Bleached flour has a slightly lower protein content than unbleached flour because of the chlorination process it goes through. Protein develops into gluten, which provides structure in baked goods. Less protein in bleached flour means less gluten and a softer, lighter texture and finer grain, just the qualities you want in more delicate pastries like cakes, pastry dough, muffins and shortcakes.

According to Shirley Corriher, author of Bakewise (Scribner, 2008), there’s "a major difference due to protein content—products are significantly tougher and drier with unbleached flour." Another reason to use bleached flour is when you want a truly white color, like in a white cake.

Unbleached flour is better for sturdier baked goods, like yeast breads or pizza dough. Its higher protein content allows the yeast to rise and still support the structure of the dough.

If you prefer using only unbleached flour but want a lower-protein flour occasionally, you can create your own by substituting potato starch for 10 percent of the flour.