It may be that combi ovens are not yet a kitchen mainstay but they are starting to come close. Today their popularity has grown so much that they are commonplace in many types of operations. The units are so useful and versatile that if you ask chefs to name the most productive pieces of equipment in their kitchens, invariably the combination oven/steamer is singled out at the top of most lists.
Many will say the combi is the heart of their hot food production lines. Others vouch for the units being responsible for finishing more items on the menu than any other piece of equipment.
The really great thing about a combi is that many menu items can be wonderfully baked, roasted, and steamed in one unit. Products that all too often tend to dry out during conventional cooking come out tender and moist in a combi. It's no wonder chefs like combis so much — versatility is the name of the game in today's kitchen.
Essentially an oven/steamer can do everything that a steamer or a convection oven can do and in many cases better than either. They can run in any of the three operating modes: steam, convection, or steam and convection.
Some models offer additional specialty modes using hot air and steam to defrost, rethermalize, poach or gentle steam, and warm. Many types of red meats and poultry products are well adapted to combination cooking because they can be prepared so many ways.
Steaming of vegetables and fish, of course, is easily done. Some users say their best baked pastries and rolls come from their unit. The steamer/oven operating in the combination mode provides forced air convection for even browning along with steam for moist heat, a very effective technique for preparing many types of food.
The combination mode is especially well suited for producing less shrinkage in meats than typical ovens. Breads and rolls baked in the combi mode will be fluffier and have more oven spring than those baked in traditional ovens. Rethermalizing leftovers and heating prepackaged frozen convenience foods also works well in the combi mode to reduce drying and over-browning.
There are other reasons to use the equipment. The combination oven/steamer can save space. Space is the ultimate premium in many operations these days. As we all know today's kitchens are shrinking because we can't afford the luxury of space found in many older kitchens. The combi takes up about half the area of a convection oven and steamer that may free up space for other items or just some badly needed work space. The space saved can translate in to cost savings as well.
Using less exhaust hood stainless steel and the ongoing cost of exhausted air-conditioned air over only three or four feet of reduced length can represent a significant ongoing energy cost. The hood cost along with the savings due to reducing or consolidating pieces of equipment can be significant, but the typical combi is still expensive.
There is a new type of combi that promises to make owners happier about the cost of these units. Several manufacturers have engineered a lower cost line of combi ovens that will appeal to the operation on a budget. The newer type of combi is a boilerless unit. The expensive boiler is eliminated and the resulting steamer/ovens cost about 15-20% less. The only drawback is slightly reduced steam output needed in high volume fast cooking. In many applications the difference in the units is not noticeable. These new boilerless units have opened up an additional market for combi ovens to make them available to even more operations. There is an added benefit to the boilerless combi: reduced liming problems due to hard water. Over half of combi maintenance problems are due to excessive scale and lime build up which can be eliminated in a boilerless model.
The oven/steamers on today's market range from small volume countertop units to floor-mounted roll-in units with large capacities for banquets or institutional use. Typical sizes are stated by manufacturers in standard steam table pan (12"×20") or baking sheet pan (18"×26") capacities.
Note that shallow 2 ½" pans are typically used in the sizing ratings. You will need to reduce capacity accordingly if using 4" or 6" 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" × 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"×20" pan or half size baking pan. The larger units hold two 12"×20" pans on each shelf or a single 18"×26" baking pan.
A primary consideration is whether the combi will be gas or electric. All sizes and styles are generally available as electric units. Gas units are produced by some manufacturers, but are usually more expensive and only available only in certain size models. If you are using an electric unit, be sure to have enough power as they generally require a fairly substantial load. For example, a ten steam table pan unit requires between 13 and 19 kilowatts to operate.
As with all steam equipment, the quality of water going into the combi is of utmost importance for good equipment performance. The majority of all service problems with combis are related to liming or mineral deposit build-up. Most manufacturers definitely recommend a water filter for the equipment. Have your tap water tested for hardness and use filters to correct the level to within recommended standards, but don't stop there.
You should 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 when deliming is necessary. When activated, the combi then goes into a deliming cycle using chemicals supplied from a special reservoir on the unit.
When selecting equipment, you should also be aware of and perhaps choose from among additional options such as programmability. Look carefully and buy the options you need, but don't over-buy. A step up in features can easily add several thousand dollars to even a small counter-top model.
Among those options you should consider: Most units are generally easy to clean, but some 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, used when the oven/steamer is next to other cooking appliances to prevent the item's electrical controls from getting overheated. Solid state and computerized controls are very sensitive to heat and can easily be damaged if they are in the close vicinity of a range or broiler.
There are other more subtle advancements in combis being made by several manufacturers. These include enhanced fan designs, for more even air movement, and better self-cleaning options.
Dan Bendall is a principal of FoodStrategy, a Maryland-based consulting firm that specializes in planning foodservice facilities. A member of Foodservice Consultants Society International (FCSI), Bendall can be reached at 240-314-0660.