What is the difference in bleached and unbleached flour

Are they really that different?

If you’ve ever found yourself staring blankly at the rows of seemingly identical (but somehow impossibly different) bags of flour in the baking aisle, you’ve probably wondered: “What the heck is the difference between bleached and unbleached flour?” You’ve come to the right place.

How Is Flour Made?

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Credit: danchooalex/Getty Images

danchooalex/Getty Images

Flour can be made from a variety of plants (see: "A Practical Guide to Alternative Flours"), but you’re likely most familiar with wheat flour. Flour is made by milling wheat grains into a fine powder.

People have been producing flour for more than 6,000 years. Early civilizations likely used stone, or a mortar and pestle, to grind the grains. We now have technologically advanced flour mills, but the process remains essentially the same.

Bleached vs. Unbleached Flour

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Credit: Elizabeth Laseter

Elizabeth Laseter

You might be surprised to learn that flour is a pale yellow color when it’s first milled. It’s actually the aging process—and exposure to atmospheric elements—that turns the flour white, usually after a few months. Aging doesn’t just affect the flour’s color—aged flour bakes better, too.

On Food and Cooking author Harold McGee notes that “aging affects the bonding characteristics of the gluten proteins in such a way that they form stronger, more elastic doughs.”

So … wait a minute: If flour turns white naturally over time, what’s the point of bleaching it?

Bleached flour is simply flour that was aged chemically (usually with peroxide) to speed up the process, rather than naturally over time. Benzoyl peroxide (yes, that benzoyl peroxide—the one from your acne cream) is one of the most commonly used bleaching agents during flour processing.

Unbleached flour, meanwhile, has been naturally aged after being milled. That’s not to say it hasn’t been treated with chemicals—potassium bromate is often added—but it usually has been treated with fewer chemicals.

Is Bleached Flour Bad for You?

Maybe, maybe not. The European Union, Canada, and China have banned peroxides in flour processing because of health concerns, but American manufacturers can still use them. It’s up for debate how ingesting small quantities of peroxides can affect your health in the long run, but the bleaching process does cause the flour to lose a lot of nutrients—namely protein and calcium. Do with that information what you will.

When Should You Use Bleached Flour?

All Time Favorite Chocolate Chip Cookies

Credit: Aaron Kirk; Prop Styling: Heather Chadduck; Food Styling: Pam Lolley

Bleached flour is slightly softer than its unbleached counterpart. Foods made with bleached flour tend to be softer and have more volume than those that aren’t. It can improve the texture of soft baked goods like cookies, cakes, quick breads, muffins, etc.

Try these recipes:

• All-Time Favorite Chocolate Chip Cookies
• Oatmeal-Chocolate Chip Cookies
• Chocolate Fudge Sheet Cake With Chocolate-Cream Cheese Frosting
• Customizable Quick Bread
• Carrot-Apple Muffins With Orange Glaze

When Should You Use Unbleached Flour?

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Credit: Photo by Rebecca Firkser

Unbleached flour is denser than bleached flour, so it works well for sturdy desserts like pastries. Note: Unbleached flour takes longer to produce, so it is typically more expensive than bleached flour.

Try these recipes:

• Brie-and-Fig Puffed Pastry Bites
• Cinnamon-Orange Rolls
• Cinnamon Bun Eclairs
• Sea Salt Soft Pretzels
• Basic Rugelach

Does It Really Make a Difference?

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Credit: sandoclr/Getty Images

sandoclr/Getty Images

Yes, choosing one flour over the other can have a very subtle effect on how your recipe tastes. Should you lose sleep over it? Probably not. The differences will be so slight, only someone with a very refined palate will be able to detect it. In the end, it’s all about personal preference.

Flour is one of the most important ingredients in any baking project, and a pantry staple in most people’s kitchens. When you’re buying flour from the store, you may have noticed that, among the many other different types of flour, some will be marked as ‘bleached’ and others as ‘unbleached’. If you’re wondering which type you need, take a look at our guide to the key differences between bleached and unbleached flour.

The main thing that separates bleached flour and unbleached white flour is how they get their white colour. White flour is typically made from milled wheat - although many other types of flour are also available - with most of the bran and germ from the grain removed. This means that white flour is paler than wholegrain flour, but when it is first milled, it is actually a yellowish colour, rather than pure white.

Flour gets its colour from naturally-occurring substances called carotenoid xanthophylls, and if left to age, these substances will oxidise, changing the colour of the flour from yellow to white. Ageing flour naturally can take between 1 to 2 months, however, and many producers in the USA add bleaching agents like benzoyl peroxide to speed up the process. This flour is known as bleached flour, while flour that is whitened naturally, through ageing, is known as unbleached flour. 

The bleaching process can strip some of the nutrients out of the flour, but both bleached and unbleached flour is often fortified with extra vitamins and minerals, so these can simply be added back in after bleaching. Bleached flour and unbleached white flour are typically almost identical in terms of nutrients, with both containing the same amounts of protein, fat, carbohydrates, and fibre, as well as the same number of calories per cup. 

For a more nutritious flour, wholegrain beats both bleached and unbleached white flour, as it still contains the healthy bran and germ that are removed from white flour. Wholegrain flour is higher in fibre, vitamin E, manganese, copper, and antioxidants, all of which provide important health benefits.

Whether you use bleached or unbleached flour in your baking is really a matter of choice. There are several differences between the two, but unbleached flour will work perfectly well in a recipe that calls for bleached flour, and vice versa. 

Bleached flour tends to be a brighter white than unbleached flour, and results in brighter looking bakes, so some people prefer it for cosmetic reasons. It also has a softer texture and finer grain, which means it absorbs liquids more easily, lending itself to light or flaky bakes like pie crusts, quick breads, cookies, pancakes and waffles. Bleached flour is also a cheaper option, as it takes less time to produce.

The slightly coarser texture of unbleached flour works well for denser, heartier foods such as cakes, muffins, biscuits, biscotti, and pizza crusts. It also holds its shape better, which is useful for baking puff pastries, eclairs, yeast breads, and popovers.

Many people opt for unbleached flour to avoid using bleaching agents in their food. Some people are able to detect a bitter, chemical taste in bleached flour, while others are concerned about the potentially harmful effects of consuming benzoyl peroxide. In fact, bleached flour is outlawed in several countries, including EU countries, Canada and China, due to health concerns.

It is important to bear in mind that unbleached flour may still contain chemicals that are added for other reasons, such as potassium bromate, which is used to help dough to rise. Unbleached does not mean chemical-free, so if you want to avoid additives in your food, you need to check the label.

We’ve chosen two of our favourite flour-based recipes, one using bleached flour, and the other using unbleached flour. If you do prefer one type of flour over the other, however, feel free to switch, as both recipes will work well with either.

This homemade pizza dough from Sally’s Baking Addiction uses unbleached flour for a denser, chewier crust. The recipe is super simple, with clear step-by-step instructions, and produces a deliciously soft pizza base that will make you wonder why you ever got your pizza anywhere else.

This ultimate pie crust recipe from One Sarcastic Baker recommends using a lower gluten flour such as pastry flour or bleached flour for a lighter texture. There are also other helpful hints for achieving the ultimate flaky pastry, such as using iced water in your dough to control the number of gluten strands created.

If you want to find out more about flour, including how it’s made, and the different varieties of flour available, take a look at these interesting facts about flour.

Is it OK to use unbleached flour instead of bleached?

Is there a difference between bleached and unbleached flour when baking?

Which flour is best for baking?

Does unbleached flour cook differently?