What's not to like about a piece of equipment that does the work of two traditional cooking items? Combining convection oven and steamer capabilities into a single cooking cavity has been one of the great foodservice innovations. If you don't have one yet, here are some items to consider before you buy.
The combi oven offers three modes of cooking in one oven — steam, circulated hot air or a combination of both. The combination mode is used to reheat foods and to roast or bake. The steam mode is well suited for rapid cooking of vegetables and shellfish. The hot air mode operates as a regular convection oven for baking cookies, cakes and pastries. The combi mode decreases overall cook times, reduces product shrinkage and eliminates flavor transfer when multiple items are cooked simultaneously.
Some models offer additional specialty modes using hot air and steam to defrost, poach, gently steam and warm. The combi oven, operating in combination mode, mixes forced-air convection for even browning while steam produces moist heat to reduce product drying. Meats cooked in the combi mode shrink less than if they were cooked in a typical oven. Breads and rolls baked in the combi mode will be fluffier than those baked in traditional ovens. Thawing leftovers and heating prepackaged frozen foods also works well in the combi mode to reduce drying and overbrowning.
There are still other reasons to use the equipment. From a kitchen layout and space point of view, the really great thing about a combi is that it can replace two pieces of equipment in the space of one. The space saved can translate into cost savings as well. Because you're using one piece of equipment and not two, you'll also use less exhaust hood stainless steel, which also leads a significant ongoing energy savings.
Under any circumstance, a typical combi is still expensive. However, there is a relatively newer type of combi that promises to make owners happier about the cost of these units. A number of manufacturers have engineered a lower cost line of combi ovens that will appeal to the budget conscious. This type of combi is a boilerless unit. The expensive boiler is eliminated and the resulting steamer/ovens are about 15-20 percent less costly than a similar-sized counterpart. The only drawback is slightly reduced steam output needed in high-volume fast cooking. With many applications the difference in these units is not noticeable. Plus, the boilerless combi experiences fewer liming problems due to hard water. Over half of a combi's maintenance problems are due to excessive scale and lime buildup, which is 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 steamtable pan (12" × 20") or baking sheet pan (18" × 26") capacities. Note that shallow 2½" pans are typically used in the sizing ratings. You will need to reduce capacity accordingly if using 4" or 6" pans that are typical for casseroles and 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 10-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.
Once you determine the necessary size unit for your operation, a primary consideration is whether the combi will operate with gas or electric. All sizes and styles are generally available as electric units. Gas units are usually more expensive than electric units and sometimes available only in certain sized models. Generally, the smaller units are only available for electric operation. If you're using an electric unit be sure to have enough power because they require a fairly substantial load. For example, a 10-steam table-pan unit requires between 13 and 19 kilowatts.
When selecting equipment, you also need to be aware of various options. Several manufacturers have multiple lines of combis from basic to deluxe with varying amounts of programmability and other options. Look carefully and buy the options you need, but don't over buy. Steps up in features generally cost several thousands of dollars even in the small countertop models.
Most units are fully stainless steel inside and out with a glass window. They are generally easy to clean. Several models even have a built-in spray hose for washing the interior. Be sure to take special care to maintain these sophisticated pieces of equipment. As with all equipment that uses water, a filter system is needed. Filters will slow mineral deposit buildup in the unit's water lines and water contact areas. A filter also will reduce the buildup of scale on a combi oven's heating units, water probes and cooking chamber, reducing the amount of time cleaning the unit.
New features are being developed each year. One of the newest is the programming of recipes. Newer fully featured combis have touchpad picture programming. This feature allows you to add product pictures to the touchpad screen. A cook will only need to find the picture of what he or she is cooking and the combi will take it from there. Another oven option scans barcodes and prepares products for those codes you have saved. For example, the combi's scanner will recognize a barcode from a boxed frozen convenience item and start the corresponding recipe program. No need to think about any settings — just put the product in a pan and in the combi.
One manufacturer has taken fast combi cooking to the next level and come up with a useful innovation for some applications. The innovation is the addition of microwave cooking energy, which speeds the cooking process even more. This manufacturer produces a special oven with the three combi modes, including a microwave-assisted cooking cycle.
Other subtle advancements in combis are being made by several of the main manufacturers. One improvement is enhanced fan design for more even air movement. Another is better self-cleaning options for those who want to pay for this labor-saving feature.
Maybe the best thing about the combi is that unlike most innovative equipment, it appeals to every segment of the industry. The combi is an item loved by all, from casual restaurant operators to hospital dieticians. It can bake, steam or thaw a variety of menu items. Fine dining and hotel chefs embrace the precision cooking and speed. This crossover appeal has spurred on innovative new features and should continue to do so as even more kitchens embrace the combi oven.
Dan Bendall is a principal of FoodStrategy, a Maryland-based consulting firm specializing in planning foodservice facilities. He can be reached at dbendall@foodstrategy.com.