Flour marked as “Cake Flour” was sold in the United States as early as the 1920’s. This variety is very finely milled from soft wheat, and has an almost silky feel. Plus, it has a low protein content, not to mention that it is also bleached. In fact, the bleaching process alters the structure of cake flour’s starches and fats, resulting in a more acidic pH. It is worth noting that the acidity helps cakes — and other baked goods with a large amount of sugar — rise instead of collapsing. Meanwhile, the low protein content ensures a tender and fluffy texture. Cake flour is great for, well, cakes. But you should avoid it if you’re baking bread.