Butter two 8 1/2-by-4 1/2-inch loaf pans. Dust with all-purpose flour, tapping out excess.
In a small saucepan, combine molasses, 1 cup water, and cider. Heat over medium, just until mixture reaches warm room temperature. Sprinkle yeast over top and let stand until yeast is bubbly, about 5 minutes.
Combine flours and salt in the bowl of an electric mixer fitted with a paddle attachment. Beat to combine. Add the yeast mixture and beat on medium until well combined, 2 to 3 minutes. Cover with plastic and place in a warm spot until doubled in size, about 1 1/2 hours.
Divide dough between prepared pans. Drape with plastic wrap and let stand until doubled in size, about 1 hour more. Meanwhile, preheat oven to 350 degrees with a baking sheet on lower rack.
Transfer loaves to oven, being careful not to deflate. Bake 30 minutes. Remove bread from pans and place on preheated baking sheet. Continue baking until hollow-sounding when tapped on bottom and an instant-read thermometer reads 190 to 200 degrees, about 30 minutes more. Transfer to wire racks to cool completely. Loaves will keep in an airtight container at room temperature for up to 3 days.