Published on Sunday, 30 June 2013
Written by The Editors
Combi ovens can save kitchen space by providing the abilities of two types of equipment in one. Many people think only about an item's kitchen footprint, but because these units combine the features and functionality of two pieces of equipment into one they can help reduce costly hood space.
Combi ovens balance humidity, convection oven capabilities and steam by combining hot air with heated steam. These units move air around all sides of the product being cooked and give foodservice operators the ability to control moisture levels. Unlike convection ovens, these units can introduce moisture, which not only balances humidity in the cooking cavity, but also increases product yield.
Most premium combi ovens feature insulation that's thicker than what's found in the typical convection oven and shut the heating element off once they reach temperature. This provides heat only on demand versus a convection oven, which provides continual heat.
These ovens help maintain the flavor and nutrients of foods, while hot air and added moisture speed the cooking process. Combis also can replace cook-and-hold cabinets, proofers or slow cookers when used at low-heat settings.
Combi capacities range from a 2/3-sized steam pan to 6 1/2-sheet pans to 40 full-size steam pans or 20 sheet pans. Operators with limited space can specify a countertop unit.
While all models feature stainless steel construction, foodservice operators can choose from gas or electric units. Gas combis have Btu ranging from 45,500 to more than 170,000, while most electric units are 208 volts or 240 volts. Gas and electric combi ovens are both available with traditional boilers and as boiler-free units.
Combi ovens also feature a variety of control panels, ranging from basic to sophisticated. The more advanced systems can cook overnight and hold food at proper temperatures until serving.
Some units utilize a heat exchanger onto which water is sprayed to create steam in the cabinet. Another traditional method uses a steam generator or enclosed box to boil water and produce steam, which the unit then pipes into the cooking cavity at a consistent and continuous rate.
Other boilerless combi ovens reclaim the heat the unit generates and uses that to help bring the water up to temperature by running it through a tube system. Because the water is preheated prior to its being injected into the system, the unit will have faster recovery times, which translates into energy savings.
Steam protection systems expel steam from the oven compartment before cooking time expires to help protect the operator from burns.
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.
- Most any foodservice operations, ranging from white tablecloth restaurants to schools, can use a combi oven.
- In addition to cooking, roasting and steaming, operators can use combis for sous vide cooking, confit preparation, smoking, braising, dehydration, baking, retherming and oven frying.
- These units are suitable for delicate functions, such as poaching eggs or even making cheese. Some foodservice operators use their combi ovens to provide flavor infusions in many different types of foods.
Combis typically have a service life of approximately 8
to 15 years, with proper maintenance. When purchasing a new unit, foodservice operators should consider a number
- Look at the operation's volume before determining the size and type of combi oven. If applicable, factor in catering needs.
- Assess the operation's budget versus the unit's lifecycle cost to determine the capital outlay over the life of the combi oven.
- Determine how culinary staff will use the oven to ensure the unit has the correct features and options.
- Compare the water and gas/electricity consumption of different units to ensure optimum energy efficiency.
- Confirm the unit's record of reliability to ensure it can become the workhorse the operator requires.
- Specifications should include casters and quick disconnects for installation. This will assist in unit maintenance and cleaning/sanitation.
- Test the operation's water and install the correct water treatment system to ensure the combi oven functions properly.
Specifying Mistakes to Avoid
- Operators should make sure there is a place for the combi in the kitchen. If space is limited, consider a countertop unit or stackable model that provides higher production in a smaller footprint.
- Assess the operation's future needs. The combi should provide flexibility, allowing it to roll with the changes as menu or service style evolves.
- Because combi ovens are complex pieces of foodservice equipment, assess the skill level of the culinary staff that will use these items. Some ovens are geared toward more experienced kitchen personnel. Training sessions may be necessary.
- Protect this investment with the right water filter system.
New & Notable Features
- Some ventless hood systems allow electric combis to be placed virtually anywhere.
- Innovative features include cleaning systems, browning controls to add color to food and smoking capabilities that use real wood chips.
- Some higher end manufacturers offer multishelf timers with 200-recipe programmability, intuitive graphic controls and on-board diagnostics.
- 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.
When to Replace
- Wear and tear: The service life of a combi depends on how well the foodservice operator maintains the unit. Failure to provide the proper attention to either the boiler or steam generator will prevent the unit from operating efficiently.
- Pricey repairs: For out of warranty units, cavity rust, weld cracks and insufficient steam production may
- indicate the need to replace a combi oven.
- Major malfunctions: A boiler failure or performance issues with technological components, such as the circuit board, can be pricey, and therefore cost prohibitive to fix.
Foodservice operators need to pay special attention to the cleaning and maintaining of their combis ovens, due to the units' many components and sophisticated technology.
Six basic maintenance tasks can help extend a combi's service life. Please note that the following is a list of general maintenance requirements. The manufacturer's recommendations and requirements should always be followed.
- Clean combis daily to ensure food safety and sanitation needs are properly met. To make this process easier, some models provide a self-cleaning feature with push-button operation. Operators generally do not use cleaning solutions with these units.
- Use only approved cleaners to clean the cavity. This will prevent rust buildup. Keep in mind that some models recommend using special tablets rather than chemicals.
- Boilerless combi ovens do not require descaling maintenance as required with ovens that have boilers.
- Regularly analyze water used for steaming to ensure it falls within the manufacturer's specified guidelines.
- Use the correct water filter or run the risk of compromising the combi oven's service life.
- Regular deliming is a must, since lime will reduce the unit's heating ability.
- Although convection ovens and steamers are Energy Star rated, at press time combi ovens were still being evaluated.
- Recent systems allow operators to tailor the amount of steam created to the type of product cooked.
- New combi oven technology reduces energy and water usage, while increasing production rates by 40 percent to 60 percent.
- Steam generator models, which formerly used as much as 40 gallons of water an hour, now use about half that amount.
Editor's Note: FE&S thanks William Bender, FCSI, of W.H. Bender and Associates for assisting with this article.