You don't use yeast in this bread, the baking soda and the buttermilk help it rise.If you don't have any buttermilk just add one teaspoon of lemon juice or vinegar to a cup of milk. Let it sit for about 15 minutes before you use it. My grandfather was a baker and used to make this bread, it was always so good. I don't make it too make too often because I'd eat too much!!!!
Pre-heat the oven 180 degrees. Grease a baking sheet with melted butter or margarine.
Sift flours and baking soda into a large mixing bowl. Gradually add enough buttermilk to form a soft dough, the amount of milk used depends on the strength of the flour. You might not use all the milk, that's why I wrote 2-3 cups.
Turn on to a floured surface and knead lightly. Make a round shape. Place on the greased baking sheet. With a floured knife make a deep cross on the top of the dough. Brush with water and sprinkle with a little flour. Bake for about 30 minutes or until bread sounds hollow when you tap the underside.