1) In a small saucepan, gently heat the water and buttermilk to 110 degrees F (43 degrees C). Place the yeast and 1/4 teaspoon of the sugar in a small bowl; pour half of the heated buttermilk mixture into the bowl and let proof for 5 minutes.
5) During the last 15 minutes of rising, preheat your oven to 375 degrees F (190 degrees C). Bake risen bread until nicely browned and loaf sounds hollow when rapped on the bottom, about 35-45 minutes. Remove from pan and allow to cool completely on a wire rack before slicing (I never can wait that long).
Adapted from She Runs She Eats