Ask a baker if they want their bottom boosted and chances are they’ll run a mile. Those who stick around are clearly in the market for the latest in tunnel oven kit, as was the case with one leading bakery food manufacturer, which is installing Britain’s first Mecatherm three-deck tunnel oven. While we’re not allowed to reveal the name of the baker, we can share the specs with you. The unique oven combines convection and radiant, allowing products to be baked on both the trays and the hearth. The Mecatherm FTM oven incorporates a Bottom Bake Booster (BBB) system, which consists of a controlled hot air convection bake limited to the sole of the product. The top is baked by radiant heat without any turbulence in the baking chamber.

It comes as part of a line that includes an automatic prover, vacuum depanner, a cooling system for the empty trays and a tray storage system enabling changeover of trays. Epsom-based European Process Plant, which supplies the ovens, is just about to finish the commissioning trials.

"This combination of radiant heat and controlled air convection heat results in a very high quality finished product," said EPP managing director Keith Stalker. "For example, it allows plant bakers to control crust thickness and produce sandwich breads with a thin top crust and a heavier crust at the sole. Another advantage is that products can be baked on the hearth without marking the bottom crust."

Flexible system

The modular oven is also suitable for producers of part-baked hearth products that require very short bake times. This results in high residual humidity in the products without any collapsing. It is also said to increase the product’s shelf life.

The system is very flexible, allowing rapid switching from hearth production to tray baking. The oven’s advanced, easy-to-use control system gives the baker full control over the bake with the oven’s parameters being able to be quickly changed. The non-turbulent atmosphere created by the use of radiant heat results in reduced steam consumption and excellent development of the upper crust, claims EPP.

One bakery we can name that has recently installed a tunnel oven is Manchester’s GH Sheldon. The morning goods supplier needed additional bespoke baking capacity to meet increased demand the company supplies all the major multiples and is focusing on growing the Sheldon brand throughout the UK. A brown muffin has been introduced, extending the broad range of white and brown baps, teacakes and potato cakes.

Sheldon’s signature product is the Lancashire oven bottom muffin, baked on both sides in the traditional way a unique process patented by Sheldon. With an extremely tight crumb structure and premium ingredients, it required consistent baking.

Expansion plans created the need for two additional tunnel ovens and, after a thorough search of the market, Sheldon went with Dutch baking specialist Den Boer Baking Systems, which had supplied its existing 15-year-old tunnel oven. Den Boer, now part of the Tromp group, has been making industrial tunnel ovens for more than 100 years. They can be found all over the world in wide-ranging applications, including bread bakeries, pizza plants and on pie and puff pastry lines.

"We were obviously influenced by the fact that our existing Den Boer tunnel oven had worked for so long," says managing director Lee Sheldon.

The two new gas-fired ovens run 24 hours a day, six days a week, and are installed in an additional building, which doubles Sheldon’s production capacity.

"We don’t believe that regional products such as the Lancashire oven bottom muffin are dying; in fact, they seem to be becoming accepted nationwide," says Sheldon.

While some bakers are finding success with traditional products, the increase in popularity of speciality breads with toppings has generated new challenges for bakers, particularly in terms of cleaning and safety.

Toppings such as butter and cheese can be extremely volatile. If they drop into the bottom of the oven and become trapped they can pose a serious fire risk.

The Double D Clean In Place (CIP) system was developed to address this very issue. An integral part of Double D’s Continuous Baking Oven, the CIP is a unique system of sparge pipes that deliver a pressurised, heated, caustic solution throughout the oven, thoroughly cleaning any debris or residue. This significantly reduces the fire risk and can impact considerably on insurance premiums.

"This system is vital to us as baking with toppings requires much stricter hygiene and safety standards," says Mark Jones, manufacturing director of New Primebake, part of the Bakkavör Group, which has factories in Nantwich, Barton and Crewe. The plant at Crewe uses a Double D Continuous Baking Oven to produce speciality breads for most of the UK’s major supermarkets, together with a range of hand-crafted breads with speciality toppings.

"The oven can be fully programmed and accurately timed to bake each product exactly how you want it," continues Jones. "The consistency across the belt is always excellent, as the airflow system gives complete control over both top and bottom heat and provides equal firing at the edges of the band there is never any scorching. It also contains a water bath, which collects and discards the volatile residue, while halving our cleaning down-time."

Versatile programming

The high impingement oven can be programmed to suit any number of different recipes and specifications, while the travelling stainless steel belt can be custom-built to practically any required width. Pizza, quiche, pastries, pies, savouries, morning rolls and confectionery can all be baked ­consistently at high volumes. Double D, which is now part of JBT FoodTech, has also developed a high temperature continuous oven for pizza and flat bread production, which can bake a 10-inch pizza in 1½-2 minutes at 750°F.

When you’re baking on an industrial level, you want to clamp down on the energy usage. The Hanseat range from Germany-based Daub is a multi-deck tunnel oven system that can either be batch or continuous. It offers a step-loading system that means heat cannot escape when doors are opened. Its main point of difference is its use of thermal oil.

Daub’s ovens use thermal oil to heat a radiator which runs through the oven and maintains it at the optimum temperature throughout its entire length a bit like a domestic central heating system that maintains the same heat throughout a property. Thermal oil has allowed Daub to increase the efficiency of a radiator system and minimise the heat conveyance losses external and internal to the oven. This high heat capacity means the peak radiator temperature can be lower, so losses are reduced.

Thermal oil also allows the manufacturer to look closely at its radiator design. A thermal oil radiator is not part and parcel of the oven structure it is a radiator optimised for heat transfer. It can be manufactured and optimised separately to the structure of the oven, says supplier Benier UK, which is part of the Kaak Group, Europe’s largest manufacturer of bakery equipment. Claims of up to 30% saving on energy costs, based on existing users’ experiences, are certainly worth noting as margins on high-volume products look set to get ever tighter.