Speed and consistency are hallmarks of an efficient foodservice operation. Convection ovens help operators achieve these goals by evenly cooking food items utilizing a fan that circulates dry heat. This provides more uniform results in less time compared with a conventional oven. Cooking temperatures in these units are decreased by about 30 percent or more.
Foodservice operators employ convection ovens for a number of applications in the back of house. While baking remains the primary use, operators also use this equipment to roast, brown or rethermalize menu items. Operators can stack pans in these units and still obtain the same even heating results, as the cooking cavity remains at consistent temperatures throughout.
While 1 convection oven can take up as little as 10 square feet, these units also can be double stacked for increased productivity and space savings. Available in either gas or electric versions, foodservice operators can choose between floor or countertop units to help meet their space requirements.
Convection ovens come in three standard sizes. Models that can accommodate full-size pans have cavity dimensions that can handle 5 or more standard 18-inch by 26-inch sheet pans. Smaller half-size units, more suitable for lower volume applications, have interiors that can hold a half-size sheet pan.
A bakery depth convection oven offers an interior with a 4-inch deeper cavity. Because pans can be loaded in left-to-right or front-to-back positions, this allows for increased air flow.
Full-size convection ovens come with either single or double doors. Double-door ovens come with either independent doors that open separately, or a dependent or synchronized type, where both doors open and close simultaneously. Doors are typically fully insulated and include cool to the touch handles.
Convection ovens typically feature a fully welded frame made of either stainless or a combination of stainless and galvanized steel. While dipped in zinc to prevent rusting, galvanized steel also scratches more easily. A porcelain interior also is available with some models.
Fans provide even heating, with either high and low or a one-speed setting. Some fans automatically switch direction when the oven door is open. Because the air flow impacts how evenly food will brown in a convection oven, some units come with fans that circulate air in two different ways. Convection ovens may also combine a reversing air system with state-of-the-art controls to improve performance and offer more even and accurate baking.
Other standard convection oven features include stainless-steel door seals; double-pane thermal glass windows; two-speed fans with high and low settings; interior lights; porcelain interiors with multiposition, removable rack guides; and mechanical dial controls, including cool-down functions and continuous ring timers.
Foodservice operators can choose from a number of different options when purchasing a convection oven. Operators can include a steam injection feature, which keeps bread crust cool and provides a crispy texture. There also are models with higher horsepower and more Btus. A core can increase the thermostat’s accuracy. Other options are available, such as interior lights, preprogrammable controls with recipe storage and shelf timers.
There are a number of specifying considerations with convection ovens. Operators need to take into account how the oven will be utilized to determine which type is best. If the unit is running all day, seven days a week in a restaurant, the buyer should consider a high-end unit with more horsepower. If it’s only running an hour a day nine months out of the year, like in a school, the buyer can save money by purchasing a lower end model.
Assess the kitchen’s layout to ensure it can meet the oven’s space requirements. Operators also need to look at the service requirements of the oven to ascertain if it will require taking the whole kitchen off-line for maintenance or repairs.
When purchasing, other factors to consider are the unit’s overall durability, since this is one of the kitchen’s biggest workhorses; even air distribution or air flow; the minimization of handling pans or rotations inside the oven; and the door design, as this is what takes a great deal of abuse.
More units are available with touchscreen controls, which provide increased functionality. There also have been more efficient burner systems created that provide more power with higher Btus.
Operators should check with their local utilities to see if rebates are available when they purchase Energy Star-rated convection ovens.
FE&S: What are the main requirements for cleaning convection ovens?
TG: Maintenance for convection ovens is pretty simple. This equipment just needs to be wiped down daily with soap and warm water. Probes also should be kept clean by wiping when needed.
FE&S: How often should convection ovens be professionally serviced?
TG: For the most part, with newer units, very little calibration is needed. Once a year, operators should have the unit checked by a service technician. This will ensure the blower motor and intake fan are operating properly.
FE&S: What is the most common mistake operators make when cleaning and/or maintaining these units?
TG: The biggest problem we find is that operators will use large amounts of water to clean the oven, and this is not necessary. Spraying water from a hose can saturate wiring, interrupting operation. We’ll often get a service call for ovens that won’t turn on because too much water was used for cleaning. Fortunately, most end up working after drying out. Also, the use of chemical cleaners should be avoided, since these can damage probes that are located inside most convection ovens. For easier cleaning, most factories offer a stainless steel sheet that sits at the bottom of the cavity.
FE&S: Are there any installation considerations that can enhance the service life of a convection oven?
TG: Operators should make sure the unit has between 4 and 6 inches of space between the motor and the wall. Also, operators should be aware of where the oven controls are, although most are on the right hand side. So as not to impact the convection oven’s controls, adjacent equipment that generates a lot of heat, such as fryers, griddles or ranges, will need a separation barrier, such as a heat shield or cooling stand.
FE&S: What are the signs that a unit needs replacing?
TG: If the motor doesn’t click on right away, the unit may be failing. Also, when the operator starts the unit and the blower motor starts to spin, there is most likely a problem with the centrifugal switch, which starts the motor. This would entail replacing the entire blower motor, which has about a 10-year life span. We also sell a lot of door switches, due to door abuse with these ovens.
To ensure the convection oven meets an operation’s needs, there are a number of factors to consider prior to purchasing. Here, Dan Bendall, principal at FoodStrategy Inc., Rockville, Md., provides a consultant’s viewpoint on the category.