Gas combination ovens are designed to create and deliver two of the most popular forms of commercial cooking heat transfer – pressureless (atmospheric) steam and forced convection hot air. These two primary cooking methods may be used separately or simultaneously. This means the combination oven gives you a choice of three basic cooking modes of operation.

This “triple threat” cooking capability has many advantages. First, since a gas combination oven may be able to do the work of two or more other types of equipment, you can save on the initial cost of kitchen equipment. Less equipment to buy can reduce ventilation hood space requirements and its cost. A single piece of equipment doing a multitude of cooking tasks can improve the efficiency of your entire production and service system while also saving labor cost.

Multimode cooking also translates into an almost limitless array of food preparation possibilities. Some of those possibilities include: baking, roasting, oven braising, poaching, steaming, rethermalizing, wet roasting, crust baking, proofing, thawing and warming. Multimode capabilities enable you to prepare an extensive variety of America’s favorite foods. Bagels, breads, pies, cakes, steaks, hamburgers, meat loaf, pizza, hot dogs, roasts, cutlets, chicken, fish, shellfish, vegetables, eggs and casseroles are some of the possibilities. The combination mode (steam and convection hot air) can increase many meat product yields due to more moisture retention and less shrinkage. This mode is also ideal for some baked goods that require a browned crust and a fluffy or tender interior.

It is this combination of benefits – multimodes of operation, variety and quality of foods, cost saving potential and extensive end user applications – that account for the success enjoyed by gas combination ovens since the first gas combination oven made its United States debut in 1989. Since then customer demand and satisfaction has spawned extensive research/development and marketing activity by several manufacturers. Today, only about a decade later, you can select from over 40 models with an array of options.

Half-size models feature cavity interiors that will accommodate six to ten 18" x l3" x l" half-size bake pans or four to ten standard 12" x 20" x 2-1/2" steam pans. These smaller models are frequently installed in lower volume operations or in kitchens where space is extremely limited. Although half-size models provide less production, they deliver the same cooking performance and multimode functions as larger models.

Full-size gas combination ovens provide additional production capabilities. Models are available that will handle up to 24 steam pans or 12 full-size 18" x 26" x 1" baking pans.

Both half-size and full-size ovens may be stacked two cavities high which can double the production potential without taking up additional linear kitchen space. Double stacking also provides additional preparation and production flexibility. For example, one cavity may be steaming vegetables while the other cavity is in the combination steam/hot air mode preparing meat or baked goods.

In some full-size models there is another stacking option. Some models can be stacked with a full-size convection oven. If you do not require double combination oven production, the purchase of a combination oven and a convection oven will save on initial purchase cost and still reduce kitchen equipment space requirements.

Gas roll-in combination ovens offer the largest pan capacities per cavity. Depending upon roll-in model, single cavities will handle up to 46 steam pans or 23 full-size bake pans. These large ovens are used in very high production facilities, frequently in conjunction with cook/chill systems. In cook/chill operations, oven compatible transportation carts containing foods that are fully or partially pre-cooked are removed from a refrigerated storage area and wheeled directly into the roll-in combination oven’s cavity. You then select the appropriate cooking mode, the time, temperature, program, etc. and remove the cart when the cooking cycle is completed.

The oven’s cooking chamber is accessed through an oven door (single or duplex) that is either full stainless steel or a combination of a tempered glass viewing window and stainless steel. Lighted cavity interiors and field reversible doors are another couple of options.

Full and half-size models can normally be mounted on a noncombustible counter or equipment stand. The stand may be equipped with rack guides to hold pans and save labor time and steps. The equipment stand may have stationary legs or be equipped with casters to provide mobility for cleaning.

Gas burner systems and methods of producing and delivering pressureless steam and convection hot air vary according to brand and oven model. All models employ a power fan (blower) system which enhances heat transfer efficiency and cooking speed. Most fans are located in the cavity while others are located above the cavity. Some power fans offer multispeed functions and others have a reverse fan heat recycle system.

The pressureless steam portion of the combination oven equation can be supplied either by a gas-fired steam generator integrated into the cabinet design, a water injection “spray” system that does not require a steam generator, or from a remote steam generator or boiler. Each of these methods of introducing steam can offer their own set of advantages depending on your individual requirements.

The convection hot air is furnished by various types of energy efficient gas burners. These hot air systems feature burners that can supply heated air directly into the cavity or indirectly through a heat exchanger. Gas combination ovens have burners with maximum connected loads (steam and convection hot air) ranging from 45,000 to 225,000 BTUs. Half-size models generally have the lowest BTU ratings per cavity while the largest roll-in equipment requires the highest energy input.

Precise cooking cavity temperature control and regulation of the pressureless steam and convection hot air functions are trademarks of gas combination ovens. Oven control systems vary by brand and model. Some of the control system features to consider are: cook and hold, digital time and temperature readouts that allow you to set and monitor both time and temperature, Fahrenheit and Celsius readouts, audible product alarms, the temperature range of the oven’s thermostatic control system, icon and numerical touch pad control activation, programmable controls that offer up to 99 programs, and product temperature probes that enable you to monitor the food product’s internal cooking temperature.

There are a number of other options to consider such as a humidity control system, hoses with spray nozzles to reduce cleanup time, integrated proofing cabinets, self-diagnostic service systems that reduce service time, and on models with integrated steam generators – steam ready modes for instant steam and automatic self-flushing (blow down) capabilities that reduce the need to delime (clean) and thus extend the generator’s life. Easy-clean deliming ports are another asset.

Since gas combination ovens are still a relatively new concept, especially the combination pressureless steam/convection hot air mode, a “test drive” with some of your own products is the best way to evaluate the world of possibilities. Manufacturers, their sales representatives and some gas utilities can set up a cooking demonstration. Manufacturers can also provide marketing videos and are available to discuss and demonstrate gas combination ovens at industry trade shows.