Mix the yeast and water, let stand for 5 minutes. Mix again.
Add oatmeal, buttermilk, sugar, butter, salt and whole wheat flour and all purpose flour. Work in enough to form a soft dough. Knead until the dough is smooth and elastic.
Place in a large bowl and cover with damp cloth. Let rise in a warm place (not oven) for 2 hours.
Punch down the dough and let rest for 10 minutes. Form 2 loaves and place in buttered loaf pans. (9x5x3inch)
Re-dampen the cloth and cover the loaves, allow to rise another 45 minutes in a warm place until proofed.
Preheat oven to 375 degrees. Bake for about 40 to 45 minutes.