It appears everyone has their favorite Irish soda bread recipe. Some with caraway seeds, some with raisins, some with both, some with neither.
The essential ingredients in a traditional Irish soda bread are flour, baking soda, salt, and buttermilk. The acid in buttermilk reacts with the base of the baking soda to provide the bread’s leavening. This leavening from buttermilk and baking soda is what gives the bread its name, “soda bread”.