What's the Difference Between Bleached and Unbleached Flour?

What's the Difference Between Bleached and Unbleached Flour?

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Kelli Foster
Sep 21, 2015
(Image credit: Kelli Foster)

Flour is an important pantry staple. It plays a crucial role in so many baking projects from cookies and cakes, to quick breads and pies. When shopping for a sack of all-purpose flour, you're faced with a choice: bleached or unbleached flour?

Which one do you reach for? And do you know what sets them apart?

The Difference Bleached and Unbleached Flour

Technically, all flours are bleached, but it's the process by which it happens that sets these two types of flour apart. Bleached flour is treated with chemical agents to speed up aging, while unbleached flour is bleached naturally as it ages. This affects not only the color and grain of each type of flour but the end result of baked goods.

All-purpose bleached flour.
(Image credit: Kelli Foster)

More About Bleached Flour

Bleached flour uses bleaching agents (commonly benzoyl peroxide and chlorine gas, among others) to speed up the flour's aging process. This results in a whiter, finer-grain flour with a softer texture. Some people with sensitive palate can notice a difference in taste with bleached flour.

The bleaching process softens the flour, the effects of which are reflected in finished baked goods. Foods made with bleached flour tend to have a softer texture, more volume, and a brighter color than those made with unbleached flour.

Bleached flour is best for making cookies, pie crusts, quick breads, muffins, and pancakes.

All-purpose unbleached flour.
(Image credit: Kelli Foster)

More About Unbleached Flour

Unbleached flour is flour that has aged naturally after being milled. It has an off-white color, which continues to dull as it ages, and a more dense grain than bleached flour. Just because this type of flour hasn't been bleached doesn't necessarily mean it hasn't been treated with other chemicals. All brands are different, so it's important to read the label to know what you're buying.

Unbleached flour also takes longer than bleached flour to produce, and because of this, it's usually more expensive.

Having a denser texture, unbleached flour provides more structure in baked goods, which makes it an ideal base for things like yeast breads, cream puffs, eclairs, and pastries.

Bleached and unbleached flour. Can you see the difference?
(Image credit: Kelli Foster)

Can They Be Used Interchangeably?

As it ages, flour is naturally bleached from exposure to oxygen. Unbleached flour, which takes longer to produce, ages naturally, while bleached flour uses chemical agents to speed up the process. The end result is two types of flour: one with a bright white hue and fine grain (bleached flour) and one that's pale and off-white with a denser grain (unbleached flour). Because of their different textures, each flour produces slight variations in baked goods.

So what does that mean for your baking? While there may be differences in color, volume, and even smell of your baked goods from using one flour over the other, they will be slight. For baked goods, the overall basic outcome is the same with either flour. Your muffins will still rise, your cookies will still be delicious, and that layer cake will turn out just fine.

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