Soda bread pastry flour (made from soft wheat), which has lower levels of gluten than a bread flour. In some recipes, the buttermilk is replaced by live yogurt or even stout. Because the leavening action starts immediately (compared to the time taken for yeast bread to rise), bakers recommend the minimum amount of mixing of the ingredients before baking; the dough should not be kneaded. Various forms of soda bread are popular throughout Ireland. Soda breads are made using wholemeal, white flour, or both. In Ulster, the wholemeal variety is usually known as "wheaten bread" and is normally sweetened, while the term
Sodium bicarbonate and allow passages for steam to escape, so the breading is not blown off during cooking. Baking powder, also sold for cooking, contains around 30% of bicarbonate, and various acidic ingredients which are activated by the addition of water, without the need for additional acids in the cooking medium. Many forms of baking powder contain sodium bicarbonate combined with calcium acid phosphate, sodium aluminium phosphate, or cream of tartar. Baking soda is alkaline; the acid used in baking powder avoids a metallic taste when the chemical change during baking creates sodium carbonate. Sodium bicarbonate can be used to kill cockroaches.