CHICAGO — When it comes to wheat, there are many approaches to assessing quality, including protein content, enzymatic activity and even physical properties. What may be high quality for one application may not be for another, making valuation of flour complicated for even the most experienced baker. It is, however, paramount for bakers to be aware of variations from one flour shipment to the next to ensure batch-to-batch consistency.
“Quality and consistency in ingredients are crucial to baking,” said Reuben McLean, senior director of quality and regulatory, Grain Craft. “A main ingredient, such as flour, can affect the operational efficiency of a bakery if the flour characteristics from bag to bag or load to load do not remain consistent. Variability in baked goods can be found in a range of attributes such as tolerance to dough processing, end-product volume, symmetry and crumb structure.”
Consider two different products, both made from wheat flour: the bagel, which has a dense, chewy consistency, and cake with its aerated texture. The bagel and cake are on opposite ends of the spectrum when it comes to sensory attributes, yet the main ingredient in both products is wheat flour, just not the same wheat flour.
Classes of wheat
Wheat comes in six different classes in the United States: hard red winter, hard red spring, hard white, soft red winter, soft white and durum. These are defined by color, hardness and growing season and have a range of quality characteristics that are used for flours. Certain types are well-suited for pastas and noodles while others are more suited for confectionary products.
It’s important for bakers to think about the end result when choosing the appropriate flour.
“Understanding the baking process and recipe formulations of specific products can help bakers choose the appropriate flour for flavor and texture expectations,” said Rob Ostrander, director of technical solutions, Ardent Mills. “For example, whole wheat flour is milled from the entire kernel of wheat, whereas all-purpose flour is produced from the finely ground part of the wheat kernel’s endosperm.
“The presence of bran in whole wheat flour reduces gluten development, causing baked goods to be denser than those made from all-purpose flour.”
In contrast, cake flours tend to be lower in protein and higher in starch, which imparts a delicate texture for cakes and cookies. For bakers, choosing a suitable flour is a crucial step to ensure baked goods meet quality standards.
“Bakers should first identify the texture and flavor profile they are expecting from their baked goods,” Mr. Ostrander explained. “From there, they can evaluate the protein content of different flour options to meet those expectations. Protein content can impact the functional properties of the flour and doughs/batters including water absorption, cohesiveness, dough strength, texture, loaf volume and crumb grain.”
Gluten is an elastic substance that forms when two proteins — glutenin and gliadin — are mixed with moisture. These two proteins bind water and connect and cross-connect to form elastic strands of gluten. These proteins are found in all forms of wheat, including durum, semolina and spelt, as well as other grains, such as rye, oats and barley.
Gluten development is not as important in some baked foods. Therefore, lower protein flours may be used in such applications.
Protein content can impact functional properties of flour when made into dough or batter. Affected properties include water absorption, cohesiveness, dough strength, texture, loaf volume and crumb. But it’s not just protein content that matters; it’s also the levels and distribution of individual protein fractions, mainly gliadin and glutenin, in the wheat, as well as growing conditions and milling method and treatments.
“Achieving quality and consistent flour starts long before the wheat enters the mill,” Mr. McLean explained. “At Grain Craft, we work closely with growers to promote Grain Craft Preferred Varities. These are wheat varieties that have been thoroughly tested and selected based on key milling and baking characteristics. “Wheat quality is largely impacted by two factors: the environment and the genotype, or variety. Grain Craft Preferred Varieties allow us to reduce variability in flour performance even during years where there may be significant environmental challenges.”
The percent of protein content is dependent on the type of wheat milled. It is also the foundation for purchasing but is not a reliable index of the flour’s baking performance. The quality of the protein is genetically determined. In wheat varieties that are grown under comparable environmental conditions, a high-quality wheat will produce good bread over a broad range of protein levels, but a poor-quality wheat will generally result in low-quality bread, even if the protein content is higher.
“Protein quality relates to the flour characteristics that make it suitable for baking,” said Dave Kovacic, technical service, Bay State Milling.
Key characteristics include gluten quality attributes, such as strength during mixing and fermentation, as well as process tolerance. A quality flour has the ability to perform under varied environmental or mechanical conditions. For bread flours, this also includes the ability to bind with and hold water, the strength of the gluten to hold gas and the ability to provide loaf volume.
A bakery might want to change its formula for cost savings, but a change may mean a significant adjustment to the process.
“To achieve the nuances between different types of baked goods, it’s important to choose not only the right level of protein, but also the quality of protein best suited for the product,” said Josh Reasoner, milling technical service manager, ADM. “Cakes and pastries, for example, ordinarily use a soft wheat flour. They will be sensitive to a change in protein, both quantity and quality. The flour included in a cookie, on the other hand, is more of a vessel for the sugars, fat and other elements in the formulation.”
Managing variations in flour quality can sometimes just require small changes to processes or formulation.
“If bakers are thinking about switching flours or looking for flour to meet their new desire quality characteristics, they should reach out to their flour supplier to talk through options,” Mr. Ostrander said. “While that could mean using a new flour product, bakers might also find that small changes to their current process or formulation can make significant differences in the final baked good.”
Experimenting with bread
The formulation for white sandwich bread is a straightforward example to demonstrate how flour’s protein content impacts the finished product. Bakers generally experience success with flour protein ranges between 10% and 11.5%.
“If the protein content is too high, the bread will be too dense and chewy,” Mr. Reasoner said. “Inversely, if the protein level is too low, it will affect the volume and the bread’s internal crumb.”
It’s become quite common for bread bakers to experiment with the addition of grains, nuts, seeds, fruits and fiber additives. Any extras place a burden on the strength characteristics of the flour.
“The clean label movement, as well as the prevalence of organic baking, has eliminated many of the traditional dough strengthening and oxidizing conditioners used in commercial bread making,” Mr. Kovacic said. “The inclusion of other non-gluten forming grains and seeds, fiber additives, as well as whole wheat flour, places an additional burden on the strength characteristics of the flour. Even so, bakers still expect the flour to perform in a similar manner. Now, more than ever, wheat flour needs to be considered a key functional ingredient and not a commodity.”
Artisan loaves with their hearty density and open volume often feature these extra grains.
“Adding ancient grains, depending on which grain and how finely they are milled, might have an undesired effect on the gluten structure of the dough,” Mr. Reasoner said.
Bran, for example, might have a sharp edge that cuts into the gluten matrix and weakens the structure. Using a high protein flour, in the range of 12.5% to 14% protein content, may also assist with building desirable structure and retaining volume after baking. When blending grains for multigrain breads, all-purpose flour may work well as the base, as long as the other grain flours contribute protein as well as fiber for strengthening the dough.
More than protein
The American Association of Cereal Chemists has approved methods for determining various properties of flour that impact performance, and thus are considered indicators of quality. This includes quantification tests for ash, moisture and protein content. In the experience of Scott Baker, principal scientist at The Annex by Ardent Mills, the bake test remains the best identifier for finished product quality and to evaluate flours for performance needs.
In addition to the variations among wheat crops, there are other quality measurements critical to product success. Falling number (FN), for example, is a wheat quality test that measures alpha amylase activity in flour. Alpha amylase is an enzyme found in sprout-damaged wheat. The FN is the time in seconds for a stirrer to fall through a hot slurry of ground wheat. The lower the number, the higher the enzyme activity, which means the more starch that has been converted into sugar. Starch supports structure in many baked foods. Starch degradation results in an inferior product.
“For bread quality, a low FN flour results in sticky dough, darker colors, coarser crumb, and a sticky and gummy bread texture,” said Edward Usset, grain marketing economist, Center for Farm Financial Management, University of Minnesota. “For pasta and noodles made with low FN flour, the resulting product is fragile, soft and mushy.”
The FN can be influenced by starch structure, starch degradation, other non-starch polysaccharides and protein. The US Department of Agriculture Wheat Quality Lab states that an FN greater than 300 is indicative of no sprout damage. A measure between 200 and 300 indicates some sprouting, with less than 200 suggestive of severe wheat damage.
The two main causes of low FN are preharvest sprouting, which happens through the initiation of germination by cool, rainy conditions after the wheat turns from green to gold, and late-maturity alpha amylase, which is the result of large temperature increases or decreases during grain maturation.
Anything but simple
Wheat is a complex grain. It’s no wonder that flour is a fickle ingredient. Bakers need to be able to have the ability to make slight adjustments to the dough absorption and/or mix time at the bowl.
The best way for bakeries to manage natural variations in flour is to have a skilled operator at the mixer who knows how to react in real time, making slight adjustments that ensure consistency. Automation and robotics cannot replace an experienced baker.
“Even the particular sound of a mixer alerts them that something unexpected is happening with the dough,” Mr. Reasoner said. “It might mean adding water or adjusting mix time. It’s important to have someone working the mixer who knows how to feel the dough and recognize whether or not those changes worked or were needed.” Mr. Kovacic added, “It’s also important for bakers to know what treatments, if any, have been added to their flour, and what the function and benefit of each is.”
The type and amount of treatment used by the flour mill will vary with the type and grade of flour and its intended use. Treatments may include enrichment, addition of enzymes, bleaching and maturing agents. Reviewing the Certificate of Analysis is a good first step to determine what adjustments may be necessary.
Every flour will have an optimum absorption and mix time. Typically, an adjustment won’t be necessary, but bakers should have the know-how and the ability to adjust when needed.
“There is an understandable desire for bakeries to pay the least cost for their flour,” Mr. Kovacic said. “Unfortunately, this approach may require additional input costs at the bowl to compensate for a lack of inherent quality. Bakers should talk to their millers to determine if paying more for a different flour may actually in turn reduce their overall cost, which could include savings at the bowl through a reduction of vital wheat gluten, enzymes or dough conditioners.”
A more expensive flour may also improve manufacturing efficiencies and tolerance. Yield increases could be realized if the flour requires higher absorption. This may reduce staling, thereby improving shelf life and reducing waste. Product quality may also improve, increasing sales and reducing consumer complaints.
“Strong supplier partnerships can help manage variations in flour quality” Mr. Reasoner concluded. “A supplier that mills high-quality wheat and grains into flour with top-of-the-line technologies and equipment helps commercial bakeries achieve consistency and reliability. Bakers should be encouraged to discuss their specific flour quality needs with their flour miller.
“Communicating how the flour will be used, and the flour quality characteristics needed, will go a long way in building a trust-based relationship.”