Making Cooking Easy: The Best Of Chef Raphael Irish soda bread is made with just four ingredients; flour, salt, baking soda, and buttermilk (sour milk). Soda bread gets its rise, not from yeast, but from the baking soda (bicarbonate of soda) reacting with the acid (soured milk or buttermilk). Buttermilk has a nice thick creamy texture with a rich tangy buttery taste that makes this bread tender. Whereas in the past it was the liquid leftover, after churning butter it is now commercially made by adding a bacteria to whole, skim, or low-fat milk. You can make your own buttermilk by adding 1 tablespoon of white distilled vinegar, cider vinegar, or lemon juice to 1 cup of milk. Let stand 5 to 10 minutes before using.