As a generic term, flour can mean a fine, dry powder ground from some form of vegetable matter, but unless a recipe says otherwise, what is meant is wheat flour — specifically, white wheat flour.
Some flours are used to provide body — such as wheat or rye flour — because they contain a lot of fibre; others such as water chestnut flour, which contain far less fibre, are used more as a starch for thickening.
Flours are graded differently in different countries; there are surprisingly no international consumer-facing standards and it’s rare that countries share the same flour grades. This is probably owing to both varieties of wheat available, and consumer preferences.
Most of wheat flour — 70 to 80 % — consists of carbohydrates.
Wheat contains protein. When mixed with water, these proteins form what is known as “gluten” — an elastic framework within the dough. If you chew on wheat kernels, the gum-like mush that you can feel between your teeth is gluten. Gluten traps gases released by yeast in bread dough by forming cell walls around the gas. This gives bread its light texture, and makes it rise. The more protein a flour has, the stronger the gluten framework to trap the gases during rising. You will want a good strong gluten framework for bread so that it will hold the gases released by the yeast for rising.
Flour also contains “proteases” which like to digest gluten, making the bread dough sticky, inelastic, and flat. Almost all bread recipes call for a small amount of salt to be added, as salt keeps these proteases from being active and feasting on your gluten.
Baking with flour is all about how much gluten you want. You want a lot for yeast-risen breads, or you get horrible loaves. But you don’t want a lot in cakes or pastries, or you get tough crusts and coarse unappealing cakes. Thus, the wide range of flours now available for cooking.
How much gluten a dough can potentially develop is dependent for the most part upon how much protein there is in the flour. It’s expressed as a percentage — 8% protein, 14% protein, etc. To work this out yourself, look at the nutrition label on the bag of flour you have bought. If it says 9 grams of protein per 100 g, your job is done: the protein content is 9%. If it says there are 5 grams of protein per 50 g, your work is still easy: you only have to multiply by 2 to get 10% protein. It’s a little trickier if the package says something like 3 g of protein per 30 g, but with a spreadsheet or calculator you can easily arrive at the number of 10% protein (since you have to multiply 30 x 3.3333 etc. to get 100, you multiply 3 by 3.333 etc. as well, to arrive at 10 — well, near enough, anyway.)
The following table compares the differences in flour grinds and blends in different countries.
|All-purpose||100% hard wheat. Can be used for anything.||75% hard and 25% soft. Not recommended for bread.||Plain flour. Not recommended for bread.|
|Cake flour||Generally sold as “cake & pastry”||Called cake flour||Use either self-rising flour, or plain flour.|
|Pastry flour||Generally sold as “cake & pastry”||Called pastry flour||Use plain flour.|
|Bread flour||Exceptionally high gluten Flour made for commercial|
|High gluten content for home bread-making; equivalent of Canadian all-purpose||High gluten content for home bread-making; equivalent of Canadian all-purpose. Also called “strong flour”|
|Plain flour||Is used as Canadians use “all-purpose” flour, except can’t be used for bread.||Equivalent of American all-purpose flour, including unsuitability for bread.||Used like all-purpose flour, but can’t be used for bread.|
|Self-rising flour||You can sometimes find it on shelves in small bags||Primarily used in Southern States||Used throughout UK|
|Strong flour||British term for bread flour. Use all-purpose in Canada.||British term for bread flour. Use bread Flour.||Used throughout UK for bread.|
|Whole wheat flour||Same as American and British.||Same as Canadian and British.||Same as American and Canadian, except called wholemeal.|
|Wholemeal flour||In Canada called “whole wheat” flour.||In America called “whole wheat” flour.||British term for “whole wheat” flour.|
Flour in the UK tends to be moister than North American flour; when making North American recipes using UK flours reserve a bit of any liquid called for to see if it really needs it.
Enriched White Flour
Under the laws of the UK, Canada and the United States (the US passed its flour-enrichment law in the 1940s, the UK in 1956), white flour must have added to it:
- Niacin / Niacinamide (Vitamin B3);
- Thiamine (a B1 Vitamin);
- Riboflavin (vitamin B2);
- Folic Acid: (a B vitamin);
White Flour vs Whole Wheat
White flours use only one part of the wheat grain — the endosperm. Whole wheat flour (aka wholemeal flour) includes the bran; whole grain flour uses all the wheat grain — the endosperm, the bran, and the germ. In most of the world, the terms “whole wheat” and “whole grain” are synonymous, though not in Canada.
The preference is nothing new; white flour has been considered desirable for thousands of years. It looks purer than whole wheat flour, and because the extra refining pushed up its cost, it was also a status symbol. White flour also made for better bread. The germ and bran (found in whole grain flours) impede the development of a good, elastic gluten. A good, elastic gluten allows a nicely-risen loaf, and good texture and crumb to the bread.
White flour is also often bleached. Bleaching removes from the flour a yellowish pigment, the same as is also found in potatoes and onions. It does, however, destroy vitamin E. Flour is allowed to age for a month or two before being shipped as aging improves its baking qualities, though today this aging process is accelerated greatly with a gas, chlorine dioxide, that is often also used for the bleaching.
Nutritionally, the thinking is that whole grain better is just plain better for us. Though the score card is somewhat balanced by enriched white flour having many important vitamins and minerals restored to it, white flour is still missing the fibre of whole grain as well as some other nutrients. But whole wheat’s high-fibre can also reduce the nutritional value of the bread because it reduces the time that material spends in the body, allowing less time to extract nutrients, whereas white flour makes the nutrients now restored to it by law easily accessible to the body’s metabolism.
Wheat bran has a substance that can inhibit the body’s intake of calcium. Half the children in Dublin developed rickets during the Second World War (“The Emergency”, as they called it) when their minimal calcium rations intake combined with whole-wheat bread to cause the rickets in the children.
White flour is easier to store and lasts longer in storage. The oils in the bran and the germ can go rancid, shortening the storage life of the whole wheat flour. This can be a critical consideration if you are attempting to lay in a supply of flour for any length of time.
So, it isn’t quite as simple as some make it out that white flour is evil, whole-wheat flour is good. Both are great, and there’s a time and a place for each. And, it’s great that we’re living in the first time in history that ordinary people have had any choice at all.
Canadian flour is the first and still the greatest Canadian success story. Canadian wheat makes the finest flour in the world, bar none. Despite everything that is said about bread flour vs cake flour vs pastry flour, somehow magically Canadian all-purpose flour basically handles all those tasks effortlessly. Canadian home cooks and home bakers, in general, don’t really experiment with different types of flour — if you say flour in Canada, it means all-purpose, end of story.
Here apparently is the breakdown of Canadian all-purpose white flour:
- 73.0% carbohydrates;
- 13.0% protein;
- 14.0% moisture (including 1.0% fats.)
The cake and pastry flour reasoning would say that the protein content is too high, so there must be some other factor involves which makes it truly “all-purpose.”
The better flours on British grocery shelves proudly advertise that they are made from Canadian wheat.
“Buy French” movements in France have been trying to persuade French bread makers to switch from Canadian to French flour, but the bakers haven’t budged.
Mix flour first with cold water (equal amounts of each) before adding to a hot liquid.
Flour used to be shipped in cloth sacks, which let through moisture that could cause flour to lump. Nowadays, supermarket flour needs no sifting: it’s evenly ground, pre-sifted at the mill, and shipped in paper bags which keep the flour dry. Most people now just skip the step of sifting flour when a recipe asks them to do it. Sometimes, though, a recipe writer will insist that it’s vital to introduce air into the recipe.
Flour as a thickener
When you thicken a sauce with flour, it seems you can stir the sauce forever with nothing happening, but then the instant you leave the stove for one second, disaster strikes the pot and you have lumps for days. Here’s what’s happening.
Flour is starch, and a lot of it, and these starch granules are held together by molecular bonds. At around 60 C / 150 F, these molecular bonds break, and admit water into the granules. The granules swell up as the water surges into them, and “gelatinize” (become goopy). When your sauce hits this magic temperature range, this all happens at once, but not before.
In a liquid, wheat flour reaches its maximum thickening power at 100 C (212 F.)
To avoid this, stir continuously, or, use a thickener such as Instant Flour or Instant Clearjel which behave better with hot liquids.
Other non-wheat flours, bearing in mind that you will have to work without gluten.
White flours are enriched even if the packages don’t list the added vitamins and calcium as additives.
- 1 cup of all-purpose flour or plain flour, unsifted = 5 oz (140 g)
- ¼ cup of all-purpose flour or plain flour, unsifted = 4 tablespoons = 1 ¼ oz (35 g)
- 1 ½ cups of flour, unsifted = 8 oz (225 g)
- 2 ¼ cups of flour, unsifted = 12 oz (350g)
- 1 cup of cake flour, sifted = 4 oz (115 g)
- 1 pound of all-purpose or plain flour = 450 g = 3 ½ cups unsifted = 4 cups sifted
- 1 pound (450 g) of cake flour = 4 ½ cups
- 1 pound (450 g) of whole wheat flour = 3 ½ cups
- 1 oz (30 g) flour = 3 tablespoons
- 25 g flour = 3 scant tablespoons
- 100 g all-purpose flour or plain flour, unsifted = 3 ½ oz = ⅔ cup flour
- 500 g all-purpose flour or plain flour, unsifted = 17 ½ oz = 3 ⅓ cup flour
- 275 g Flour = 10 oz = 2 cups
Store flour in an airtight container. Whole wheat flours should be refrigerated or frozen.
Even the ancient Greeks preferred white flour — if they were upper class and could afford it.
In Rome, dark flours were for bread for the poor. Their white flour would still have been darker than our white today, as it wasn’t until the 19th century that technological progress made it possible to remove all the bran.
Now, however, class preferences have reversed — there is an increasing tendency for the upper classes to prefer darker flours, and white bread is becoming the bread of the poor.
Canadian National Millers Association. Flour types. Retrieved from http://www.canadianmillers.ca/flour_types.htm in June 2004.