Whether you call them "combi-ovens" or " combisteamers," this one piece of equipment earns its reputation as a space saver and a real production work horse. The combi-oven derives its name from what it does— "combines" the characteristics of an oven and a steamer. It can combine oven roasting and steaming in one cooking cavity or do either independently.
Yield and quality management
The combi-oven uses dry heat— either still or fan-driven—and steam, which is injected into the oven as needed. This multi-function feature of the combi-oven means many different foods and cooking methods may be put through the combi oven. During any typical day, ribs and chickens may be roasted, fish steamed, leftovers reheated and bakery goods finished off.
The combi is an excellent equipment choice for roasting meat. Every operator is concerned with "yield" when roasting meats. The yield is the percentage of the meat's weight that is usable after cooking compared to its raw weight. Typically, from one-fourth to one-third of the weight of a piece of meat can be lost during dry roasting through the loss of a meat's water content. Using the gentle steam mode in the oven during roasting both minimizes weight loss and produces a tender piece of meat.
Fish is often a difficult product to cook well. Baking can dry tender fillets. Using the steamer mode on your combi is an ideal cooking method for very delicate products. Firmer fish steaks like tuna or swordfish can do well with a combination of oven heat and steam.
Cooking vegetables with steam instead of boiled water helps them retain more of their nutritional value and natural color. Another nice feature of the combi is that you can cook your vegetables following the fish and, in most cases, there is no flavor transfer.
Baked goods are evenly and crisply cooked by operating the combi as a fan-driven convection oven. These units can do everything a traditional convection oven or deck oven can do. A slight injection of steam can also enhance some baked foods such as bread.
If your operation does any rethermalizing of products, the combi is the perfect piece of equipment. Food that has been pre-cooked and properly chilled prior to service can be rapidly brought up to serving temperature in a combi-oven. The speed and style of cooking avoids the need to hold food hot for long periods, which causes flavor loss and drying out. Combi-ovens are ideal for busy banqueting operations and can handle both ready-plated meals and bulk containers like 12 x 20 pans.
A size for every need
Combi-ovens come in a range of sizes. Most manufacturers build ovens for small restaurants as well as high-volume outlets. The combis on the market range from countertop units to floor-mounted rollin units with large capacities for banquets or institutional use.
Typical sizes are stated by manufacturers according to standard steamtable pans (12 x 20) or baking sheet pan (18 x 26) capacities. Note that shallow 2 1/2-inch pans are typically used in the sizing ratings. You will need to reduce capacity accordingly if using 4-inch or 6-inch pans that would be most typical for casserole items or lasagna.
Most manufacturers make several of the more popular oven sizes used in restaurants. The models most available are the four to six 12 x 20-pan capacity countertop unit, a seven to ten pan unit, and the larger floor or stand-mounted 14-, 18-, and 20-pan models. The smaller units generally hold only a 12 x 20 pan or half-size baking pan. The larger units hold two 12 x 20 pans on each shelf or a single 18 x 26 baking pan.
One manufacturer makes a specialized rotisserie combi great for displaying and cooking rotisserie style chicken or other products. The unit can also be converted to traditional shelves for cooking other products.
Once the necessary size unit for your operation is determined, a primary consideration is whether you use gas or electric. All sizes and styles are generally available as electric units. Some manufacturers produce gas units. However, they are usually more expensive than electric units and available only in certain sized models. Generally, the smaller units are only available for electric operation. If you are using an electric unit be sure to have enough power because they generally require a fairly substantial load. For example, a 10 steam table pan unit requires between 13 and 19 kilowatts of electricity to operate.
As with all steaming equipment, the quality of water going into the combi is vital. Many service problems with combis are related to liming or mineral deposit buildup. Most manufacturers recommend a water filter for the equipment. Have your tap water tested for hardness and use filters to correct the level to within recommended manufacturer standards. But don't be complacent just because you have a water filter. Also have a regular program for manual or automatic de-liming. Some of the full-featured ovens have an automatic deliming program that automatically alerts the operator to delime. When activated, the combi then goes into a deliming cycle using chemicals supplied to a special reservoir on the unit.
When selecting equipment be aware of several options. Most manufacturers have multiple lines of combis—from basic to deluxe—with varying amounts of programmability and other options. Buy the options you need, but don't over-buy as steps up in features are generally several thousands of dollars for even the small counter-top models. The newer boilerless combis are generally made for the budget conscious and have fewer frills than some ovens.
Most units are fully stainless steel inside and out with a glass window. They are generally easy to clean, although several models have a built in spray hose for washing out the interior that helps in the cleaning process. Meat probes are not always standard and should be purchased, especially if a lot of meat roasting is planned. The probes are integrated into the computerized controls to provide consistent product every time you use the unit.
One important, but often overlooked operational consideration, is a side shield required on some units. The side shield is used when the oven/steamer is next to other cooking appliances to prevent the item's electrical controls from getting overheated. The solid state and computerized controls are very sensitive to heat and can easily be damaged if near a range or broiler.
About the only combi-oven drawback is its large expense. View the combi as a space saver, replacing both an oven and a steamer. When justifying the cost, compare it to that of the two items it replaces. If you can justify the cost, most agree the combi-oven is a "must-have" addition to the cooking line.
Dan Bendall is a principal of FoodStrategy, a Maryland-based consulting firm specializing in planning foodservice facilities. He is also a member of Foodservice Consultants Society International. He can be reached at 240-314-0660.