Traditional buttermilk is the liquid whey left behind when milk has been churned and all the fat is extracted as butter. Commercial buttermilk is produced by adding a special bacterial culture to either low-fat or skin milk. Buttermilk contains an acid that reacts with bicarbonate of soda and releases gas to raise the dough in soda bread, scones, biscuits and some pancakes. If no buttermilk is available, use half sour cream or yogurt with half fresh milk. Alternatively, you can mix 1 teaspoon of lemon juice with fresh milk and the dry ingredients.
** Asian Recipes