Bakers need more from ovens than ever before. Energy efficiency, heat retention and flexible programming are only a few attributes buyers look for in the latest generation of commercial ovens. Consider every option before purchasing your next oven.
Buying an oven is a complex, expensive and often daunting process. Complex because your bakery’s needs are unique, and daunting because purchasing an oven is probably the most costly equipment investment you will make for your business. In short, oven shopping is not for the faint of heart. By understanding your options, you can find the best possible oven for your business.
The value of experience
Ovens do one thing: bake. That is not to say, however, that all ovens are alike. Tunnel, spiral, rack and deck systems, hearths–there’s an oven out there for you, no matter what product you bake.
Mike Ward, chief manufacturing officer and senior vice president for Brea, Calif.-based Fresh Start Bakeries, which bakes hamburger buns and English muffins for McDonalds, has spent 45 years in the commercial baking industry and has seen the evolution of ovens firsthand. When he started, flash heat was one of the biggest obstacles to turning out consistent products.
“When you had an oven that was completely full, it worked pretty well, but whenever there was a gap in the run or you were changing products, you’d get flash heat,” Ward says. “The more varieties you were baking, the bigger the problem. So, we came up with flash pans, ordinary baking pans that we filled with water and sent through the oven between runs.” The pans minimized flash heat, allowing for greater consistency and avoiding flash burn, but bakers had to manipulate the burners continually to maintain consistent oven temperature, Ward adds.
|Stewart Systems recently rolled out its Solstice line of tortilla ovens, which feature individual burner controls, pilot-less burners and advanced heat retention technology.|
|Hybrids, such as this Spooner Vicars oven, combine direct gas-fired heat at the front of the oven with convection heat at the back.|
|Vertical ovens are an option for bakers looking to increase capacity but lack additional floor space.|
|AMF’s direct gas-fired Vesta Tray Ovens improve product baking consistency and reduce energy consumption.|
Automation has all but eliminated these problems. “New oven computer systems do all that for you,” he says. “They manipulate the oven automatically. They also monitor humidity. If the oven air is too dry it can cause cracking and breakage. If it’s too wet, you get blotchy products.”
Fresh Start is completing production on a bun and muffin bakery in Ontario, Calif. and installed two BakeTech spiral ovens at its new facility. Fresh Start’s relationship with BakeTech dates back to the early days of oven automation. “They started coming up with electronic features that sense gaps in the line and lower the burner flames or open the damper to exhaust heat, which lowers the oven temperature,” Ward says.
BakeTech ovens’ automation has kept pace with customers’ increasingly exacting standards, Ward adds. “Nowadays, the customer wants that perfect color and consistency in every single piece,” he says.
Controlling the environment
Modern oven control panels are both product sensitive and user friendly, allowing operators to program all of their formulas for near-turnkey results. Ideally, an operator specifies the product, and the system automatically adjusts the heat profiles accordingly. Unforeseen variances in oven temperature can occur, at which point an alert is sent to the operator, who manually adjusts the profile. Most control systems on the market today can be controlled remotely via modem. Many have multi-lingual capabilities as well.
Jamie Douglas, sales director, Spooner Vicars, says the Carrollton, Texas-based company’s “non-operator” system is essentially an automatic oven because all systems are programmable through the PLC (programmable logic controller). The latest developments in oven programming are automatic humidity control and full-color vision systems that monitor bakery products for color, shape and volume. Feedback is provided to the oven in real time. “Whatever it needs, the system will control the oven to suit,” Douglas adds. All Spooner Vicars ovens are available with modem links, so if a problem arises at the bakery, the manufacturer can modify the program online.
Keeping the heat
Keith Dietz, conveyorized products manager for Plano, Texas-based Stewart Systems, concurs that today’s buyers are looking for ovens that perform far above the level of their predecessors. “With gas prices going up, customers are asking for more efficient ovens,” he says.
Stewart Systems offers a line of continuous-style ovens that employ unimixers, which combine gas and air. The mixture is then blown into ribbon burners that completely cover the pan path. The advantage of continuous ovens, Dietz says, is that products travel through the oven one pan at a time, allowing the operator to set up heat profiles that are uniform and consistent throughout the run.
Dietz notes Stewart Systems is constantly “studying the efficiency of our ovens and gas meters, and working with bakeries to monitor their performance in order to validate and quantify their efficiency, and possibly, allow us to reduce the number of burners we put in our ovens.”
Heat retention is a major factor in optimizing oven efficiency, Dietz notes. “Our ovens have 6-in. panels filled with 8-lb. density mineral wool on three sides and 3-in. panels on the floor. We also minimize the size of the openings in and out of the box so we don’t lose much heat,” he says.
“Inside the oven, we use burners down the straights in the middle of the oven. Then, we use a recirculation system that draws oven heat over the top of the burner,” Dietz adds. “Circulation fans draw the heat in, and it is blown through tubes onto the bottom of the pans on each end of the oven, which gives us some convective heating of the pans. The fact that we’re using that same air twice, through radiant heat and forced convection, makes for very efficient ovens.”
Stewart Systems recently charted new territory with the unveiling of its Solstice flour tortilla oven, which features a throughput of 2,400 tortillas per hour. The oven features individual burner controls, pilot-less burners and advanced heat retention technology. The insulation system keeps the exterior of the oven cool during operation. The heat isolation design lengthens the lifespan of bearings and motors, reducing maintenance costs and downtime, the company says.
Maintaining the equipment
Maintenance issues, particularly those involving the oven chain, are of primary importance to any oven system. Stewart Systems addressed this by installing automated stations for cleaning and lubricating the chains in its ovens. The air blow-off feature “aids in removing particulate matter from the chain before it hardens and becomes debilitating to the operation of the oven,” says Bryan Mannion, marketing manager, Stewart Systems.
“The most important thing to any piece of equipment in a bakery is how it is maintained, and those systems, when properly used by the bakery, can ensure proper chain maintenance,” Dietz adds. “When you’re running lubricants through a system that’s so hot they begin to move from viscous lubricants to hard deposits, that’s what our system is designed to remove before they lock up a bearing or become detrimental to the track that the chains run inside of.”
Choosing the right style
Most ovens available today feature a high degree of automation, good heat retention, energy efficiency and flexible, user-friendly controls. But what oven is best for your bakery?
If you will be using the oven to bake a wide variety of products, consider the versatility of rack and deck ovens, which work equally well for bread and sweetgoods.
Tray and tunnel ovens also offer a great deal of flexibility for baking hearth breads, as well as pan breads, rolls, bagels and even sweetgoods.
MIWE offers the Thermo-Rollomat multi-level tunnel oven, which features added versatility. “We have the advantage of being able to do what a tunnel oven can do, plus short runs,” says Harry Jacoby, president, MIWE America, Hillsborough, N.J.
The high capacity oven can be customized with two to seven decks. The oven uses thermal oil heating and functions as a stack of tunnel ovens, ideal for limited floorspace. Decks run independently of one another, keeping heat profiles separate. MIWE is known for the sophistication of its controls, and the Thermo-Rollomat offers dual programming stations that are placed at opposite ends of the oven.
Many conveyorized tray and tunnel ovens are available in direct and indirect heat models. Direct heat provides the highest energy output because the gas-fire heat source is in the baking chamber, typically ribbon burners. Gas is piped through tubes and ignited at the burner. Direct heat is the method of choice for high-heat applications, such as crackers, pan breads and pizzas.
AMF Bakery Systems, Richmond, Va., offers its Vesta line of gas-fired tray ovens, which improve baking consistency and reduce energy consumption, according to Larry Gore, the company’s director of sales and marketing.
“The baking industry is chock full of old ovens, many of which have been around for 20, 30, 40 and even 50 years,” Gore says. “The baking industry also is full of new ovens with old designs. Although ovens may appear shiny on the outside, their baking chambers and control systems merely are repeats of old designs with slight modifications. However, a new breed of ovens slowly is infiltrating the baking industry. These ovens bake, control and manage energy consumption better than old ovens,” Gore adds.
Indirect heat ovens separate the heat source from the baking chamber. Heat is transferred to bakery products through high-speed hot air or radiant heat. Impingement heating in a tunnel oven bakes products by circulating hot air throughout the oven. Thermal oil heating, such as that used in the MIWE Thermo-Rollomat, uses a system of tubes to circulate oil throughout the different oven zones. This method often is cited for its energy efficiency because manufacturers claim the oil’s heat retention capabilities keep costs down.
Cost considerations tend to run in favor of most indirect heating systems. The air or oil does the baking, so the need to continuously pump gas to the oven burners is eliminated, thereby lowering fuel costs. In addition, an indirect-heat oven has no burners, so maintenance is easier and less costly because each burner must be checked, as do the pipe burners, electrical connections and safety connections.
Hybrid ovens, arguably the best of all possible worlds, offer bakers the option to combine several sources of heat to create the optimum baking profile. Hybrid ovens are especially popular with bakers who produce multiple products on one line.
Most hybrid ovens have direct gas-fired heat in the front of the baking chamber, which provides a fast rise and seal. The back of the oven uses convection heat, which removes moisture and produces even color.
Hybrid ovens offer the options bakers today require, according to Spooner Vicars’ Douglas. “What we’re seeing are more efficient ovens with longer and wider production lines,” he says. “People are getting more capacity out of the lines they’re running. Bakers want more flexibility and the best way to achieve that is to employ more than one type of heat. The advantage to hybrid ovens, with gas fire at the front and convection at the back, is you get that high level of heat at the front, which expands and dries the product; then you get the drying and coloring from the convection end. When you put the two together it looks like the same oven.”
If floor space is limited, bakers should consider installing a vertical oven, which bakes products on rows of pans that move on a vertical plane as high as 20 ft. For bakers who want to increase production without increasing plant size, vertical ovens are a viable option.
The oven is the heart of any bakery and selecting the correct one is crucial to the success of a baking operation, large or small. Bakers should consider their needs and budget, examine the various styles, heating methods, controllers and maintenance issues before making a commitment.
The right oven for your operation may not be the least expensive, but a smart and informed choice pays for itself in the long run.