You don’t need yeast¹ to get lofty bread: Chemical leavening² can add air through an explosive combination of acidic and basic ingredients. While Native Americans used refined potash to leaven³ griddled breads – an early example of chemical leavening – this version became popular during the lean years of the Irish Potato Famine.

With potato crops failing, impoverished⁴ Irish people started mixing loaves using soft wheat flour, sour milk and baking soda.

Now, dense⁵ loaves of soda bread are a nostalgic treat that’s a perfect pairing with salted Irish butter.