Dissolve yeast in water, add sugar. Stir until dissolved and let set until yeast begins to froth.
Mix flours, salt, baking soda, oil and buttermilk and beat at low speed, then medium for 2 mins.
Add herbs and mix.
Knead 5 mins.
Place dough in lightly oiled bowl, cover and let rise in warm place until doubled (approx. 1 hr.)
Punch down dough and divide in half. Cut each into 3 pieces. Roll each into 14" ropes.
Braid 3 ropes into 1 loaf, making 2 loaves.
Allow to raise, covered, on the baking sheet until it has doubled in size (roughly 45 mins.)
Preheat oven to 350º and bake 25 to 35 mins, until golden and hollow sounding when tapped. Remove from baking sheet and cool on a wire rack.