Different kinds of flours are made from different kinds of wheat. Bread flour is milled from a hard wheat, resulting in a flour that has more gluten, the elastic substance that develops when flour gets wet and is manipulated by kneading, beating or stirring. Gluten helps to give bread its structure. Cake flour is milled from soft wheat. Its gluten content is less than hard wheat,  so it is used for cakes and pastries that need tenderness. All-purpose flour is good general use flour and is made from a blend of hard and soft wheat.