Perfecting the baking process
August 1, 2013
by Shane Whitaker, Baking & Snack
Efficiency, quality, reliability and flexibility are the central characteristics regarding the latest advances in ovens. Bakers seeking the newest in oven technology at this fall’s International Baking Industry Exposition (IBIE) at Las Vegas shouldn’t find any shortages of developments. Many innovative features have been introduced in recent years.
When checking out ovens at Baking Expo, “the first thing bakers must ask is, what style of oven do they need to give them the bake results they desire?” said Ken Hagedorn, vice-president of sales and marketing, Naegele, Inc. Bakery Systems, Alsip, IL, which represents the Kaak Group, Terborg, The Netherlands. “There are so many different styles of ovens — indirect-fired, direct-gas-fired, impingement, cyclotherm, thermal oil — and then, there are hybrid ovens that can combine the different styles into sections. The key is to decide what kind of oven they want and what kind of profile they want for the product.”
Not only are the types of heating systems used in ovens diverse, but their formats also vary greatly. They include rack, deck, tunnel and s-path to name just a few.
Know what to ask
One thing for certain is that an oven must meet the bakery’s desired bake times and quality. In addition, bakers seek faster changeover times. Other key concerns include ease of maintenance and sanitation, and because of food safety and allergen issues, cleanability takes on much greater significance than in the past.
“Bakers today look for energy efficiency, quality of bake and flexibility,” summarized Amanda Hicks, co-CEO of Auto-Bake Pty., Hornsby, Australia, represented in the US by Dunbar Systems, Lemont, IL.
The questions that Cindy Chananie, president of Cinch Bakery Equipment, Clifton, NJ, said she expects to hear at IBIE include: “How flexible is your technology? How even are the bake results? How efficient is your oven? How economical is your oven?” Cinch represents Gashor ovens from Zizurkil, Spain, and while this year represents the first time they will be shown at IBIE, Ms. Chananie noted that the company is not exactly a newcomer.
Bakers must ask about available features that will benefit their operations, advised Phil Domenicucci, executive product manager, thermal systems at AMF Bakery Systems, Richmond, VA. For example, they should want to know how an oven will improve product quality, resulting in a more even bake, stronger ovenspring and better color consistency. And they should inquire about energy consumption and tracking.
While these qualities will lead to a quicker return on their investment, bakeries also must understand that “ovens are long-term investments that are expected to be productive for decades,” Mr. Domenicucci added.
Efficiency reigns supreme
Energy efficiency tops many bakers’ list of desired oven qualities. Since the last IBIE, oven manufacturers have made many strides in the area of reclaiming heat and using it in various processes.
To save energy, they’re reheating the already heated air rather than using cold outside air in the ovens. By capturing and reusing heat, Heat and Control, Hayward, CA, can improve its spiral ovens’ efficiencies. The captured heat can be used to pre-heat combustion air for greater fuel efficiency or to heat water for use in processing and sanitation, noted Don Giles, director of sales, processing systems.
AMF’s Emisshield nano-emissive oven technology employs a NASA-developed, thin-film, nontoxic ceramic nanoparticle material with high emissivity and heat re-radiation capabilities. “In baking, Emisshield systems improve the uniformity and waveband width of the infrared (IR) heat produced by the gas oven,” Mr. Domenicucci said.
By broadening the total bandwidth of the IR radiation from natural gas, Emisshield makes use of more radiation in the useful IR baking range. Therefore, when the walls, pans and burners of an oven are coated with Emisshield, radiant heat is absorbed and then reradiated back to the bread baking in the pans, resulting in more efficient heating of the bread. “This increase in re-radiation yields product improvements such as greater ovenspring, more even heat distribution in the dough and greater color uniformity,” he added.
This technology increases the overall efficiency of the oven allowing energy savings, production increases, reduced air emissions, reduced downtime and maintenance, and improved product quality, Mr. Domenicucci said.
To enhance the energy efficiencies of its ovens, Stewart Systems Baking, Plano, TX, uses impingement recirculating systems to redirect heated air to the oven’s burner-free areas, thus assisting with pan heating and product coloring, noted Dave Machette, the company’s sales and marketing specialist. “This moist air is then exhausted from the oven to minimize flame quench and allow better humidity control,” he explained. “The result is maximum efficiency with a modulated baking profile throughout the baking process.”
Stewart introduced BiVex, an optional oven air recirculation system. This impingement recirculation system enables recipe-driven, customizable directional airflow on the upper and lower pan surfaces, in any desired ratios, Mr. Machette said. “The BiVex System increases efficiencies with the use of air impingement to reduce bake times while maximizing versatility in product bake and coloring,” he added.
Mecatherm, Barembach, France, offers its first oven with Bottom Bake Booster. It bakes breads using convection with air moving under the bread to bake the bottom, while the top and sides are baked using radiant heat. This heating system is available in its FTM three-deck tunnel oven, which can bake products either on the hearth itself or in trays or pans to produce either fully or par-baked bread products.
By controlling how and where heat is applied, bakers can control crust thickness using the FTM oven. In fact, they can create sandwich breads with a very fine top crust but a solid crust on the bottom, according to the company.
Baker Thermal Solutions, Clayton, NC, worked with bakeries to implement active exhaust technology, which aids overall oven efficiency as well as bake quality, according to Jerry Barnes, the company’s senior vice-president, engineering. This system is available as an option on new ovens or can be retrofitted in a stand-alone fashion. “Further, our engineering team is partnering with key providers of heat recovery systems,” he said. “We aim to move beyond simple recovery of sensible heat to tap into more of the lost energy.”
Auto-Bake Serpentine ovens offer significant energy saving advantages through its small s-path footprint and surface area as well as its onboard energy monitoring system, Ms. Hicks said. “Auto-Bake direct-fired ovens modulate energy use based on demand, thus saving energy costs,” she added.
To save energy, oven downtime software from Reading Bakery Systems, Robesonia, PA, reduces the oven to low fire during prolonged production breaks. “Our customers are actively exploring ways to be more energy efficient, and we continue to design systems to help,” said David Kuipers, the company’s vice-president of sales and marketing. He noted about a half-dozen technologies that assist these efforts, including employing heat exchangers and convection baking when appropriate.
“Installing fuel flow meters to record fuel usage during a production shift helps determine actual product cost per kg and helps identify opportunities for improvement in fuel usage,” Mr. Kuipers added.
Den Boer Baking Systems’ Multibake ovens use a “green tool” to avoid unnecessary energy losses and monitor the energy usage for each component, said Martijn Oosterwegel, sales manager of The Netherlands-based manufacturer. Energy management and heat recovery systems for Multibake tunnel ovens, represented in the US by Tromp Group USA, Dacula, GA, provide cost savings, plus improvements in oven efficiency and effectiveness. Heat recovery systems could be implemented for preheating the burner air supply or to preheat boiler water serving the proofer and central water heating system.
Oven manufacturers have also given greater attention to insulation to improve overall efficiency, according to Mr. Hagedorn. For example, previously ovens often would be on legs so sanitation workers could clean underneath them. “But now bakeries will often enclose that area so you can retain some of that lost heat,” Mr. Hagedorn explained.
To make ovens more energy efficient, Terry Midden, industry manager at CPM Wolverine Procter, Horsham, PA, suggested a three-pronged approach. “First, it is important to maintain the oven at its highest operating level — fans, burners, controls, and feed and discharges must all operate properly. Seal all leaks, fine-tune all components, make sure the oven is well-insulated,” he suggested. “Second, make sure the operating parameters are maximized and that the oven is not losing energy needlessly. Third, heat recovery techniques can further reduce energy usages.”
Delivering superior results
Bake times and quality represent primary concerns addressed by equipment manufacturers. Oftentimes, bakeries look to raise their throughputs without increasing the size of the oven. Fortunately, according to Charles Foran, chairman of C.H. Babb Co., Raynham, MA, bakeries today can get 30 to 35% more throughput in the same floor space, an extremely profitable move.
Today’s technology also permits bakers to adjust oven temperatures by 100 to 150 F° in only a couple of minutes, Mr. Foran said, which increases a bakery’s versatility and improves changeover times. Many bakeries don’t know what products they may be baking six months down the road, and these ovens give them the flexibility to do almost anything they want.
The oven manufacturing company also installs vision systems at the exit of ovens to perform quality checks on products, he added. C.H. Babb will show this technology at IBIE, and Mr. Foran noted that new industrial control systems help to tie the vision systems with upstream equipment should product be out of spec as it leaves the oven.
Baker Thermal’s latest tunnel oven design offers Advanced Oven Process Control, providing more control points for a given recipe. This, in turn, gives broad flexibility to users running a variety of products in a single oven and affords faster changeovers, Mr. Barnes said.
Multiple burner towers and turbo convection, both standard features of the Gashor Rocket tunnel oven Cinch will feature at IBIE, give bakers control over the baking profile for greater versatility. “The Rocket comes with multiple burner towers, depending on length, and this makes the bake curve flexible,” Ms. Chananie said. “If your tunnel oven is 100 ft long, maybe the baker prefers to have one temperature at the infeed, another in the middle of the oven and another toward the end. Now, the baker controls the baking profile.”
Multiple burner towers also result in energy savings, she said, pointing out that none of the burners need to work at 100% power. Turbo convection can be engaged or disengaged, depending on the product, allowing the operator control of final baking results. Ms. Chananie also pointed out that the oven is built using a modular construction system. “The length of a Rocket tunnel oven can be from 41 to 147 ft, providing anywhere from 242 to 968 sq ft of baking surface,” she said.
Ovens that feature both convective and radiant heat transfer provide the versatility many baked snack processors require, Mr. Kuipers noted. “They want to be prepared for the widest range of products as well as anticipate new product needs in the future,” he said.
With the latest AMF technology in product tracking, burner control and energy management, Mr. Domenicucci pointed out that changeover times are significantly reduced without affecting product quality.
Bakeries continually strive to improve the quality of their products, and today’s new ovens can go a long way in helping them to do that more efficiently and with greater versatility.