In a small bowl, combine the yeast, water, and sugar and set aside until bubbles begin to rise to the surface, about 5 minutes.
Warm the buttermilk, oil, and salt in a saucepan to about 115 degrees F. Transfer to a large bowl.
In a separate bowl, sift together the whole wheat flour, baking soda, and 2 cups of the white flour. When the yeast is bubbly and dissolved, add it to the buttermilk mixture. Stir in the flour mixture and beat vigorously 100 strokes.
Add enough additional white flour to make a stiff dough. Turn out onto a lightly floured surface and cover with the bowl for 15 minutes. Uncover and knead well for 5 to 10 minutes, until the dough is smooth and elastic.
Prepare two muffin tins with cooking spray. Pinch off pieces of dough about the size of large walnuts, roll each piece into a ball, and place 2 dough balls in each muffin tin. You will have about 21 "double" rolls.
Cover the rolls with a damp towel and place them in a warm spot until doubled in size, about 45 minutes to an hour.
When the rolls have almost finished rising, preheat the oven to 350 degrees F.
When completely risen, uncover the rolls and bake for 15 to 20 minutes, until golden brown. Remove from the pans immediately and enjoy.