What’s the Difference Between Bleached and Unbleached Flour?

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.

What is bleached 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. 

What is unbleached flour?

Unbleached flour is flour that is whitened naturally as part of the ageing process.

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.

What are the differences between bleached and unbleached flour?

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.

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.

How are bleached and unbleached flour used in cooking?

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.

Bleach and unbleached flour recipes

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.