The perfect combination

RV Rutland's range comprises 12 combi-ovens, with all the latest versions incorporating touchpad technology for temperature and time control. They all have rapid-cooking systems, double-glazed doors, indirect heating, adjustable distance between grids, mixed cooking with fully adjustable steam, and optional core probes and hand showers.

Dawson's new range for 1999 features the compatible Lainox Cucinatore combi steamer and blast-chiller/freezer. Customers have a choice of three controls on the ovens, from simple mechanical controls to sophisticated programmes, including full compatibility with remote PC stations for programming and conforming to Hazard Analysis, Critical Control Points requirements.

Milestone Catering Equipment has launched a range of Franke 2005 combi-ovens. They range from the five-rack GN2/3 up to the 20-rack GN2/1 sizes in both electromechanical and fully computer-aided models. All feature climate control, claiming reduced weight loss of up to 50% and power and water savings of 60%.

Bonnet's Equator ovens are fitted with control knobs instead of panels as, according to the manufacturer's research, customers prefer them. Each knob corresponds to a clearly identified function, and efficient ventilation optimises regularity of heating with one fan per six-level oven, two fans per 10-level and three fans per 20-level.

Amana's UCA 2000 Convection Express combi (pictured) offers 2,200W of convected heat and 1,000W of microwave power, with a 24-program touchpad and four cooking stages.

The Winston C-VAP from Bakers Pride claims a patented method that surrounds food with vapour to prevent moisture loss. It can roast, steam, bake, proof, slow- or fast-cook or regenerate up to 100lb of frozen product to 165ºF in 35 minutes.

Angelo Po has six sizes of combination oven on offer featuring a variety of controls from a single switch to touchpads. Sales of Viscount's Chefaire ovens have swung towards 60% manual models over the past 12 months, partly due to cost but also because chefs want things to be simpler. Wiesheu Wiwa has recently added the D range to its existing product lines, replacing knobs with touchpads.

Combi-ovens started appearing in commercial kitchens a little over 20 years ago and are now firmly established among the ranks of prime cooking equipment. Highly sophisticated and often mind-boggling in their computerised applications, they offer chefs a range of cost-saving features combined with faster cooking and benefits such as less shrinkage of meat.

A combi-oven is, as the name implies, an oven which cooks by a combination of steam and dry convected heat. It can be used to roast, boil, braise, steam, brown or regenerate food and, on average, is 25-30% faster than a traditional oven, providing all-round evenness of cooking by using a cavity fan and hot, humid air.

In a traditional oven a 5kg joint of meat would need 40 minutes/kg to cook - a total cooking time of 180 to 200 minutes. In a combi-oven the same joint would take 25 minutes/kg, 125 to 140 minutes in total.

Buying the oven raises many questions. What size do I need? Should it be gas or electric? Do I need a programmer? Will I use a meat probe? One thing worth bearing in mind is that with one oven performing so many functions, you could be left with no means of cooking anything if it breaks down. Two smaller ones might be better than one large one.

As for the choice between gas and electric, gas ovens are more expensive to buy, but in most cases they are cheaper to run. So it follows that the more you use it, the more cost-effective a gas oven could be.

For best results, experts advise choosing an oven with a steam generator and one that is compatible with blast-chilling systems. Heat-up time is another factor to consider, and will vary with each model. Siting of controls and ease of door opening are other important considerations, so make sure they're as convenient as possible. Manufacturers have tried to make the controls less complicated, many of them switching back to knobs instead of control panels, and most offer full training, often at the caterer's premises.

Other major features to look for include a quenching system to prevent flavour transfer and to stop steam from rising above the desired level; the capability of pre-heating to 300ºC; double-glazed doors, adding an important safety factor; and an integral hand shower that makes cleaning easier. A food core temperature probe is also essential, and some manufacturers recommend connection to softened water to prevent scaling.

The versatility of the combi-oven makes it suitable for virtually every kind of catering situation, especially where space is at a premium. On Hoverspeed's cross-Channel SeaCat ferries, which have just upgraded their restaurant service, Hobart has installed a CSO423 combi-oven as part of a package for the galley.

The new oven replaces a smaller combi and microwave oven. "One of the main things we wanted to do was increase the amount of baking we can do on board," says Hoverspeed's food and beverage manager Kevin Tettmar. "Previously, fresh Danish pastries and baguettes were loaded at either end of the crossing, but there is still a great deal of difference between a product that is a few hours old and one that is genuinely fresh baked."

Space and weight restrictions in the galley were considerations for Hobart but the CSO423 offers all the features of Hobart's larger models, accommodating up to four standard 2/3 gastronorm trays. The oven conforms to marine safety requirements with a double stainless-steel skin keeping the external temperature low in case somebody touches it during operation.

Convotherm has also gone to sea, this time on board Royal Navy frigates. Installed by marine specialists Kempsafe, six- and 10-grid Convotherms have been fitted on the vessels. "Convotherm's straightforward electrics make them much easier to maintain than some other makes," says Kempsafe managing director Colin Packham. "As there is no neutral on board ship, the electrics in any piece of equipment have to be modified. We usually have to adapt equipment to run on 440v, three-phase, three-wire supplies, but Convotherm always carries out all the modifications for us."

Increased safety measures also have to be considered, with all units being safely bolted down. The frigates have six-grid combis on top of 10-grids, maximising use of restricted space. Other modifications include a wire safety mesh across the front of the glass oven doors and door stays to keep the doors locked in position when open.

At sea but not going anywhere is HMP Weare, the floating prison at Portland, Dorset, where Rational has installed four CM-201 large combi steamers, each capable of preparing up to 300 meals in a single session, housing up to 20 1/1 gastronorm trays.

"We use the ovens for the full range of cooking," says catering manager Mick Master, who has served in naval establishments at sea and ashore for more than 22 years. "Menus tend to be on the conventional side with standard meats, pies, curries, vegetables and most types of potatoes."

Marine specialist Catershop has put two Mareno combis on to a floating oil rig. One is welded to a cantilevered top to form part of the main cooking island, with the other in the rig's bakery. "Everything must be sea-fixed and few manufacturers produce combination ovens suitable for sea use," says Catershop's Richard Todd. "They must be able to work from generated power and racks must be fitted so that they cannot fall out."

Back on dry land, the Royal Lancaster hotel in London has purchased five Elro combis over the past 10 years, which executive chef Remy Fougäre uses "for everything". The banqueting department serves 1,500 meals almost every day, and frequently more. While the chef particularly appreciates the ovens' capacity and the design of the regeneration trolleys, chief engineer at the hotel Dick Smith is particularly impressed with Elro's back-up service. "They are not cheap," he says, "but you get what you pay for."

Capacity is a vital consideration to Anglia Crown which, on taking on the running of the former NHS central production unit (CPU) at Severalls Hospital, Colchester, in 1992, replaced the existing equipment with five 40-grid Grundy/Kuppersbusch CEC 220 combi-ovens.

"Volume and throughput were, and still are, vitally important," says Bob Baggalley, director of Anglia Crown. "The existing 40 gastronorm-size ovens just weren't cooking evenly, which meant constantly turning and changing products from shelf to shelf." The caterers have now moved to their own purpose-built, multi-million-pound CPU where the combis fulfil a vital role. n