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  • Writer's pictureJulia

The Science of Baking - Flour Power!

Updated: Jun 5, 2020

It's that time of year again when the Great British Bake Off is back on our TV screens and the nation dons it's collective pinny and heads to the kitchen, eager to have a go at making some of the masterpieces they see on the screen. It's also the time when I get asked more questions than at any other time of the year. It usually starts off something like this: "Who do you think will win bake off? You should go on it. How do you ... (insert question) ..." Or "Did you see bake off the other day? Actually, you will probably know this, why don't my ...(insert name of baked goods)... turn out like that?"

As you have probably realised by now, I love to bake! Big cakes, small cakes, biscuits, bread, puddings and anything in between, it doesn't really matter, there's nothing I like more than messing around in the kitchen creating edible treats. And I have had my own share of failures too, or caketastrophies, as I like to call them. This is usually because something has gone a bit awry during the baking process, because baking is a science and if you change one little thing, the unexpected can happen. Sometimes this is a happy surprise but it can also be an unmitigated disaster!

I have learnt a lot over the years, trying different recipes, testing and tweaking and with the new series of GBBO on TV I thought it would be fun, if not educational, to look at the science of baking. Heck, it might even be useful to some of you! In this post I am starting with one of the staples of any baker and that is flour.

There is evidence that man has used wheat as food for thousands of years. In Egypt, tombs along the Nile contain ancient murals which show wheat planting and harvesting, the grinding of flour and making of bread, and in 1948 archaeologists discovered an ancient village in Iraq where they found two different types of wheat similar to those grown today. Wheat is still eaten in primitive forms in many parts of the world and similar crude tools to those used thousands of years ago can still be seen in use today.

Wheat found in the excavation of ancient cities often appears carbonised as though the husk had been removed by heat. Heating the grain makes the glumes easier to rub off. Other cereals, rice, corn and maybe some varieties of early wheat could be popped, like what we know today as popcorn. The moisture inside the hard outer coat would turn to steam in the heating process to explode the grain glumes.

Wheat flours, the most commonly used flours, are milled from the wheat berry. The berry consists of three parts - the outer hull, or bran; the small germ, or embryo, inside; and the endosperm, a starchy material that feeds the embryo.

Today, so many foods contain wheat that it is often an unnoticed part of our diet but bread, of course, is the most familiar wheat product. There are many different types of flour available and when a recipe requires flour we should ask ourselves "does the choice of flour make much difference to baking?" The answer, of course, is yes. The right flour, combined with practical skill, will give you the best results. Flours vary in composition and, broadly speaking, are defined according to the type of wheat from which they are milled.

Wholemeal or wholewheat flour contains the whole of the wheatgrain (including bran and germ) with nothing added or taken away.

Wheatmeal or brown flour usually contains about 85-90% of the wheatgrain.

White flour usually contains about 72-74% of the wheatgrain.

White flour, including strong bread flour and plain or all purpose flour, consists of the milled endosperm, with the bran and germ removed. Plain flour is milled to be used in a variety of ways and is made with a combination of hard and soft wheats. Strong flour is milled specifically for bread and is made only from hard wheat.

Wholemeal and brown flours give variety and colour to baking but goods baked with them have a limited rise and a closer texture than those made with white flour. It can also have a slightly bitter flavour and for these reasons many wholemeal breads are made with a combination of wholemeal and white flour.

A protein present in the flour, glutenin, when combined with water forms gluten, which is stretchy and elastic. When goods containing gluten are cooked, the water inside is converted into steam which expands, blowing up the gluten like a balloon, forming air pockets. As the goods continue to cook, the gluten sets, trapping the air, and it is the gluten framework which forms the structure of the product.

The quality and quantity of gluten produced by a flour are both important. Tough gluten is hard to blow up while soft, sticky gluten blows up easily but collapses quickly. For the best quality bread, a good elastic gluten is needed which will blow up into large balloons but will hold its shape until set by the heat of the oven.

The quantity of gluten is also important because gluten absorbs water, which is the reason why we use strong flour in bread making because it is made from wheat that has a higher protein content and will therefore have high rising and high water absorbing properties. Goods must be well kneaded or beaten to develop the gluten structure and ensure retention of the gases produced when combined with yeast. Strong flour is available in both white and wholemeal.

Soft flour is made from weaker grades of wheat as they contain less protein and therefore produce a less glutinous dough than strong flour.

Self-raising flour is generally produced from normal or general-purpose (plain) flour and is more commonly sold as white flour, although wholemeal varieties are also available. Aerating agents are added to self-raising flour to make baked goods rise. It is mainly prepared for shops and supermarkets as it is most suitable for household cooking. No fermentation occurs in the products made so no ripening of gluten is needed. For this reason a weaker grade of wheat is used. Carbon dioxide is released during the baking process and this guarantees a sufficient rise in the finished product.

High ratio cake flour is mainly manufactured for flour confectionery and is especially suitable for large quantity cake making which carries a high percentage of sugar content, and the traditional sponge and cake mixes made by 'all-in' methods. This flour is milled from soft wheats.

Semolina flour is a high gluten white flour made from durum or hard winter wheat. It is most often used in pasta and may be labelled as pasta flour. It makes good bread when used with other flour but by itself it makes a heavy loaf.

Rye is a hardy grain that grows well in cold, wet climates where wheat does not. That's why so many Scandinavian and Russian breads are rye breads. Rye flour contains some gluten but must be mixed with wheat flour. Medium or light rye flour consists only of the endosperm. Dark rye and pumpernickel are milled from the bran, germ and endosperm of the rye berry and are coarser, darker flours.

Graham Flour was named after Dr. Sylvester Graham, a 19th century health food devotee. It's a coarsely ground wholewheat flour milled from soft winter wheat. It has less gluten than wholewheat flour and will not rise as high. You don't see this one in the UK very often but a number of American recipes use it.

Buckwheat flour is made from the triangular seeds of a cereal grass. It adds a pungent, earthy flavour to bread. It is a high fat flour low in gluten.

Corn flour is milled from the whole kernel of corn and adds a sweet flavour to bread. It is gluten free.

Oat flour, made from oats that have been ground into powder, is very low in gluten and must be mixed with wheat flour, but is high in protein.

Soya flour gives bread a moist texture and is very high in protein but should be used sparingly because it adds a slightly bitter flavour. It is gluten free.

Quinoa flour, an ancient pearly grain from Peru, gives bread a nutty flavour. It's very high in protein but is gluten free.

Millet flour, milled since Neolithic times, and a staple food in parts of Africa and Asia, adds a yellowish colour and a gritty texture to bread.

Amaranth flour was a staple of the Aztecs. It has a nutty, slightly spicy flavour. It is higher in protein than most flours but is low in gluten.

Barley flour, milled from a flour that dates back to the Stone Age, has a slightly sweet taste, a soft texture and a low gluten content.

Other ancient varieties of wheat include Einkorn and Kamut Khorasan. Spelt flour is also made from an older version of wheat.

Rice flour, the flour most commonly used in gluten free breads, is milled from either white or brown rice. It makes bread with a sweet flavour and chewy texture. Brown rice flour includes the bran.

Other non-wheat flours: You can also get other flours which are not made from wheat, such as hazelnut and peanut and also coconut, potato, pea and chickpea. Though each of these flours will differ in their nutritional make up to wheat flour and to each other, they are not inherently better for you unless you have an allergy to wheat/gluten.


If you have managed to make it this far then you deserve a little reward. I love to make my own bread, although these days I tend to let my bread maker do all the hard work. I have recently added a new 'Recipes' page to the website where you will find some of my favourite recipes - not just for cakes but savouries and dinners too - and I am kicking it off with one of my favourite bread recipes - Mango and Macadamia Nut Bread. I am making this available for you all to try so click on the link below and head on over to the recipes page to grab your copy. This recipe is particularly well suited to bread makers but it should work just as well in a conventional oven. Let me know how it turns out if you give it a go.

Mango & Macadamia Nut Bread

Of course, flour is also used in most cakes too so contact me here for a free, no obligation quote if you are in need of a celebration cake. Alternatively, email or private message the Facebook page.

Sharing the cake (and bread ) love!


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