The mysteries of mixing
Finding the right mixer takes research and knowledge of your product line. Knowing your mixer needs will enable you to choose the right machine.
“Mixing is the most important part of the entire dough making process,” says Noël Haegens, owner of Classo Foods and senior baking technologist, Tate and Lyle, London. The mixing process shears, stretches and kneads the dough to incorporate all the ingredients uniformly. “If the dough is undermixed or overmixed, you will notice it in the handling qualities of the dough,” he says. The mixing of the dough has a number of objectives: to incorporate all the ingredients uniformly, to hydrate the flour and other dry ingredients and to develop the gluten. Gluten development results from a combination of water, flour and energy.
Four types of mixers are commonly used in the baking industry: spiral, planetary, horizontal and oblique mixers. Each mixer offers unique functions.
“Spiral mixers, in my opinion, are the most versatile machine available for the bread baker today,” says Michael Eggebrecht, bakery consultant and a representative of WP Bakery Group, Shelton, Conn. Spiral mixers can handle a wide range of dough capacities, with many able to go as low as 15 percent of overall capacity. They also can mix in reverse, which is ideal for adding ingredients at the beginning of the mix, as well as inclusions, such as grains, raisins, nuts or olives, at the end of the mix.
What drives the bowl also should be considered. Some companies offer a gear-driven bowl, while others offer friction wheels to turn the bowl. Friction wheels will wear out over time, while the friction of metal against metal in a gear-driven bowl may eventually affect the motor. Bakers must decide which system is best for their operation.
“The most important thing to look for,” Eggebrecht continues, “is that the spiral mixer itself has very close tolerance between the spiral hook and bowl. Some do not have close enough tolerances, and many times this results in an uneven incorporation of the dry ingredients, and some flour can be left on the bottom of the bowl.”
John Squire, district manager, Kaak Group North America Inc., Lithia Springs, Ga., agrees that spiral mixers are the best for most applications but cautions that not every spiral mixer has the same rotational speed, and those with a small spiral tool may need additional breaker bars to reduce mix time because the spiral will not grab enough dough. Longer mixing time may increase dough temperature, which must be lowered by adding cold water or ice. Additionally, the smaller spiral equipment may torque out as dough stiffens.
Planetary mixers are typically used in foodservice or other small bakeries and are not ideal for bread production. “Planetary mixers typically generate more heat in the dough, and they require more scraping to ensure that all flour and dry ingredients are incorporated properly. Most of the time, the mix time needs to be increased compared to a spiral mixer,” Eggebrecht says.
Horizontal mixers also are not recommended for the production of high-quality hearth bread, Eggebrecht says. However, they can be used if that is all a bakery has available. “Great care must be taken to ensure that mix times are adjusted, and the doughs are carefully monitored to achieve the right consistency,” he advises.
Oblique mixers or fork mixers are often used in France for producing high-quality hearth bread, although a few U.S. bakeries use them as well. The oblique mixer's actions mimic the motion of human hands. “The main disadvantage of an oblique mixer is that you must fill the mixing bowl to at least 50 or 60 percent of the overall capacity so the mixing action can turn the bowl,” Eggebrecht says. “The bowl is driven off the friction created from the dough against the sides of the bowl, and without a continuous dough ring around the bowl the mixer will not rotate properly. Additionally, mix times are often longer than when using a spiral mixer.” He recommends using an oblique mixer for producing white lean breads, such as French baguettes and ciabatta.
One of the newest mixer models is the Wendel, which features twin stirrup-shaped dough hooks designed to offer more complex kneading action. It reduces mix times and offers the possibility of up to four percent more water absorption. The mixer can be used for all dough types, from heavy wheat dough to delicate puff pastry.
The importance of ingredients
Along with the mixing equipment, other critical components of the mixing process are the ingredients themselves.
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