Bleached Flour Vs. Unbleached Flour: What's The Difference?

Most standard baking recipes call for all-purpose flour, so why are there several different varieties to choose from in the baking aisle? Fortunately, as long as a recipe doesn't specify a particular all-purpose flour to use, you can narrow down your choices to either bleached or unbleached flour. You might think the main difference between the two would be obvious — one is bleached, one is not — but it turns out that both flours are actually bleached. 

Once wheat is milled and processed, it appears naturally beige or yellow in color. So the flour is then either whitened with the use of chemical bleaching agents (bleached flour) or it's left out to naturally whiten over time from oxygen exposure (unbleached flour). Other key differences between bleached and unbleached flour have to do with color, texture, price, and sometimes flavor. Plus, choosing one flour over the other can be advantageous in regard to the final outcome of certain baked goods.

So why does flour even need to be bleached? The answer is, it doesn't. But, over time, consumers and bakers have preferred lighter-colored flours since either bleaching process results in flour with a finer-crumb that's easier to use in baked goods, than if it wasn't bleached after being milled. At one point, all flours were lightened naturally, but maintaining the flour as it whitened took time, space, and money. Chemical bleaching expedited this process, making bleached flour less expensive than unbleached flour.

When it comes to texture and color, bleached flour reigns supreme with its lighter texture and color compared to unbleached flour. This can be favorable for baked goods that are meant to have a vibrant hue, like a pink velvet or red velvet cake, cookies, and pastries. Unbleached flour — because it isn't chemically treated — features glutinous proteins that aren't as strong as those of bleached flour, leading to a denser, less-tender structure in baked goods. Unbleached flour is often better suited for rustic breads where chewiness is desired. Additionally, in recipes that call for fermentation, like tangy sourdough bread, naturally aged unbleached flour is able to develop a more robust flavor over time.

Considering each flour and the baking applications they're best suited for, along with their price points, is it necessary to stock both in your pantry? While each flour can lead to a variety of desired outcomes (as long as you measure your flour correctly), using unbleached flour in baked goods where bleached flour is more appropriate — and vice versa — won't dramatically affect the final result. Stocking one or both flours in your pantry is a matter of personal preference, depending on how precise you'd like your baking to turn out.