Combine warm water and yeast
Let it stand until it is foamy (about 5 minutes)
Add buttermilk, sugar, oil, eggs, salt and whole wheat flour
Combine thoroughly, then let stand, covered, for ten minutes. (This gives you time to clean up everything but your flour)
Add 3 cups white flour - 1/2 cup at a time, blending well each time
Knead with your machine or by hand for 6-8 minutes, adding enough flour until the dough pulls away from the sides of your mixing bowl
Place in greased container and cover
Let rise for one hour
Punch dough down, then divide in two
Shape into loaves and put into greased bread pans
Optional: prick tops with fork all the way to the bottom of the pan
Let rise for 45-60 minutes; keep covered if your house is cool or drafty
Heat oven to 375, then brush tops of the loaves with about 1 tablespoon buttermilk
Bake at 375 for 28-33 minutes