At its simplest, a hybrid oven combines different types of heat transfer in one oven.
“A hybrid oven is a combination of technologies that allows for the exact point in the baking cycle to remove moisture,” said Dennis Kauffman, director of thermal systems, AMF Bakery Systems. “A hybrid oven can exactly duplicate the heat flux curve most beneficial for a specific product.”
This allows bakers to turn out consistent, evenly baked products efficiently. All it requires to optimize a hybrid oven is a little understanding about how the product bakes and the best heat transfer to achieve it.
“With pizza, for example, what they’ve learned is a direct-gas-style steel plate oven in the beginning gives a nice, firm bottom and oven jump to set the cell structure,” said Damian Morabito, president, Topos Mondial. “At the back end, air turbulence and impingement oven or convection oven is where you get the even color.”
And because hybrid ovens contain multiple forms of heat transfer, not only are they efficient, but they also are highly versatile.
“Hybrid ovens allow more flexibility for different types of products to be run on them,” said Tremaine Hartranft, director of technical services, Reading Bakery Systems (RBS). “In the long term, this allows bakeries to change quickly to market demands.”
A tailored bake
Hybrid ovens by their very nature enable operators to optimize the baking profile of their products. At different stages of a bake cycle, products develop and set different characteristics. At the beginning, yeast-raised products will gain their oven spring, and pizza crusts will set the bottom. At the end, the main goal is to finish the color. These different stages can be achieved in an oven with one heat transfer type, but hybrid ovens allow bakers to match the best heat transfer system to the goal of each zone.
“You’re able to optimize the efficiency in the throughput and bake time for that specific product by designing your oven to give the product the heat it wants to see through the stages of baking,” Mr. Morabito said.
For example, while air impingement or turbulence at the end of a baking cycle will help an artisan bread develop color, baking it in an oven that only uses air impingement heat transfer would create a crust rupture.
“It will rip because you set the crust while the dough is still expanding through the baking process,” Mr. Morabito said. “You want to let it expand from the inside and use steam to help with the outer crust structure.”
While many baked foods benefit from a hybrid oven, crackers particularly benefit from combining different forms of heat.
“The convection sections of the hybrid ovens help reduce moisture more evenly in the product, which helps minimize product breakage, or checking, in the package as the moisture equilibrates in the product,” Mr. Hartranft said.
With so many different heat transfer technologies available, bakers can customize a hybrid oven to their product portfolio, particularly to ensure flexiblity with future products. Babbco offers eight different technologies in various combinations for a customized oven.
“Babbco hybrid ovens allow the oven to be tailored exactly to the needs of the customer and product range, providing a superior baking profile that optimizes both baking time and product characteristics without sacrificing one for the other,” said Jerry Barnes, sales, applications and systems engineering, Babbco. “Sometimes this involves different methods of applying heat from the top and bottom. In other instances, the oven heating or burner technology is varied in the direction of product travel.”
When designing these ovens, Babbco engineers use the latest in 3-D modeling technology to combine a variety of heating methods in a smaller oven. The latest in fine color and steam control also helps bakers get repeatable results in their hybrid ovens.
RBS offers several different platforms that allow bakers to mix and match according to their needs. The company’s direct-gas-fired ovens feature high- and low-density burner patterns as well as the option to add infrared burners. On convection oven sections, bakers can upgrade to an Emithermic oven section, which uses either convection or radiant heat.
While not technically a hybrid oven, Mecatherm’s M-TA allows operators to choose between radiant, convection or a combination in each zone. There is a total of six combinations available in addition to steam injection.
“This allows bakers to build a tailor-made baking curve for an infinite range of products,” said Marie Laisne, oven product manager, Mecatherm.
For smaller operations not quite ready for tunnel ovens, Tagliavini, represented in the United States by Erika Record, offers the Termik Mix Deck Oven. A Tronik electric deck can be mounted on top of the gas Termik, giving bakers flexibility to bake on the top deck different products than those on the Termik.
“This allows bakers to be more precise in directing heat to the bottom if they like a heavier bottom bake or focus the heat on top for products that require darker coloration on the crust,” said Cindy Chananie, commercial business development, Erika Record.
Getting the optimal baking profile with multiple types of heat transfer also allows bakeries to run faster. With a more efficient bake comes shorter bake times and greater throughput.
“While it may have taken longer to get the right color using all direct fired, you’ll get it in less time if you go direct fired and then add the turbulence section on the end,” Mr. Morabito explained. “You’re shortening up your bake time, increasing throughput for the same size oven.”
Combining heat styles to optimally bake, however, requires understanding what a product needs as it moves through an oven.
“The individual product baking profile usually determines if a single-style or a hybrid mix of two or more styles would be most efficient for the rate and most effective for the overall quality of product needed,” Mr. Kauffman said.
Test bakes at innovation centers enable bakers to nail down the optimal baking curve.
“Through our vast experience and knowledge, we can advise customers the best solution, but we can also test the baking concepts on the hybrid oven in our Application center,” said Kevin Knott, key account manager, Franz Haas Machinery of America, Inc.
Hybrid ovens not only allow bakers to design the perfect baking curve for their products, but they also enable them to be more flexible.
“While hybrid ovens have been in use for many years on tin bread, deep dish pizza and Knäckebröd applications, we will see hybrid ovens increasingly used on applications for the production of sweet goods, snacks, pizzas and gluten-free products in the future because of the evolving uniqueness of customer product lines,” Mr. Kauffman said.
If bakeries need a flexible operation that easily adapts to new products, it’s important to think beyond the optimal baking curve for current products.
“By analyzing the products they wish to make now and in the future, bakers can work with oven suppliers to make the best fit for their operations,” Mr. Knott said.
Mr. Morabito said one such flexible combination is a cyclothermic indirect-fired oven at the beginning with convection or air impingement at the end.
“That covers a lot of products well in one oven,” he said.
Direct gas fired at the beginning with air impingement at the end also can provide bakers with ample flexibility.
The beauty of a hybrid oven is that, with controls in place, bakers essentially have three ovens in one: the full hybrid with all zones firing, or the operator can turn the front or back ends down and run just one end of the oven.
“With some of these ovens, you can diminish the effect of the second oven and run just the one type or vice versa,” Mr. Morabito explained. “You’ll have less throughput, but your product mix can be varied.”
The M-TA oven from Mecatherm features a mobile hearth system that allows operators to choose convection or radiant heat for the bottom baking chamber. This feature can be in each independent heating module, giving bakers control over where in the baking cycle this heat is applied for different products.
It’s also critical that operators can change the baking profile quickly on a hybrid oven.
“Thanks to extreme responsiveness, the oven reacts very quickly to any load variation, maintaining perfect quality all along the production,” Ms. Laisne said. “The oven benefits from an accurate air-flow control inside the baking chamber to ensure baking homogeneity even for delicate products that are thin or have sugar content.”
New technology also can expand what hybrid ovens can deliver. Middleby Bakery has taken its expertise from high-output meat smokehouses and brought it to the bakery.
“Auto-Bake is integrating this same smokehouse technology into our hybrid oven technologies, thus inspiring completely new smoke-flavored product offerings in bread, pastries, cakes and other savory bread products,” said Scott McCally, president, Auto-Bake Serpentine.
Advancements in solid-state radio frequency (RF) technology also has brought more precision in baking and cooking.
“RF cannot produce exceptional products alone,” Mr. McCally explained. “It requires most and, in some cases, all of the other thermal technologies to produce the same quality finished product. Using RF in concert with infrared, convection and steam, bakers can achieve as much as 70% less thermal processing time with as little as one-tenth of the energy.”
The optimized baking profiles delivered by hybrid ovens cut down on baking time and energy use.
“Hybrid ovens are more efficient and use less fuel when baking the same amount of product when convection sections are added to more traditional direct-gas-fired oven zones,” Mr. Hartranft said.
Technology can be added, however, to measure energy efficiency and ensure the savings are optimized.
During the design phase, RBS uses software to simulate how air will flow inside the oven. This data allows the company to create the most efficient air-flow pattern inside the oven, which, in turn, means less energy will be used for maximum baking efficiency.
Mecatherm can equip its M-TA with a continuous exhaust gas measurement device so that bakers achieve a balance between oven inlet and outlet flows to optimize energy consumption.
The Termik Mix from Erika Record features Tagliavini’s energy management system, which allows the baker to choose the percentage of power used for heat recovery.
“With the energy management system, the baker can dial in the percentage of power used for more precise baking results based on the individual product,” Ms. Chananie explained.
While 100% of amps for heat recovery may be ideal for short bakes such as pizza crust, it will be too aggressive for longer bakes such as in the case of bread.
“When you put the oven’s recovery time in the hands of the baker, they not only improve the baking quality of their products, they are also in control of their monthly electric bills,” she said.
Hybrid ovens can empower bakers to get the just-right bake they need.
“Having the hybrid oven gives you a better product, which will create more longevity for that product and greater consumer loyalty,” Mr. Morabito said.
This article is an excerpt from the October 2019 issue of Baking & Snack. To read the entire feature on ovens, click here.