A new fix for the mix
Feb. 1, 2014
by Charlotte Atchley
When developing a dough or batter, whether it’s for bread, buns, cookies, cakes or bars, one thing is for certain: The more efficient the mix, the more time and money bakers save. Efficiency doesn’t always equate to the fastest RPMs. Rather, it ultimately balances the time of dispersion with product quality as well as the cost of running the equipment.
Of all the steps in baking, mixing is one of the most straightforward. There is a bowl and an agitator. Ingredients come in and are dispersed. Dough is formed. By implementing the proper machine, tools and process, however, bakers can impact the quality and speed with which their ingredients come together to create that perfectly consistent dough. This is most important because while mixing may seem simple, what comes out of the bowl affects the entire operation and ultimately the finished product. Greater automation, enhanced cooling methods, pre-absorption and blending along with energy savings can all make dough development a more rewarding step for producers of all baked goods and snacks.
Mixing before the mixer
The goal of improving baking technology is always to heighten the final product’s quality or enhance the process. A more efficient mix means savings in time, energy and money with a more consistent batter or dough being discharged from the bowl.
Mixing comes with an assortment of challenges from energy spikes to heat generated by the friction in the bowl. One way that bakers can address these challenges is by incorporating pre-absorption or pre-blending of ingredients before the final stage of the process.
This technique not only saves bakers time and money on the process, but it also improves the consistency of the dough and finished product. Pre-blending and pre-absorption — whether through time-tested sponge systems and liquid brew methods or by newer technologies — can cut down on the amount of time and work needed in the final mixer while offering improvements to the dough.
For yeast-raised products such as bread and pizza dough, pre-hydrating the flour helps eliminate free water, improves yield and extends shelf life. Incorporating as much water into the dough as possible makes costly ingredients go farther, which helps bakers control costs. “It’s a very efficient way to treat your dough better,” said Stephen Marquardt, sales director of North and South America, Zeppelin Systems USA, Odessa, FL. “It means you have more flavor, and you can increase your shelf life.”
Bakery Concepts International, Mechanicsburg, PA, represents Rapidojet technology in the US, Israel, and Central and South America, a continuous or batch technology that combines liquid ingredients with free-falling dry ingredients, which bakers can use to either pre-hydrate their ingredients or fully develop them as they would in the final mixer. According to Ken Schwenger, president of Bakery Concepts, dry ingredients in vertical free fall combine completely with liquids under high pressure to form fully hydrated minors or a homogenous dough with higher hydration that requires less time and energy than conventional methods. Pre-hydrating the flour, Mr. Schwenger said, can slash final mix times by more than half, increase total yield by about 9% and result in less damage to the dough.
“The final mixer is just incorporating all the minor ingredients,” he said. “If you’re fully pre-hydrating, shelf life is measurably increased, it takes less time to mix, does less damage and generates no heat.”
To maximize these benefits, liquids are being added earlier in the process, according to Jim Warren, director of mixing sales, Reading Bakery Systems, Robesonia, PA. Incorporating liquids sooner gets the flour hydration process started more quickly.
Making the right first step
Water absorption isn’t important for every product, however, and it’s vital for bakers to understand the absorption needs of their dry ingredients, Mr. Warren said. Understanding how water and dry ingredients come together helps bakers and snack makers choose the right mixer for their needs. Products based on potato flakes, such as fabricated potato snacks, are a bit too happy to absorb water, so absorption must be kept under tight control.
Flour-based products such as bread and rolls are willing to take on the water but require some effort to force the bond. Other dry ingredients, particularly in the case of energy bars, do not want to take on any water and require a lot of energy to combine everything into a cohesive batter or dough. “It’s the willingness of different raw materials to absorb moisture that makes the pre-blending so important to the mixing step,” Mr. Warren said. “You have to select the right first step in the process to be sure the moisture is getting absorbed by all the dries in a way that you want them to be distributed.”
While absorption may not be of concern for some applications such as cookies, those bakers can still enjoy similar benefits. “Pre-blending the ingredients also requires less work to actually be done in the mixer,” Mr. Warren explained. Combining dry and liquid ingredients separately before the mixing bowl cuts down on time and energy spent bringing all those ingredients together. With less work comes less heat — another variable bakers must contend with when developing dough. These uniform pre-blends coming into the final mixer also are another step toward making the dough consistent every time.
While it seems like a lot of mixing is happening before the ingredients even get to the bowl, the dough still must be developed. Uniform dispersion of ingredients and maintaining dough temperature ensure consistent dough discharges from the mixer into the dough feeder.
Baker Perkins, Grand Rapids, MI, designed its new HS mixer, without a shaft. With this lumbering piece of metal out of the way, ingredients can be dispersed more efficiently, and the dough can leave the bowl hands-free, according to Keith Graham, marketing manager for the company. “The shaft doesn’t obstruct the free flow of dough around the bowl so the mixing can be much more efficient,” he said.
Mr. Graham described a test of the shaftless machine’s capabilities in which chocolate chips were added in one section of cookie dough instead of being spread throughout. After running the blade for 30 seconds, several samples of the dough revealed about 95 chocolate chips were present in every section. “That was great for mixing chocolate chips, but the same technology is also dispersing the fat, flour and sugar at the beginning of the mix,” Mr. Graham explained. Despite not having a shaft to hold it in place, the rigid blade maintains the same clearance of the bowl at all times, making it appropriate for both cookie and cracker dough.
AMF Bakery Systems, Richmond, VA, developed its YT agitator for improved efficiency. According to Bruce Campbell, vice-president, the YT agitator pulls the dough in a different direction as it’s being kneaded and stretched in the bowl. “Instead of stretching it one direction always, it will actually stretch it side to side, making [the process] more efficient,”
Topos Mondial, Pottstown, PA, emphasizes proper mixer configuration with its open-frame, three-roller-bar mixer. It features unique bowl geometry, properly positioned roller-bars at the time of commissioning and the correct RPM settings for the product’s dough absorption. These three elements can cut mix times, maintain dough temperatures and use less energy in the process. “When you are properly configured, you properly knead the dough instead of just sending the dough on a ride around the bowl,” said Damian Morabito, president.
Maintaining dough temperature also means the mechanical forces in the bowl will not amp up the heat of the ingredients. “Consistency comes down to dough temperature and providing consistent dough temperature,” said Terry Bartsch, vice-president sales, Shaffer, a Bundy Baking Solutions company, Urbana, OH. To help with this critical component, Shaffer offers bakers a refrigerated agitator system. Mr. Bartsch said this unit can reduce final dough temperatures between 4 and 6 F°.
Zeppelin Systems USA discovered an added function of pre-hydrated flour. By running its water-and-flour mixture through a heat exchanger, Zeppelin Systems cools the hydrated flour to 35 F° before adding it to the rest of the ingredients in its continuous mixing system, Codos Technology. This helps control temperature spikes in the bowl without having to rely on other refrigeration techniques like ice or CO2.
To improve bowl cooling, Oshikiri Corp. of America, Philadelphia, developed a new jacket style for its horizontal mixers that improves heat transfer. This pass-through system pulls heat away from the dough, transfers glycol through an inlet-outlet system that migrates the fluid side to side within the bowl’s jacket, according to Tim McCallip, general manager.
Yeast-raised dough, being a living product, is less forgiving than cookie dough. The longer they sit around, the more they change. “If you have a smaller batch and it’s coming out more frequently, then it’s fresher,” said Kevin Wilkinson, North American sales manager, Tonelli Group, Parma, Italy. The company’s planetary mixers can do about four batches per hour, twice as many as conventional equipment.
With high speeds, Advanced Food Systems, Columbus, OH, has slashed mixing time. According to Denny Vincent, president, a pizza dough that once took 10 minutes to mix now only needs two minutes in the bowl. These short times enable bakers to run smaller batches more often and maintain a high quality of dough. From ingredient metering to dough discharge, a traditional mixer might take 15 minutes while the Advanced Food Systems unit may take seven to eight minutes. “Now that dough only has eight minutes to get from beginning to end, it doesn’t have much time to change,” he said.
Staying and saving green
More efficiency enables saving energy. “Mixers have the largest motors you’re going to find in the bakery, and with the older two-speed mixers, just turning the machine on you see a huge spike in energy consumption,” Mr. Bartsch said.
Without variable-frequency drives
(VFDs), those motors go from cold to working speed instantly. “The problem with mixers is you put a ton of ingredients into them and then you try to start the blade and what you get is a very high starting current,” Mr. Graham explained. VFDs can reduce the starting current by up
Such drives ramp up the agitator gradually over the course of several revolutions. “If you can start your motors up gradually, it requires a lot less electricity,” Mr. Vincent said. Advanced Food Systems’ fast mixing times also ease the energy demand by running for less time.
VFDs are often standard now, and Topos Mondial includes them on its open-frame mixers. Baker Perkins, Tonelli, and Shaffer all include these drives in their systems.
“Soft-start systems have fewer spikes in ampage, so it’s easier on the equipment and the infrastructure,” Mr. Wilkinson explained.
Topos Mondial couples high-efficiency direct-drive motors with its VFDs. “With these new drives, you use a lot less amps to get the same capacity of dough production for a lot less total energy consumed as compared with the older mixers without VFDs,” Mr. Morabito said.
Oshikiri equipped its horizontal mixers for adjustable RPMs in each part of the process. This system matches the dough development with the proper speed with a four process speed system. This optimizes mixing while improving energy efficiency as well.
Because these machines are such power hogs, blending ingredients in an efficient manner can also save energy costs. Any improvement on mixing times is less time the agitator has to be moving.
Whether batch or continuous, bakers can take steps to meet the needs of their dough. With pre-blending and hydration, as well as proper tools and configurations, bakers can adjust the process to get the most consistent and efficient mix possible, saving them time and money.