutes until foamy.
In a bowl, combine rye flour, bread flour, salt, and caraway seeds.
Add yeast mixture to the flour mixture; stir until a shaggy dough forms.
Knead by hand or in a mixer for 8-10 minutes until smooth.
Place dough in an oiled bowl; cover and let rise 1 ½ hours.
Punch down, divide dough, shape into two rounds.
Cover loaves and let rise 1 hour.
Preheat oven to 450°F (230°C); bake loaves 35-40 minutes until brown.
