HomeGeneralThe Function of Wheat Flour in Pastry and Baking

The Function of Wheat Flour in Pastry and Baking

Flour is the backbone of any bakery or pastry case. From elegant entremets to the humble cookie, pastry does not exist without flour. Those who like numbers need only look to baker’s percentages for evidence. Which ingredient reigns supreme at a permanent level of 100%, unaffected by application or other ingredients? Flour. A thorough working knowledge of flour—its composition, purpose, and classifications—will aid any chef or baker wishing to troubleshoot a recipe or create their own.


Flour is milled from wheat, a widely cultivated type of grass. Wheat kernels are harvested, ground, and sieved to produce the commercial product we use for baked goods, pasta, and sauces. North American bread wheat is classified by protein content, growing season and kernel color.

Soft Wheat

Varieties of wheat with a low protein content are called soft wheats. In addition to being less abundant, these proteins are often also weaker than those found in high-protein wheat.

Hard Wheat

Wheats with a high protein content are called hard wheat.

Spring Wheat

As you might expect, spring wheats are sown in the spring and harvested in the fall. These tend to be lower in protein.

Winter Wheat

Winter wheats are planted in late fall and harvested in the summer. Winter wheats are generally harder, having a higher protein content than spring wheats.

Red and White Wheat

Most wheat varieties are red. That is, their kernels have a reddish-brown outer layer. Red wheats are higher in protein. White wheats have a light tan seed coat and tend to be low protein.

Selective breeding has led to a mix-and-match palette of wheat types, with the most common commercial wheats being:

Hard Red Spring Wheat: 11-16.5% protein
Hard Red Winter Wheat: 10-13.5%
Soft Red Wheat: 9-11%
Hard White Wheat: 10-12%
Soft White Wheat; 10-11%

Millers and manufacturers blend these different types of wheat to produce commercial flours with consistent protein levels. They will sometimes change their proprietary blend in order to match the properties of past batches of flour.


In the US, flour is classified according to the purpose for which it is best suited. Bread flour is commonly used in breads, cake flour in cakes, etc. The difference between flour types boils down almost solely to protein content, except self-rising flour, a soft wheat flour pre-blended with leaveners and salt.

Cake Flour: 7-8% protein
Pastry Flour: 8-9% protein
Self-Rising Flour: 9.5-11% protein
All-Purpose Flour: 9-12% protein
Whole Wheat Flour: 11-15% protein*
00 Flour: 11-12%**
Bread Flour: 12 – 14% protein

*While whole wheat flour is high in protein, the sharp particles from the bran will tear gluten strands, shortening them and producing denser products (the effect mimics a lower-protein flour).

**00 is a finely ground Italian flour. The “00” refers to how finely the flour was milled and offers no reliable indication of protein content.


While protein is the critical variable in different types of flour, other elements warrant consideration, as each has a role to play in flour’s performance.

Protein: 8-13%

Protein provides structure to breads and baked goods through the formation of gluten. The dominant proteins in flour are gliandins and glutenins – the “gluten proteins.”

Starch: 65-77%

As seen most clearly in sauces and custards, starches offer gelling and thickening properties. Starches also stabilize structure and delay staling.

Fiber: 3-12%

Fiber helps retain moisture and add crispness. It can also add color and enhance texture. As customers look to mitigate their indulgences, fiber can also add a healthy boost to bread and baked goods.

Fat: approx. 1%

Fatty materials have been shown to stabilize structure, preventing premature rupture and collapse of air bubbles. Fat can also soften bread structure and prevent staling.

Ash: approx. 1%

This broad term encompasses the minerals and trace elements found in flour, such as iron and calcium. While ash content has historically been considered an indicator of the flour’s quality, this is not necessarily so.



Milling is the process of breaking down the wheat kernel into tiny pieces. These pieces can be sifted to create different types of flour with specific qualities.

Conventional milling vs. stone grinding

Stone milling crushes the wheat kernel into smaller pieces so that some are too small to be sifted out and will remain even in refined flours.


This is the process of removing the bran and germ particles to produce white flours that contain little to no whole grain particles. A flour with a high extraction rate is one in which most of the germ particles have been removed. White whole wheat flour, for example, is a whole grain flour with a high extraction rate. Generally, flours with a higher extraction rate have a higher protein content.


The aging process allows oxygen in the air to react with glutenin proteins, allowing them to produce even longer gluten chains when mixed. Bakers sourcing freshly milled flour may need to experiment with aging the flour to achieve the results they are used to seeing with conventionally mass-produced flour.


Treating flour with chlorine gas and potassium bromate mimics the effects of aging in less time. Most millers have replaced potassium bromate with ascorbic acid due to health concerns surrounding bromate.


Bleaching agents are often used on chemically oxidized flour to mimic the natural lightening that occurs in air-aged flour. Some bakers assert that chemical bleaching weakens flour proteins.


The amount of sugars naturally present in flour is enough to feed yeast for only a short time, so it is common for manufacturers to add malted wheat or barley to flour to encourage the growth of enzymes that will break down flour’s starches into more sugars.


Manufacturers will add specific nutrients to their commercially processed flours to replenish vitamins and minerals lost in the refining process. In many cases, the enrichment of refined wheat flours is required by law.


Other Grains, Alternative and Specialty Flours

Various other grains, seeds, and nuts can be processed and refined to create flours for breads, baked goods, and other pastry applications. Bakers use rye, semolina, and barley to enhance the texture and flavor of breads, cookies, and more. Seeds and grains such as amaranth, quinoa, and millet can offer properties similar to traditional wheat flour while reducing or eliminating gluten. Many bakers are turning to locally milled and grown heirloom wheats with names like Warthog and Turkey Red to add local flair to their baking, explore new flavors, and support area business owners.

Flour Types Outside the US

In the US and UK, flours are named according to the application to which they are best suited. In many European countries, however, flours are named according to a numbering system, indicating the flour’s ash content. For example, the numbering system for flour in Germany indicates the amount of ash obtained from 100g of flour, while the French numbering system indicates the ash content per 10g of flour. American all-purpose flour (protein content between 9-12%) is called Type 55 in France and Type 550 in Germany. The ash content of a flour corresponds roughly to its protein content. French Type 55 flour is higher in protein than Type 45, which is similar to US pastry flour, while Type 80 corresponds to a strong bread flour.



Water affects both gluten development and starch gelation. For example, a high proportion of water to flour will produce cookies with a crumbly texture. Reverse the ratio, and the higher amount of water will result in a cake-like texture, as the water has diluted gluten proteins and allowed for extensive gelation of starches.


As seen in cakes, pie doughs, and other light, tender products, fat inhibits gluten development, resulting in shorter gluten strands. This is where the term “short” dough originates. Pâte sucrée and shortbread cookies each have a high fat content, resulting in shorter gluten strands, yielding a light and crumbly product. In addition, coating flour in fat further inhibits gluten formation by preventing water absorption.


Sugar creates tender baked goods by absorbing water in doughs and batters, leaving less for gluten formation. Starch is another water-loving component of flour and, thus, is also affected by sugar’s hygroscopic qualities.


Acids help the proteins in flour set, and sometimes, if acidic conditions are lacking, proteins will not set. Generally speaking, the amount of naturally occurring acid in common baking ingredients is enough to encourage flour proteins to set. However, it’s worth noting that some ingredient swaps may affect the acid content of a recipe and, thus, the final texture.


Protein content is the most important factor when choosing among standard wheat flours. A flour with a medium protein content, such as all-purpose flour, is suitable for a wide variety of products, from tender cakes to crusty breads. However, a flour with a higher protein content, such as bread flour, can yield artisan-style loaves with superior structure and cookies with an appealing chewy texture. The higher protein content means the flour will form more gluten and a stronger structure. This enhanced structure can trap air or help a product hold its shape. These positive effects of high-protein flour can be seen in applications such as pate a choux and laminated dough, which rely on a stable structure to create a light and airy product. On the opposite end of the protein spectrum, a weaker flour, such as cake or pastry flour, can facilitate soft and tender cakes, biscuits, and scones. Too little structure, though, and the product may not hold its shape. To achieve specific desired results, a baker must sometimes blend flour types to achieve the right balance of structure and tenderness. A thorough understanding of different flours, their protein content, and the roles these play in a recipe will aid a chef in developing recipes that produce consistent, high-quality products.


Flour dust is highly flammable and can explode if ignited, posing a greater risk of combustion than even gunpowder or coal dust. This is primarily due to flour’s starch content. Starch is a carbohydrate, a chain of sugar molecules. Turning your back on a pot of caramel can demonstrate how easily and quickly sugar can burn. The tiny particles in flour burn instantly, creating a severe fire hazard in mills and storage facilities.

(This article appeared in the Winter 2024 issue of Pastry Arts Magazine)

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