Learn the science behind:
If you’ve ever moved between countries or went to a specialized (online) baking store, you might have experienced it: flour analysis paralysis. There are so many different types of wheat flour, making it hard to decide which one you need. Do you need 00, cake, 45, bread, all-purpose, 110, self-raising, or maybe whole wheat flour?
To help you choose, you need to know what to look for. Understanding the protein content, hardness, and extraction rate of your flour will help you make sense of the wide variety out there.
- The properties to look out for in wheat flour
- Reviewing the different flour names and codes
- Recapping: which flour do you need?
The properties to look out for in wheat flour
At their core, the different types of flour only differ in two key aspects:
- The type of wheat it’s made from
- The way that wheat has been processed
Once you know which variety you need and how it has to be processed, you’ll be able to find your ideal flour, despite the confusing names and terminology. Let’s have a look at both factors in some more detail.
Wheat variety dictates application
Any wheat flour is made by milling wheat kernels into fine particles. But, not all wheat kernels are the same. There are a lot of different wheat varieties. When distinguishing between different wheat varieties, bakers and cooks will be most interested in two specific properties:
- Protein content
- Hardness of the kernel
If you want to bake a good fluffy bread or pasta, you need wheat flour with a high protein content. The proteins, gluten, ensure that you can stretch and pull the dough. If you’re baking a cake, or making a delicate tart shell on the other hand, you do not want any gluten formation, so you’re looking for a low-protein flour.
The protein content of a flour is solely determined by the wheat it’s made from and how that was grown. Once harvested, the protein content no longer changes.
The protein content of wheat can vary widely, from as low as 6% to as high as 20%. Most commercial wheat flours contain somewhere between 7 and 15% protein. Since the protein content is so important for the functionality of the wheat flour, you’ll often find it mentioned on packaging.
Flour processors will always test the protein content of their wheat, alongside other quality control checks such as moisture and ash content.
During milling, a lot of pressure is exerted on wheat grains to make sure they break into smaller pieces. Some wheat are very hard, and take a lot of effort to break. Others are softer, making it easier to break, and thus mill, them.
If it’s harder to break a wheat kernel, chances are that the starch granules within that wheat kernel get damaged in the process. Damaged starch absorbs water more easily than undamaged starch does. In breads this can be desirable, in cakes, not so much. It’s why softer flours tend to be used for cakes, whereas harder flours are more suitable for breads.
Generally speaking, a harder wheat type contains more protein than a softer variety. However, this rule of thumb doesn’t always go up. There exist high protein soft wheat flours and low protein hard wheat flours.
Processing impacts flour behavior
But wheat variety alone doesn’t yet explain the difference between all flour varieties out there. Milling of the wheat itself is a multi step process involving several roller mills, sieves, etc. before wheat is turned into flour. Manufacturers can pull several levers that impact the properties of the flour, such as:
- Extraction rate: whole wheat vs. white flour
Remember that a wheat kernel is made of several different layers, which are split into different fractions during the milling process:
- bran: This is the outside of the kernel. It contains most fibers and minerals.
- endosperm: This makes up the largest part of the wheat kernel. It has the highest starch percentage.
- germ: This is where a new plant will start growing if you’d planted the seed. It contains the highest percentage of protein and fat.
All flours contain the endosperm, but the bran and germ can be sieved out (partially).
To indicate just how much is sieved out, manufacturers use the extraction rate. Whole wheat flour has an extraction rate of 95-100%. That is, the bran, germ and endosperm are all present in the same ratio as they would have been in the original wheat. White flour on the other hand generally has an extraction rate <75%. It does not contain the germ nor the bran.
Instead of extraction rate, some manufacturers may refer to ash content. The ash content of a flour is a measure for the fraction of minerals present in the flour. The bran contains by far the most minerals. As such, whole wheat flours, or flours with a high extraction rate, will have a higher ash content. Keep in mind that ash content also depends on the wheat variety, whereas extraction rate does not.
The presence of absence of the bran and germ have a big impact on the appearance and behavior of a flour. The bran contains a lot of fibers. Those fibers can cut into a gluten network, making it more challenging to make a light and fluffy bread from whole wheat flour, than white flour. Those fibers also need more moisture to hydrate fully, so products made from whole wheat flour tend to need more water than those made from white flour. The germ contains quite a lot of fat which can turn rancid and oxidize. As a result, it can reduce the shelf life of flour quite significantly. The germ and bran aren’t as white in color as the endosperm, explaining the brown, speckled color of whole wheat flours.
You can make bread, cookies, and pastry with flours of any extraction rate. They will turn out differently though. For making pasta you do need flours with a lower extraction rate.
In certain parts of the world, such as the USA, wheat flours may be bleached. Bleaching makes a flour whiter in color. It is done to extend the shelf life of the flour by delaying oxidation and the formation of off-flavours.
Bleaching also impacts the behavior of flour. Bleached flour has shown to be well suited for making very soft, light cakes.
Another variable is particle size. Some flour types (e.g. semolina) are deliberately milled to a larger particle size than others. In some cases you can easily see the difference in size, other times it is hard to even find it given on the label.
Manufacturers may decide to mill flours more finely depending on the final application. For instance, flours made for cakes tend to be milled more finely than those for baking bread.
Reviewing the different flour names and codes
There is no globally used, uniform way of naming wheat flours, unfortunately. Over time different systems have developed which are used in different areas of the world. Europeans especially have developed a range of different systems.
That said, knowing the importance of wheat types and processing can help you decipher the meaning of all these names more easily. We’ll have a look at some of the most commonly used grading systems.
Italian flours – from 00 to 2
Italians start by grouping flour into two main wheat varieties:
- Soft wheat
- Durum wheat, that is, the harder wheat varieties
Within soft wheat the extraction rate is used to distinguish between different processes. 00 flour is the ‘whitest’ flour with the lowest extraction rate and ash content. From there the extraction rate increases for 0, 1 and type 2 flours. After type 2 comes whole wheat flour, making a total of 5 classes.
Hard wheats are grouped differently using terms such as semolato and semolina. There do not exist proper english translations for these classifications. In English most are translated as semolina. They differ in their extraction rate as well as particle size.
For making pasta it is crucial that you use a hard wheat variety. Durum wheat is a hard wheat variety. In some cases, hard wheat flours are also classified with the 00 – 2 system. If so, you’d be looking for a 00 durum wheat flour to make pasta.
French flours – from 45 to 110
The French flour naming system fully relies on using the extraction rate to distinguish different types of flour. The lower the number, the lower the extraction rate, thus the ‘whiter’ the flour.
French flours start at 45, which is most refined, going up to 150 which is whole wheat flour. In between you’ll have flours numbered 55, 65, 80 and 110. The numbers refer to the dry ash content of the flour type, which is again related to the extraction rate. A flour with number 45 contains a maximum ash content of 0.45%.
Note that the French don’t necessarily have a way to distinguish between the different types of wheat in this classification system. You’ll need to look for other cues to find that distinction.
The Spanish, German en Polish flour naming systems are very similar to the French system. The German system runs from 405 to 1600, so they’ve rouhly muliplied the French numbers by a factor 10.
British & American flours
British and Americans do not use codes. Instead, they use a more descriptive naming system that tells you what that flour is best suited for. It’s probably the easiest to use system from a consumer’s perspective.
All purpose & self raising flour
All-purpose is a flour meant to be suitable for, exactly, all purposes. Hence it’s not great at one thing, but decently good at a lot of things. It has a moderate protein content and extraction rate appropriate for a white flour.
The British will also have self raising flour. This is all purpose flour mixed with a pre-determined quantity of baking powder.
Bread flour has a high protein content. It tends to have a very similar extraction rate compared to all purpose flour (so milled in a similar way) but it’s made from different wheat varieties.
Cake flour has a lower extraction rate and protein content than all purpose flour. Whereas all purpose flour is quite similar to French 55 flour, cake flour is more comparable to the 45 type.
Online you will find a lot of ways to make your own cake flour. Generally, it involves mixing cake flour with corn starch. Whereas this does lower the overall protein content, it does not give you the same extraction rate. Therefore, you will continue to notice differences.
Recapping: which flour do you need?
For those of you living in the US or UK, choosing the right type of flour is quite straightforward. The name on the pack says it all. However, if you’re buying flour elsewhere, or making something that doesn’t match a regular flour’s name, use the following two steps to decide which one you need:
Step 1: decide on protein content.
Cakes, cookies & scones do well with a low(er) protein content. Pasta and bread work better with a higher protein content.
Step 2: delicate vs robust?
A whole wheat flour will always result in a less delicate product. Products made with it will be denser and will require more water. However, it does contain more fiber, which can be an important health-based choice.
ps. Looking for flour for an application that we didn’t mention above, and not sure where to start? Leave a comment and we’ll help you figure it out!
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The Conversation.com, Science in the kitchen: the fresher the flour, the softer the cake, 2017, link ; Did you know that fresher flour can lead to a better cake?!
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