Auto-Bake’s continuous solution is its Serpentine tunnel oven, which has the unique advantage of having one-tenth the footprint of an equivalent tunnel oven. “The Auto-Bake line is as versatile as any other line would be,” Diver says. Bakers can use Auto-Bake’s standard “contained pan” model or its “free pan” transport interface, which allows bakers to use their own standard pans–whether they’re cake pans, loaf pans or cupcake pans.

As Diver points out, "One of the benefits of using the captured pan with the Auto-Bake oven, is I can [produce consistent product at] very high speeds and I don’t have the issue of pans being separated from the system; meaning I don’t have accumulation issues and I don’t have pan damage issues, when the pan is now part of the system. I’m really set for high-speed cake production."

Oven technology

In an article entitled “A comparison of deck oven designs,” by Stephan Wechsler, president, Empire Bakery Equipment, Hicksville, N.Y., Wechsler states that the major differences between the five gas/oil-fired stone hearth deck ovens he describes are how heat is distributed and the type of construction materials used.

In the cyclothermic oven, hot gases move between and around decks through a heat exchanger or a burner. A powerful fan circulates air. These ovens are typically constructed with steel and a mineral wool-type insulation, Walker says. Some cyclothermic ovens can regulate one temperature on the top one or two decks and another on the bottom decks, which can accommodate a varied product mix.

“These ovens aren’t usually recommended for baking heavy products. As with a hot air heating system in a home, when the burner shuts off, there is a tendency for the oven to cool down rapidly until the thermostat calls for more heat. Then when the burner reignites or goes back to high flame, the temperature will rise again quickly. This produces more temperature fluctuation than might be desired for baking larger breads with longer bake times, especially if you are using steam and desire a good crust,” Wechsler explains.

Because cyclothermic ovens can cause more water to be baked out of free-standing products than thermal oil ovens, it is more suitable for pan breads, Squire says.

Wechsler also discusses vapor tube ovens including all steel “ring tube” models; steel and cement construction and cement lined vapor tube ovens “for the ultimate in brick oven baking”; and thermal oil ovens.

In vapor tube ovens, for instance, no moving parts or fans are used to distribute the heat. Thus, baking consistency is achieved from deck to deck and side to side. Yet, differences exist among the three models because of the construction materials used. All-steel construction vapor tube deck ovens, which circulate steam through a series of tubes that surround the oven and run between decks, were installed in the United States for many years. “As demand for hearth breads has increased, however, many bakeries find that an all-steel oven has less ability to maintain the best heat necessary for high production baking and steaming. This can result in a greater change in baking properties or unevenness of baking after six hours or so of heavy production,” Wechsler says.

Vapor tube ovens made steel, cement and brick, commonly used in European bakeries, “offer the best balance between heat retention, efficiency and flexibility of temperature, Wechsler adds. “These ovens utilize brick and cement in the fire chamber, which acts as a ‘heat sink.’ …When the oven is loaded with bread and steam is introduced in the chamber, absorbing the chamber’s available heat, the brick and cement supply a continuous, smooth flow of heat without the burner having to try and play ‘catch up.’”

Bakers have much to consider when striving for baking consistency. When it’s time to purchase a new oven for your bakery, bakers should work closely with their supplier to ensure they achieve their goal in producing high-quality, consistent products from the beginning to the end of each production run.

Heat versus temperature

To a certain extent, product is baked with temperature from the surrounding air, which heats up the pan, says Geri Walker, president, Bake-Tech, Tucker, Ga. To another extent, product is baked with a flame from the burner. The tip of the flame is about 1500° F. Air in the oven is about 400 F to 500° F. Therefore, a lot more heat value comes out of the burners. Separate heat zones within the oven are dependent on what the burners are doing– if the burners are full flame, low fire or in some cases, if they’re off. Most of the baking process depends on heat generated from the burner, not the air temperature. For all ovens, temperature can be read, but not the heat, Walker adds.

“In continuous ovens, we have a method of measuring heat. Our method is to put burners on under the pan, heat the pan up and whatever’s leftover we’re measuring as temperature. But the pan soaks up a lot of heat. We don’t see that part. We’re only measuring what the air took on. We have to use temperature to tell us when we’ve got too much heat and when to throttle back the burners. For example, [when there’s a production gap], the thermocouple will detect a rise in temperature indicating [an absence of product] soaking up the heat, so then you’ll throttle back the burners. The use of temperature to control the oven is valid, it’s just not the whole picture.”