Lunch in five?
By Andy Coghlan IT COULD soon be possible to produce gourmet meals with undreamt-of speed. By combining a high-speed airflow system with microwaves, a new oven roasts chickens in four minutes, does vegetables in just 100 seconds and browns a 500-gram prime steak to perfection in little over three minutes. And all this with energy consumption a third that of a normal oven. Behind this kitchen revolution is the world’s first “turbo-driven” domestic oven. Its designer, TurboChef of Dallas, Texas, says that it cooks food 10 to 15 times faster than normal ovens and three to five times as fast as a microwave. TurboChef already produces a commercial version, and a domestic oven will be launched next year by Maytag of Newton, Iowa. The oven uses a blend of conventional heat and microwaves. Jets of air heated to up to 260 °C blast down from the roof of the oven towards each food item at high velocity (see Diagram). “It surrounds the food in a shroud of hot air,” says Des Hague, head of the team developing the oven. At the base of the oven, the wave of air is sucked around the food. This “shrouding” of the food in heat overcomes the usual escape of heated air away from the food to cooler parts of the oven. “With the turbo system, there’s nowhere for the heat to go except in the food,” says Hague. The force of the jet of air prevents a cool boundary layer of air forming around the food, which slows cooking in conventional ovens. At the same time, the food is heated from below with microwaves. “These agitate and heat the water molecules inside the food,” says Sloan Gaon of TurboChef. The combined assault cooks food from the outside and inside simultaneously, he says. Pre-programmed routines squeeze conventional cooking procedures into a fraction of the usual time. To cook steak, the turbo-oven first “sears” the meat with a high-velocity blast of air, mimicking a very hot grill. Next, microwaves cook the steak inside, as if it had been moved lower in the grill. Then a jet of air browns the steak. British TV’s celebrity cook Delia Smith welcomes the device, but cautions against sacrificing flavour for speed. “It might be convenient, but we should always remember that the science of cooking involves time, and that’s what brings out flavour,” she says. “If it’s really quick,