The use of combi-ovens and blast chillers to precook dishes and suspend them at the point where they are freshly made has been revolutionary for chefs catering for large numbers. Stuart Ferguson surveys the latest equipment in the field
I remember a time when the definition of "cook and chill" was to go into the kitchen, work a busy service and then go down to the bar and sink a few Stellas. Nowadays it signifies what is, in effect, a very simple procedure for the delivery of meals, and one which has revolutionised large-scale catering.
For the process to work, you simply need two pieces of kit: a blast chiller and a combi-oven. The title explains the procedure to an extent, but omits the regeneration part. I guess "cook, chill and regenerate" just isn't catchy enough.
Simply put, you first "cook" your food, then blast "chill" it. The blast chilling is important, as it lowers the core temperature of the food quickly and safely while helping to retain the nutritional elements. All that is left to do is plate the food and regenerate it - more often than not back in the combi-oven.
"A well run cook-chill operation can provide the caterer with a flexible way of producing hundreds of meals in less than 15 minutes, and the market for cook-chill is widening," says Ian Osborne, group managing director of Enodis UK. "It used to be reserved for large hotels or conference venues. Today, however, it is popular with smaller hotels, pubs and golf clubs, where the flexibility to cook multiple portions in just 15 minutes is imperative to the success of an event. The other major factor is that combi-ovens are becoming smaller, making them a viable option for the smaller operator."
Enodis UK supplies the Convotherm range of combi-ovens, including the Convotherm OES6:06, which, it claims, has the smallest footprint of any combi-oven in the market. The company has now introduced Convochill, a range of blast chillers that link perfectly with the ovens to create a complete cook-chill system.
Additionally, Convotherm ovens now have an overnight cooking mode in the standard programme setup. This enables the chef to use the oven during off-peak periods and releases the oven for prime cooking during the day. Furthermore, it means that energy costs can be saved by using off-peak periods.
Nick Bates, research and development chef for Angelo Po UK, agrees that a cook-chill system isn't just for large-scale catering. "Cook-chill is becoming increasingly popular in smaller venues, such as restaurants that have a small function room as well as a main restaurant," he says. "All the prep can be done in quieter times, reducing the pressure at service so more choice and better quality of food can be served at optimum temperature for safety. With kitchen space being tight, this all can be done by a stacking configuration of a 10- or six-grid combi on top of a five-grid blast chiller."
The company's range of CombiStar combi-ovens are compatible with its ChillStar blast chiller models, which feature the patented Intelligent Food Recognition system. A probe containing three sensors continuously takes the temperature of food just below the surface and ensures that the core temperature is reduced to 3°C in the quickest possible time without freezing the food surface. The range is complemented with trolleys that decant directly from CombiStar to ChillStar, making it time-saving and user-friendly.
The time-saving element of cook-chill is not the only advantage. "Using a blast chiller and regenerator means that caterers can cook in bulk and plate up at their leisure," says Graham Russell, Lainox brand development manager for Dawson Foodservice Equipment. "This is a much more cost-effective and efficient way of operating, as it allows for better kitchen organisation, more time to care for service, lower power consumption and lower food waste. Labour costs are reduced as well, because the plating-up process can be done ahead of time."
Developed in Italy, Lainox equipment offers the Lainox Cooking System for cook-chill operations, which includes ovens, holding cabinets, blast chillers and regeneration cabinets. These appliances allow the chef to cook, blast chill and then regenerate food, whether in bulk or plated.
The integrated system, purposely designed for a deferred service, means it is ideal for large occasions, such as weddings and banqueting events. Preparing food well in advance frees up the chefs, and transporting the food to the service area where plates ready for finishing are reheated requires little time, ensuring diners receive impeccable meals.
Furthermore, the Lainox Heart ovens are equipped with an Autoclima function, which enables chefs to control the amount of humidity within the oven cavity when reheating food and eliminates those annoying pools of water on the plate. The Lainox regeneration trolleys also add a controlled amount of humidity to the food that is being reheated. This guarantees perfect reheating, without drips on the plate or dried-out food, whether serving 100 or 1,000 covers.
Using a turbo heat generator and multi-fan technology, E&R Moffat's Chillogen banqueting trolley takes the cook-chill routine to another level of efficiency. Chillogen combines the functions of a chilled storage unit and a regeneration oven in one appliance and cuts out two stages of food handling during the cook-chill process, saving both time and space in the kitchen.
With the Chillogen, once the cooked food is plated up it is loaded straight into the trolley, where it stays until it is served directly to the table. The plated food is quick-chilled, stored and automatically regenerated at a preset time.
The trolley is available in two models, the 60 and the 90, making it possible for a single unit to cater for events with up to 60 or 90 covers using 10in plates. The Chillogen trolleys are fully mobile as well, so can be pushed from kitchen right to the dining area, where they are simply plugged into two 13amp sockets.
The high-volume hospital kitchen is another type of operation that can benefit from the process - and one for which the Air-O-System line from Electrolux provides an integrated cook-chill system.
It combines an Air-O-Steam combi-oven (which limits food weight loss and uses less fat) with an Air-O-Chill blast chiller/freezer to simplify the process and save time and energy.
The combi-ovens use Air-O-Clima technology to provide the perfect atmosphere for all kinds of cooking, while the Air-O-Flow process provides uniform heat distribution.
Available in gas or electric versions, the combis offer precise control through a six-point multi-sensor, an automatic built-in cleaning system and a half-power setting.
Air-O-Chill's preprogrammed chilling and freezing cycles comply with UK and French hygiene regulations and allow customised chilling, freezing and holding programmes. They can chill food from 90Â°C to 3Â°C in less than 90 minutes and freeze it from 90Â°C to -18Â°C in less than four hours.
Of course, banqueting is where the cook-chill system has had the largest impact. The four-star Hotel Kilkenny, located near the heart of the city of Kilkenny in Ireland, recently refurbished its banqueting facilities, which are now capable of hosting events for up to 800 guests.
A colleague recommended Rational to head chef Stephan Koch and on investing in a SelfCookingCenter (SCC), he was an immediate convert. "There's more than just better food quality with the SelfCookingCenter," explains Koch. "It also saves time. Even a banquet with more than 200 guests takes only eight minutes to regenerate."
Another added advantage to the SCC's speed is the flexibility that it offers the kitchen when it comes to timings. Let's face it, when was the last time you did a function that stuck to its timings like clockwork? "As the preheating and cooking time is very short," says Koch, "we can be very flexible, even if the main course is required earlier or later than expected. We normally prepare banquets the day before, when there is plenty of time. The meals are plated up, put in a special trolley and kept cool until the event. As the finishing takes only eight minutes, we can adjust our timing to whatever is going on at the event, for example if speakers are running late. Even though there might be up to 800 guests to serve, the kitchen doesn't get stressed."
And it's made for big savings, too. "We've saved a lot in staff costs and at least 15% on food shrinkage. Before we got the Rational we needed eight chefs for a 200-person banquet. Now we need only three."
There are many advantages to a well-designed banqueting system, and Hobart's regional catering specialists are on hand to help the increasing numbers of caterers who want to make the switch from more traditional ways of cooking.
Pete Evans, product development manager for Hobart UK, says: "Our range of convection steamers - ranging from 10-grid right up to 40-grid models - is very versatile and can suit different sizes of operation, offering a plated banqueting system that can be tailored to the needs of any caterer. Chefs can very finely tune the amount of steam required to regenerate different dishes so that there is no compromise in quality."
"Part of the draw is the sheer practicality of a banqueting system. It allows large numbers to be served quickly with minimal hassle for chefs and waiting staff," says Evans. "It can also mean that it's not always necessary to pay top-flight wages for the expertise of a head chef all night - the oven can be preprogrammed by the chef to guarantee the same results are achieved throughout service. As the food is prepared in advance, they can instead spend their time more profitably prior to service in the more creative processes."
Key maintenance points
•To ensure that core food temperatures are reached in the cooking and chilling processes, it is usual to use a food probe that displays the core temperature on the oven or chiller readout. Because food probes are easily damaged, it's sensible to keep a spare probe available for a service engineer to fit without delay.
•Maintaining the correct temperature throughout the process is crucial. So it's vital that the temperature readout on every piece of equipment is working correctly. This means regularly checking it against an independent temperature device. A service engineer will always carry one if you are in any doubt about the correct temperature reading.
•There should be no unnecessary delays between each process, so having a regular check of prime cooking equipment, blast chillers, sealing machines, mobile trolleys and regeneration ovens is vital. Gas-fired equipment must be checked at least once a year for safe operation, and refrigeration equipment needs at least one condenser clean each year.
•Electrical safety is also crucial, particularly where equipment is being moved about. Check cables and plugs for signs of wear or damage every day. An electrical check to ensure that equipment is properly earthed and insulated is essential at least once a year.
•When using a number of mobile trolleys for distribution, each trolley must be checked to ensure it complies with temperature guidelines and can retain the heat or chilled temperature until service. If door seals are damaged, or control boards are faulty, take the trolley out of service until it's repaired. Check that the doors close properly each time before loading the trolley with food.
•Mobile trolleys can be dangerous when being pushed or towed. So every time they come back to base, check the wheels and towing mechanisms for signs of damage. If a trolley has been bumped against a wall, it's better to have an engineer check it before it's used again.
Source: Serviceline (01438 363000,www.service-line.co.uk)
Angelo Po UK 0870 460 6750 www.angelopo.net
Dawson Foodservice Equipment 01226 350450 www.dawsonmmp.co.uk
Electrolux Professional 0121-220 2800 www.professional.electrolux.com
Enodis UK 0845 370 4888 www.enodisuk.com
E&R Moffat 01324 812272 www.ermoffat.co.uk
Hobart UK 0844 888 7777 www.hobartuk.com
Rational 01582 480388 www.rational-uk.com
Valera 0845 270 4321 www.valera.co.uk