Mixing dough for bread dates back thousands of years, but the research community still strives to perfect the process in order to improve efficiencies, increase output, decrease energy usage and save money.

“When bakers mix dough for breads and rolls, there are three overall objectives,” says Kirk O’Donnell, vice president of education, AIB International, Manhattan, Kan. “There must be uniform incorporation of ingredients, proper hydration of dry components (fl ours and grains hydrate more slowly than sugar) and the development of gluten.

“If all of the ingredients are placed in the mixer at one time, the uniform incorporation of ingredients is never a problem for bread and roll dough. However, at times certain ingredients are delayed, and when this occurs, incorporation of ingredients may pose some challenges.”

CALLING THE TIME AND TEMP.

Bakers may elect to delay a portion of the water, salt, yeast and all or part of the shortening or other inclusions.

Water temperature is important to the mixture, as it controls the ultimate temperature of the dough. Most commercial bakers use jacketed mixers that circulate some refrigerant, such as glycol, as near to the dough as possible to regulate the temperature of the dough. At times, ice is used. In any case, the desired dough temperature at the end of mixing, the temperature of the added water, the amount of water in the formula (based on bakers’ percentage), the temperature of the mixing room and the temperature of the fl our all must be factored in when creating dough. The friction factor, or the amount of heat created by the mixing process, needs to be determined. The friction factor varies from mixer to mixer and with differing mixing times. The friction factor must be re-established when any parameters of the process are changed. Water acts as a lubricant in the dough and can reduce the friction required to develop gluten. It may be necessary to add water in increments to ensure gluten is formed before all the water is added.

This is why there is sometimes a delay in adding shortening to the mix. Formulas that require shortening totaling more than five percent of the fl our weight should specify that any shortening exceeding that threshold be delayed.

By incorporating salt into the dough later in the mix, bakers can reduce the energy output needed to make the dough. Salt will toughen the gluten, O’Donnell says, “and more mechanical (mixing) time will be needed to develop the gluten. If salt is added later, mixing time can be reduced by 10 to 15 percent, and the frictional heat can be reduced. Salt must also never come in direct contact with yeast, as osmotic pressure will dehydrate the yeast cells and kill them. Bakers sometimes delay the yeast, especially if they are using instant yeast. THe only reason for this is that the instant yeast should not come in direct contact with ice, very cold water or refrigerated surfaces of mixers.”

Proper hydration is essential for good-quality finished products. Sugar hydrates faster than fl our and whole wheat, while whole grain ingredients hydrate slower than white fl our. Bakers must adjust formulas to incorporate these varying parameters. Slower mixing speeds promote hydration, while faster mixing speeds promote gluten development.

GLUTEN DEVELOPMENT

“The last mixing objective for bread and roll doughs is the need to develop the gluten. Wheat as a grain has a unique ability to form a gluten network, which occurs when fl our is combined with water and energy,” O’Donnell says. The USDA’s Agriculture Research Service (ARS) has isolated wheat proteins other than gluten that also affect the mixing process. Gliaden, glutenin and the water-soluble protein albumin have been found to be as essential in forming a good loaf of bread as gluten. The time needed to develop gluten is determined not only by the amount of protein in the fl our (strength of the fl our), but also by the speed of the mixer. The faster the mixer, the less time it takes.

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