For cook lines with limited space, combi ovens take the place of multiple pieces of equipment, including convection ovens and steamers. These units also can replace cook and hold cabinets, proofers or slow cookers when used at low-heat settings.
Combi ovens are suitable for use across all types of foodservice operations’ cook lines, from white tablecloth restaurants to schools. Operators can use combi ovens to perform a variety of tasks, including roasting, steaming, sous vide, smoke, braise, bake, retherm and oven fry. These ovens balance humidity, convection oven capabilities and steam by combining hot air with heated steam. Because the air moves around the food item being cooked, and combis can introduce moisture, operators have the ability to control foods’ moisture levels and increase product yield. On the line, this cooking process helps maintain the flavor and nutrients of foods, while hot air and added moisture speed up the cooking process.
Operators can choose from three sizes of combi ovens. Tabletop units have 6 to 11 shelves for half-size sheet pans and full-size hotel pans. Mini ovens have six shelves and can accommodate three to five pans. Floor models, the most common in cook lines, have 20 shelves for holding 20 sheet pans or 40 hotel pans.
In terms of power, gas combis have Btus ranging from 45,500 to more than 170,000, while most electric units are 208V or 240V.
Automatic electronic cooking controls include a humidity feature with digital instructions in multiple languages. Optional programmable controls have memory capabilities for more than 200 cooking cycles with various cooking steps.
For cooklines that prepare large amounts of proteins, combis with grease management options might be a good fit. These ovens pump excess grease out of the unit into a standalone canister for recycling.
Innovative features include ventless hood systems that allow electric combis to be placed virtually anywhere; browning controls to add color to food; and smoking capabilities that use real wood chips. Models with UPC code scanner capabilities utilize preloaded cooking instructions to set oven controls automatically. Other units offer HACCP documentation with and without the use of kitchen management software.
Size represents a key consideration when choosing a combi for a cook line.
“Combi ovens range in size from compact all the way up to large roll-in models,” says Edward Arons, senior associate, Colburn & Guyette Foodservice Designers, Rockland, Mass. “Although a larger oven means a higher capacity, it also means it might not fit in your kitchen. When you have a model in mind, the first task is to check if it will fit into the desired space before purchasing. Keep required clearances between adjacent equipment in mind, as well.”
Operators also need to assess the available power supply to determine if a gas or electric combi will work best in a given environment. “Gas could be either natural or propane,” says Arons. “Electric can be single or three phase, and voltages can differ. It’s very important to verify you have the electrical capacity in your cook line to support the new combi oven.” Although there isn’t a performance difference between gas and electric models, it’s important to note that gas ovens usually require an electrical connection for controls.
Manufacturers offer a wide range of controls, and digital or manual programmability can vary in complexity. “This is very particular to the chef or operation, menu and staff skill level,” says Arons. “Generally, manual models have buttons and dials whereas modern programmable ovens have tablet-style touchscreen panels. Chefs may prefer the hands-on manual control. However, programmable versions make it much easier for chefs to program menu items for inexperienced staff and produce good consistent results.”
Combi ovens create steam and typically require an exhaust hood by code. Check local codes to confirm requirements prior to purchasing. “Some areas allow common exhaust ducting, others may require fire rated grease ducting, which is more involved and costlier,” says Arons. “Some manufacturers have newer electric-only ventless technology that allows the combi oven to be installed without an exhaust system and still meet code requirements.”
Traditional combi ovens create steam by a built-in water boiler system, but newer boilerless units have fewer parts and tend to require less maintenance and service over time. “There are some operational differences between the two, so it is recommended that you do their research prior to purchase to decide which type is best suited for the operation,” says Arons.
One important combi oven accessory that is frequently omitted or specified incorrectly is the water filter. “You must have a water filter installed for the incoming water supply; failure to do so will greatly shorten the lifespan of the oven and cause many unnecessary service calls,” says Arons. “A one spec system for all is not the best approach. Testing your operation’s water quality is the first step to determine the correct filter system. Most municipalities provide regional water reports for free. This is better than nothing; however, it will not be as accurate as measuring the quality at your specific location. Most manufacturers will void the warranty if your water quality does not meet the minimum quality requirements.”
Many units feature programmable cooking cycles, settings for quick defrost, rethermalizing, poaching, gentle steaming, warming and smoking, among many others available. Some also offer a self-cleaning option. “Many include a side mounted hose and sprayer for easier cleaning,” says Arons. “It’s important to review the options and decide what is necessary for you and consider the cost. One thing to note on cleaning, make sure the chemicals are recommended by the manufacturer. Failure to do so can cause issues with the oven operation.”
Care & Cleaning
The largest concern in caring for combi ovens is the same as for steamers, which is water quality and scale removal.
“Water filters should be replaced every three to six months, and generators should be descaled every six to 12 months, depending on hours of use,” says Don Thompson, service technician at Baltimore-based EMR.
The average lifespan of a combi oven is 10 to 15 years, depending on conditions in kitchen. Placement in the kitchen also is a factor in these units’ service life. “If a unit is located over a drain, then steam and water can deteriorate the frame or internal components,” says Thompson. “If it sits beside an open burner range, then sides may be exposed to excessive heat, which could damage internal components.”
As a general rule, most operating components can be replaced or rebuilt, although the cost of some electronic parts has been increasing greatly in recent years, resulting in higher repair costs, he says. “If structural issues or repair costs are 50 percent the cost of replacement, a new unit most likely is required,” says Thompson.