In a large bowl, dissolve yeast in water. Beat in the buttermilk, milk, oil, sugar, salt, baking soda and 2 cups of flour until smooth. Stir in enough remaining flour to form a soft dough.

Turn onto a floured surface; knead until smooth and elastic, about 6-8 minutes. Place in a greased bowl, turning once to grease top. Cover and let rise in a warm place until doubled, about 1-1/2 hours.

Punch dough down. Divide into 18 pieces; roll into balls. Place on greased baking sheets, or line with parchment paper. Cover and let rise until doubled, about 30 minutes.

Spray or brush with butter. Bake at 400° for 13-18 minutes or until golden brown. Spray or brush with butter.