A bowl with dough, showing the gluten network

Gluten – Its Role, Importance, and Impact on Pizza Crust

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Gluten is a crucial component that provides structure to our baked goods. But what exactly is gluten, and why is it so important in baking? This post explores its role and significance

What Is Gluten, How Is It Formed, and Why Is It Crucial in Baking?

Gluten is a rubber-like, elastic, and sticky substance that forms when two proteins (glutenin and gliadin) in wheat flour react with each other in the presence of water. The only sources of gluten are grains such as wheat, barley, rye, and spelt.

In yeast-leavened baked goods, gluten plays a crucial role in providing the dough with elasticity and strength. The gluten network traps the gases (CO2) produced during fermentation, allowing the dough to rise in volume both before and during baking.

Of all the grains that contain gluten-forming proteins, wheat is “unique”. What sets it apart is its high content of glutenin and gliadin, as well as the specific ratio between them. This combination enables the production of gluten in sufficient quantity and quality, making wheat ideal for baking large-volume goods. Other grains lack this essential quantity and quality of gluten-forming proteins, and therefore cannot produce gluten to the same extent as wheat.

During the mixing/kneading process, glutenin and gliadin interact with water and each other through physical agitation, resulting in the formation of gluten; Gluten cannot form without this specific chemical reaction between glutenin and gliadin in the presence of water.
Glutenins contribute to the dough’s elasticity and strength, while gliadins add extensibility and the ability to stretch. The ratio between these two proteins in the flour determines the dough’s specific properties of extensibility and elasticity, as measured by the P/L ratio of the Alveograph.

Please note that flour itself does not contain “gluten,” but rather gluten-forming proteins! “Gluten” is not a substance found in flour, but instead, it is formed when the gluten-forming proteins, glutenin and gliadin, interact with each other in the presence of water. When we refer to the “gluten content in flour”, we are actually referring to the amount of gluten-forming proteins present in the flour.

Similarly, individuals who are sensitive to gluten (such as those with celiac disease) are not actually sensitive to gluten itself, but rather to the gluten-forming proteins that compose it (glutenin and gliadin).

The Role of Gluten in Baking

Gluten plays a crucial role in the preparation of leavened baked goods. Here is how it accomplishes this:

  • During kneading, tiny air cells form in the dough.
  • During fermentation, yeast produce carbon dioxide as a byproduct, which then gets “pushed” into these air cells.
  • Thanks to the elasticity of gluten, the cell walls are able to expand without tearing. Without gluten, the cell walls would tear, allowing the gas to escape, resulting in a dense and flat end product.

Gluten, therefore, provides the dough with an elastic structure, allowing gas cells to expand without tearing or “puncturing”, enabling the dough to rise and increase in volume. Without gluten, achieving the desired volume in our baked goods would be impossible (apologies to our celiac friends).

In general, the more gluten bonds there are in the dough, and the stronger they are, the more volume the dough will gain during fermentation and baking. In other words: more gluten = a baked good with a larger volume.

Gluten also plays a crucial role during the baking process by coagulating and hardening, which gives the baked good its firm and “springy” structure. The coagulation of gluten, along with the gelatinization of starch, is responsible for this structure. Without a sufficient amount of gluten in the dough, we will end up with a flat, dense baked good that lacks “body”.

How Can We Determine the Gluten Content and ‘Strength’ of a Specific Flour?

The most straightforward and intuitive method for determining the gluten content or strength of flour is by examining its protein content. White flour (and only white flour – see note below) consists mainly of gluten-forming proteins (approximately 80% of the proteins in white flour are gluten-forming proteins). Therefore, the higher the protein content in (white) flour, the greater the amount of gluten-forming proteins it contains.

In other words – the higher the protein content in the flour, the more gluten it (potentially) contains.

With that being said, there are two exceptions to determining the gluten content in flour based on its protein content:

  1. Wholemeal flour. Wholemeal flours are ground from the entire wheat kernel, including the bran and the germ. Although the bran and the germ contain proteins, they do not contain gluten-forming proteins (glutenin and gliadin). Therefore, there is no correlation between the protein content and the gluten content in wholemeal flour.
    This is also true for semi-wholemeal flour – the less “pure” the flour is (the higher its ash content), the higher its protein content will typically be (but as mentioned, this does not necessarily mean that it contains more gluten).
  2. Italian flour. In the case of Italian wheat, from which Italian flours are milled, there is no direct correlation between the protein content and the gluten content (or “strength”) of the flour. This is why Italians use the W index to measure the strength of their flours, a measurement that is irrelevant for non-Italian flours. For more information, please refer to this post: Is Italian Flour Essential for Making Pizza? Everything You Need to Know about Italian Flour.

Still in the context of gluten strength, it is important to consider both the quality AND quantity of the protein. Different types of wheat have varying properties and protein compositions. Two flours may have the same protein content but differ in protein quality, which will ultimately impact the behavior of the dough and the final product. For more information on this subject, please refer to the following post: The Ultimate Guide to Pizza Flour – How to Choose the Ideal Flour for Pizza (section ‘Protein Quantity and Quality’).

Factors That Affect the Strength of Gluten

In addition to the quality and type of flour, several other factors influence the strength of gluten. The most significant factors include:

  • The hydration of the dough.
  • The degree of kneading and dough oxidation.
  • The degree of fermentation.
  • The presence of protease enzymes in the dough.
  • The presence of additional ingredients in the flour or dough, such as various types of dough improvers.

The minimum hydration level necessary to fully utilize the gluten potential of most flours (meaning to achieve full gluten development), is approximately 55%.

If the hydration level is below 55%, the flour will not absorb enough water to reach saturation;. And since water is essential for gluten development, using low hydration will restrict gluten development in the dough.

Certain baked goods, such as crackers, cracker style pizzas, pie crusts, and scones, require minimal gluten development (also achieved by using low hydration) to achieve a specific texture, such as crispiness or crumbliness.

On the other hand, using a hydration level higher than 55% will generally allow for the full gluten potential of the flour to be utilized.

Kneading also affects the elasticity of gluten. Insufficient kneading leads to a dough with limited elasticity, while excessive kneading (over-kneading) can result in a sticky dough that stretches too much and lacks elasticity. A dedicated post about kneading will be published in the future.

Ingredients that strengthen gluten include salt, milk, and acidic ingredients with a low pH, such as vinegar or buttermilk. Conversely, ingredients that weaken gluten are fats, sugar, basic ingredients with a high pH (like baking soda), and starches added to flour (such as rice or potato starch). The more of these ingredients are present in the dough, the more significant their impact on gluten. Additionally, various dough conditioners can also influence the strength of gluten.

How Does Gluten Affect the Dough and the Final Product?

As mentioned earlier, gluten is responsible for the dough’s ability to expand in volume, both during fermentation and in the oven spring phase of baking. In general, the higher the protein (gluten) content of the flour, the greater the potential volume of the baked goods.

Furthermore, the method of kneading (how the gluten was developed), as well as the dough’s elasticity and extensibility at a given moment – both have a significant impact on the final product.

The more elastic the gluten in the dough is:

  • The dough will maintain its shape better and will not ‘spread’ to the sides.
  • The dough will be stiffer and resist more, making it difficult to stretch and causing it to snap back to its original shape, similar to a rubber band.
  • A more elastic gluten at the time of baking results in a final product that is tougher and chewier, with a more compact crumb structure (less airy).

The more extensible the gluten in the dough is:

  • The dough is less likely to keep its shape and may ‘spread’ to the sides.
  • The dough will be softer, more extensible, and will stretch more easily.
  • A more extensible gluten at the time of baking results in a final product that is softer with a more open crumb structure (more “air pockets”).
  • A dough that is too extensible may not be able to withstand the pressure during baking, which could potentially result in collapsed gluten (“spiderwebs” in the crust) or the formation of large holes/air pockets in the crumb (pita-like results).

Reaching a balance between extensibility and elasticity is an important aspect of the art of baking, whether it is for general baking or specifically for pizza. When making pizza dough, the ideal dough is one that is more extensible, allowing it to be stretched into a pizza base; On the other hand, when baking bread, a dough with more elasticity is preferred because it helps the dough maintain its shape during fermentation and baking, and also leads to a larger loaf volume.

The extensibility and elasticity of the dough can be controlled by timing the shaping/balling of the dough before baking. The closer the shaping/balling is done to the baking time, the more elastic (and less extensible) the dough will be; For example, if a dough is fermented for a total of 10 hours, shaping/balling it two hours before baking (after 80% of the fermentation time) will result in a more elastic dough, compared to shaping/balling it five hours before baking (after 50% of the fermentation time).

In addition to the above, the degree of extensibility and elasticity of the dough can also be controlled through the kneading method.

Posts about both of these topics will be published in the future.

Biochemical Gluten Development

It is important to note that gluten continues to develop, strengthen, and become more elastic during fermentation, especially during long fermentation. This process is referred to as biochemical gluten development. To learn more about biochemical gluten development, please refer to the following article: Biochemical Gluten Development: The Key to Perfect Pizza Crust.

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