Attaining the best bake
Feb. 1, 2013
by Shane Whitaker
Consumers want variety, and processors must answer this challenge. That’s why bakers and snack manufacturers rely on myriad baking options, including tunnel, decks, conveyorized, serpentine, rack, hearth, direct- and indirect-gas-fired, thermal oil, convection, impingement and hybrid ovens. And then there’s the matter of baker’s preference.
Focusing on flexibility
When considering new equipment, snack manufacturers often express concern about versatility, according to David Kuipers, vice-president of sales and marketing, Reading Bakery Systems, Robesonia, PA. “They want to be prepared for the widest range of products as well as anticipate new product needs in the future,” he said.
To achieve this goal, baked snack processors can rely on a combination of convective and radiant heat. “There are several means of delivering radiant heat to the product in a snack oven: traditional direct-gas-fired burners, direct-gas-fired radiant panel burners, patented SMART Zone radiant tubes and electrical radiant elements,” Mr. Kuipers explained. “When configured within convection baking, these can offer the greatest amount of baking flexibility.”
Impingement recirculated air ovens can bake products ranging from pizzas, flatbreads, cakes, pies and muffins to breads, rolls and baked snacks, according to Bill Foran, president of CH Babb Co. Impingement represents just one of the eight tunnel oven technologies the Raynham, MA-based company manufactures.
The biggest challenge for the modern industrial baker is baking high-quality products at the lowest cost, said Amanda Hicks, director and co-CEO, Auto-Bake. “To stay competitive, bakers are increasingly converting to highly automated continuous production systems that offer minimal changeover time and high yield; this retains the flexibility to manufacture a wide range of products,” she added.
The Australian-based manufacturer, represented in the US by Dunbar Systems, Inc., Lemont, IL, offers its Serpentine ovens that convey pans through multiple horizontal levels in an S-shaped path, saving space in plants. “The high level of automation not only minimizes cost, but ensures repeatable results because all aspects of the baking system such as zone temperature, line speed and air velocity are maintained in the menu of the industrial PC,” Ms. Hicks said. “It is no longer necessary for line operators to have baking skills to ensure high-quality product on a continuous basis.”
Consistency is another huge challenge, noted Scott McCally, mechanical engineer, thermal systems, Stewart Systems, Plano, TX. “Monitoring and feedback at critical points are key to quickly identifying a downward trend before any product is lost,” he added.
A new technology from this company is its BiVex dual-air oven recirculation system that independently controls top and bottom forced-air convection in the curves of the oven. “This advance provides greater control of crust, color and moisture content for the ever-growing variety of products,” Mr. McCally said.
Improved sensor and control technologies benefit ovens’ energy consumption, noted Andy Sharpe, product director for food and feed at Buhler Aeroglide, Cary, NC.
Advanced oven process control from Baker Thermal Solutions, Clayton, NC, adds more checkpoints to regulate a given recipe. “This, in turn, gives broad flexibility to users running a variety of products in a single oven and affords faster changeover,” said Jerry Barnes, the company’s senior vice-president, engineering.
Enabling energy efficiency
The future of baking and oven technology will undergo radical changes over the next decade, Mr. McCally predicted. “Higher speeds, more product variability and lower costs will continue to dominate our marketplace,” he said. “Beyond that, I see bakeries moving toward cogeneration where they begin to really increase their overall energy efficiency across the plant. By taking fuel — generally natural gas — and converting it into heat and electricity onsite, they become energy producers, and their net energy consumption efficiency can improve by as much as 50%.”
Auto-Bake’s Serpentine oven design offers energy-saving advantages through its smaller footprint and surface area and its on-board energy monitoring system. Compact serpentine ovens will provide energy savings of at least 30% compared with legacy systems, Ms. Hicks said.
Baker Thermal is working with a number of bakers to implement active exhaust technology that will aid overall oven efficiency and bake quality. “This system is available as an option on our new ovens, and it can also be retrofitted in a standalone fashion for our installed base,” Mr. Barnes said. “Further, our engineering team is partnering with key providers of heat recovery systems. We aim to move beyond simple recovery of sensible heat to tap into more of the lost energy.”
By enabling bakers to track energy usage trends, AMF Bakery Systems, Richmond, VA, helps them become more sustainable regarding energy consumption. It added energy management options to track energy per pound of product baked, noted Phil Domenicucci, thermal product manager. The oven manufacturer applied newly designed ribbons in its burners for a more efficient gas-to-air mix.
Additionally, AMF can assist bakers in reducing energy consumption and increasing capacity of their ovens by using a nano emissive coating inside the ovens. Emisshield broadens the total bandwidth of the infrared (IR) radiation generated by natural gas as it burns, Mr. Domenicucci said. “Emisshield makes use of more radiation in the useful IR baking range,” he explained. “This results in two different complementary advantages. First, the baker can reduce the amount of energy needed to bake, thus saving energy. Or the baker could increase the capacity of an existing oven, also saving energy. In either case, sustainability significantly increases.”
Modulating and modular
Tunnel ovens with independent zone control for moisture evacuation feature excellent radiation characteristics, allowing bakers to adjust moisture retention during baking, noted Mark Rosenberg, president of Gemini Bakery Equipment Co., Philadelphia, PA.
Gemini’s indirect-fired ovens with multiple baking zones are equipped with true vertical turbulence zones that provide maximum flexibility for specialty bread and rolls.
Modulating gas burners on its direct-gas-heated ovens ensure flame intensity that automatically adjusts to the capacity required for energy-efficient baking, according to Martijn Oosterwegel, sales manager, Den Boer Baking Systems BV, represented in the US by Tromp Group USA, Dacula, GA.
The company implemented IR burner technology on its Multibake modular ovens to maximize the efficiency of the direct-heated and hybrid ovens. “Because the infrared gas heating technique transfers heat rapidly and penetrates quickly into the core of the dough, it is ideal for very short bake processes such as flat or crisp breads, pizzas and pitas,” Mr. Oosterwegel said. “It is also used to heat up the belt, bread straps and lids from the bottom in the first baking zone.”
Its ovens also use a “green tool” to avoid unnecessary energy losses and monitor the energy usage for components. “The Multibake I, using the impingement principle, is unique in that hot air is transported at high velocity to the top and bottom of the product to achieve lower baking temperatures and reduced baking times in a smaller, energy-saving oven,” stated James Cummings, president of Tromp Group USA. The modular layout allows bakeries to reuse waste heat for the production of steam or hot water.
Hot oxidized exhaust air helps heat the initial indirect-gas-fired zone on Turbo Therm tunnel ovens from The Henry Group, Greenville, TX. Darren Jackson, the company’s COO, noted that companies could reduce energy costs by 17% using this hybrid oven by recapturing energy from the direct-gas-fired zones putting the exhaust through an oxidizer. “You are reburning ethanol, so you have cleaner emissions and are able to heat the first 20 ft of the oven,” he added.
Turbo Therm direct-gas-fired tunnel ovens feature individually controlled burners above and below the hearth for even heat distribution. “Multiple thermocouple sensors determine bake chamber temperature and provide zoned temperature control for complete flexibility,” Mr. Jackson noted.
Spiral ovens also feature space-saving designs. Heat and Control, Hayward, CA, manufactures spiral ovens that evenly distribute heated air across the width of the product conveyor on all tiers top to bottom. “Unlike ovens that distribute air from one side of the spiral conveyor to the opposite side, Heat and Control’s design continuously circulates air in an even 360-degree pattern around the entire spiral conveyor for uniform processing,” said Doug Kozenski, sales manager, processing systems.
Its AirForce impingement tunnel oven distribute air at velocities from 2,000 to 9,000 ft per minute across the full belt width to ensure even and controllable baking of a variety of baked goods. “The highly controllable airflow allows for rapid baking and excellent color development,” Mr. Kozenski added.
Indirect-gas-fired impingement tunnel ovens from CPM Wolverine Proctor, Horsham, PA, give processors the highest level of heat transfer and heat treatment uniformity, according to Terry Midden, industry manager. “Uniform heat treatment lowers operating costs, increases product quality and decreases scrap,” he said.
Ovens function as the essential processing system in making baked goods and snacks; therefore, equipment manufacturers continue to focus on this technology to ensure they meet the industry’s needs for dependable and repeatable results.