Developments in hybrid tunnel ovens are giving bakers even more choice than before, but they need to be aware of the difference in costs and what suits the products they bake.
If a business is in the market for a tunnel oven, one consideration will be whether to opt for a hybrid model.
Tunnel ovens typically use a single method of heating, such as convection or cyclothermic, while a hybrid oven will use a combination of two or more types of heat, enabling greater control at the various stages of baking.
A baker should choose what’s best suited to their business and the type of products they bake, suggests Spooner Industries sales manager Michael Lomas, as the difference between the cost of a hybrid and one using a single heating medium can be minimal.
Any savings in one area can be eaten up elsewhere, he adds: “What you might save in oven body construction for a hybrid oven you would spend on the increased number of burner and gas train components.”
There can, however, be differences when it comes to running costs. Running a hybrid is generally more expensive than a 100% convection oven, says Lomas, but can be less costly than some other types of oven, such as a 100% radiant one.
Bakery equipment manufacturer Mecatherm says its data shows its FTA modular oven uses 15% less energy for the same amount of output compared with a traditional cyclothermic tunnel oven.
Launched two years ago, the FTA allows bakers to choose between convection and radiant heat in both the top and bottom of the oven, while they can opt for radiant or convection heat in the bottom of the oven. “There are six possible baking combinations from a single piece of equipment,” says Steve Merritt, managing director of Epsom-based equipment supplier EPP.
“This level of control means that, because you can bake in all types of trays and tins and also directly on the hearth, it is suitable for virtually every type of bakery product, from crusty and soft breads and rolls to sweet and savoury pastries and even crème caramel.”
Unlike conventional ovens, where the air of the baking chamber is moved by a fan, convection energy transfer in the FTA is a vertical high-speed air jet sent directly from the heat generator.
Over recent years, EPP has diversified into offering tunnel ovens with dough capacities of up to four tonnes an hour for making products including ciabatta, tin bread, buns, rolls, pastries, pies and pizza.
In one UK bakery EPP has installed a unique three-deck tunnel oven that combines convection and radiant heat, allowing products to be baked on trays and directly on the oven sole. This operates as part of a line that includes an automatic proofer, vacuum depanner, cooling system and a tray storage system enabling an automatic change-over of trays.
The Mecatherm FTP II has advanced the process of baking on a stone-hearth in a single-deck tunnel oven. Heated by a dedicated system, the stones can reach up to 230˚C without overheating the baking chamber, enabling bread and crumb development to occur under optimum conditions, says the supplier.
Other technological advances driving hybrid development have included pipe burner and gas train equipment that enables burners to run more efficiently and reliably for longer. Meanwhile, the development of pure radiant pipe burners has negated the need to use the oven walls in the heat transfer process.
Spooner’s automated feedback systems use vision sensors to control the oven, based on the quality of the product baked. “The ‘feedforward’ system looks at production upstream of the oven to accurately anticipate gaps in production, making sure the oven is not wasting energy when there is no product, but is ready to bake when it starts again with minimal flash heat effect,” says Lomas.
Koenig’s SDD EOS oven can be supplied, installed and maintained by EPP
Koenig enters tunnel sector
Although better known as a manufacturer of automatic roll plant, Koenig has continued to diversify and has recently entered the tunnel oven market.
The Koenig SDD EOS, supplied, installed and maintained by EPP, is a direct-fired tunnel oven, offering baking temperatures from 150˚C to 500˚C.
It uses ceramic burners to bake primarily with infrared heat and is described as ideal for products that need a high temperature and a short bake, such as pitta, naan, pizza and focaccia. However, as the temperature can be widely modulated down to 150˚C, virtually any type of rustic product can be baked in it, says EPP.
Available in five standard conveyor widths – 900, 1100, 1300, 1500 and 1700mm – the SDD EOS offers a baking surface of up to 60sq m. The baking chamber can be divided into up to four zones with dedicated burners allowing independent temperatures to be set and independent control of the top and bottom of each zone.
According to Koenig, highly efficient insulation ensures heat loss is kept to a minimum and stone-plate and wire-mesh conveyors are available. Koenig also offers options such as install steam at the infeed and turbulences inside the baking chamber if required.
Late last year, Koenig announced it had set up subsidiary Koenig Technology Project to design and install turnkey projects for bakeries. The company has expanded its portfolio and will be involved with mixing and transporting, dough processing, and baking and cooling.
The services of the new operation will be available through EPP, which has worked with Koenig for a number of years, supplying and installing machinery to British craft and in-store bakers.