Self-raising flour is plain flour with baking powder already added, giving home bakers a convenient shortcut for cakes, scones, and batters. The raising agent is distributed evenly through the flour at the mill, so every scoop carries the same leavening power, removing the measuring step where many baking failures begin. It suits recipes developed for it; substituting it for plain flour, or vice versa, unbalances the recipe unless the raising agent is adjusted. The baking powder loses strength with age, so old self-raising flour bakes flat, and it should be stored cool and used within months. It is a British baking staple, less common in countries where cooks add leavening themselves as a matter of habit.