What’s Cooking?

Feb. 20, 1998
Cooking-appliance technology is starting to show some sizzle.

James Braham
Senior Editor

Ever since the microwave oven first appeared in the 1950s, major innovations in cooking appliances have been on simmer, so to speak. There have been some recent significant advances — in particular, the smooth glass electric cooktop — but true technological breakthroughs have been rare.

Now, however, the industry shows signs of starting to sizzle. A few innovations, mainly on the gas side, are on the back burner and promise to find their way soon to market. And several new appliances on the market offer interesting and exciting features.

In fact, Karla Lynn, director of brand development for Amana Appliances, predicts that “innovations in appliances in general over the next several years will come in cooking. The one thing we don’t have enough of today is time, so I think you will see a further increase in people eating out, and bringing meals home. The next real issue in cooking at home will have to involve speed, along with easy, convenient, one-touch type of cooking, so you can produce quality meals quickly with less fuss and bother.”

The gas industry and major appliance manufacturers have been working on their version of a smooth, easy-toclean cooktop with radiant gas burners below glass. Schott Corp., the Yonkers, N.Y., marketing arm of Schott Glaswerke, Mainz, Germany, is working to adapt its Ceran glass ceramic, now used in electric cooking surfaces, to gas cooking. Ceran’s zero coefficient of thermal expansion means it won’t expand or contract in heat or cold, and thus won’t crack or break. The material can withstand temperatures as high as 1,400°F for 6,000 hr, says George Rochler, Schott’s project manager.

The project is still in development, but it’s getting closer to market, according to Rochler. “It’s an evolving technology, but right now we can attain the same cooking performance as today’s fastest electric radiant elements and also offer the sleek appearance and cleanability of smoothtops,” he says. The major engineering challenge to “gas under glass” has been retaining the key advantage of gas: quick response on startup and adjustable input.

Schott is using silica carbide as a fiber mat material, which allows for infrared radiant applications, Rochler says. “Imagine a felt pad with lots of space and little cavities. By feeding a premix of air and gas into this silica carbide fiber mat, encased in a chamber which could be round like a cooktop burner, you have an infrared radiantgas burner. The flames aren’t blue or atmospheric in type because they’re too small to see, but through the glass you do see a red glowing like on an electric element.”

This new approach to gas cooking isn’t limited to gas under glass, says Rochler, noting it would work on a cooking surface with regular atmospheric burners. “Using Ceran as the cooking surface, a manufacturer can combine the benefits of gas under glass, cleanability, appearance, and low simmer capability with open-flame burners for blackening, very hot frying, or even wok cooking. In fact, adding radiant, halogen, or induction elements to the same cooking surface is possible.

“The blending of gas and glass-ceramic technologies — called gas through the glass, where the gas is an open flame — has another benefit,” the Schott manager continues. “In current open-flame burners, with the typical cooktop stainless steel or porcelain or even tempered glass, the burners and grates are high above the flame. Because Ceran has a zero coefficient of thermal expansion, the open-flame burner can now be much lower, all the way down to the surface of the glass, and even sealed.”

One of the most interesting next-generation technologies drawing nearer to market is the Smart Cooktop developed by Arthur D. Little’s R&D unit and then implemented by Eaton Corp.’s Appliance Div. in partnership with the Gas Research Institute. The Eaton unit has since been acquired by Siebe Corp. of the U.K., which is promoting this technology to American appliance manufacturers.

This advanced gas cooktop consists of an electronically controlled valve that sets flame levels, a burner with an integrated temperature sensor, and a control algorithm that monitors heat entering the food and modulates the flame so the pot or pan won’t burn or boil over.

“This is different than anything on the market,” explains Jim Jaeschke, research manager at Eaton’s Innovation Center in Milwaukee. “You can put a pot on the burner, set it for boil, and it comes very quickly to boil level. Then the flame is automatically reduced and regulated at boil level.”

This is all done through a sensor touching the bottom of the pot, which also can detect if the pot is empty, or if there is no pot on the burner. The cooktop automatically measures the temperature 5 times/sec and pulses the flame by raising it to full blast and then lowering it halfway every 15 sec. Besides absolute temperature, the sensor measures the rate of temperature change, the phase relationship (or time delay) between high flame and temperature increase, and the difference in temperature between high and low flame. All this information goes into the fuzzy-logic processing that determines whether the pot is boiling or not. The Smart Cooktop burners are sealed, and the electronic controls can be located anywhere, meaning the traditional knobs on the front of the range would no longer be necessary.

In another high-tech project, Maytag Appliances recently began a joint venture with TurboChef Inc. to evaluate the feasibility of adapting the Dallas company’s high-speed commercial cooking technology to home use. TurboChef cooking is used by fast-food operators to prepare food 10 to 15 times more efficiently and quickly than conventional commercial ovens, according to the company. Examples: chicken breasts or cheeseburgers take only 55 sec and pizza 75 sec to go from the refrigerator to the plate.

Through sophisticated computer controls, TurboChef’s ovens transfer heat from rapidly moving air to the food. As a result, food is evenly cooked throughout and browned or crisped on the outside to ordered specifications, and natural moisture is retained, the company says.

This heat-impingement system differs from air-impingement cooking in which jets of rapidly moving hot air strike food from above and below, causing the air to rebound and create turbulence, TurboChef President Philip McKee explains. With his system, heated air hits the food only from above. An air deflector under the food creates a vacuum, suctioning air out from the bottom. “After the air hits the food,” says McKee, “it tends be drawn across the top of the food and then across the underside in a constant heat-transfer relationship, and then out.”

With TurboChef, one can bake, broil, grill, rotisserie, steam, fry, toast, and poach in one 9-ft2 cooking footprint. And microwave cooking from below the food can be added to make the process even more effective, Mc- Kee says.

Maytag is evaluating this technology “to make sure there’s a market and that consumers find it appealing,” says Mark Buss, vice president and general manager of cooking. The system would need to be precise, he stresses. “If it takes only 55 seconds to cook a chicken, what happens if you’re 10 seconds off? The results could be ugly,” Buss cautions.

Through its new Blodgett division, which makes steam ovens for commercial use, Maytag also is researching use of steam cooking in the home. It is used primarily for pastry. Steam (or moisture or high humidity) in the first 7 to 8 min of cooking lets pastries rise higher, accounting for the fluffy croissants and mammoth muffins from bakeries.

Amana’s new Wave Oven represents innovative cooking technology already on the market. It uses radiant energy to enhance food quality while reducing cooking time, the company says. Eight 700-W halogen lamps in the upper and lower sections of the oven generate the radiant energy, and no preheating is required. This immediate, intense heat cooks in one-fourth to threefourths the time of conventional methods, depending on the item, Amana claims.

The Wave Oven resembles a microwave in size and shape, but differs in materials and principle. This is thermal cooking, so the unit is made of metal, rather than plastic. And as a thermal oven, it heats the air or utensil placed inside, whereas a microwave penetrates and heats food directly. “Microwaves offer speed but often inconsistent cooking performance. The Wave Oven gives roughly the speed of a microwave but the performance of a regular thermal oven, so you can grill, broil, bake, and sear, which a microwave cannot do,” says Amana’s Lynn. And unlike a microwave, it requires no more time to cook several items at once.

While halogen represents a simple heat source, the electronic controls and computer algorithms involved are complex. The upper and lower lamps cycle on and off as needed, depending on the intensity of cooking heat required. There are timer controls plus pre-programmed pads with 38 standard recipes. An optional scrolling message provides stepby- step cooking instructions. Users can also customize recipes for individual preferences, and store those patterns so they can be reproduced the same way every time, at the push of a button.

There has been a trend toward convection cooking, in which a fan circulates hot air around food for more even cooking and browning, as well as lower cooking temperatures and shorter cooking times. One of the most innovative systems is the “Third Hidden Element” from the KitchenAid unit of Whirlpool Corp. It’s an improvement upon traditional convection systems in which a convection fan works in combination with an exposed bake and/or broil element or wire, KitchenAid says. In that system, once the element heats, the fan circulates heated air throughout the oven cavity.

KitchenAid adds a third element, along with a series of molded-in baffles inside the oven. These “hide” the heating element so heated air circulates gently and evenly throughout the oven cavity without exposing food to direct radiant heat which can create hot spots, the company explains.

Induction is a high-tech method of cooking that offers instant and precise response, cleanability, and safety. With no flame, exposed coil, hot element, or residual heat, it is literally a “cool” way to cook. The only thing that gets hot is the special cookware, which is expensive, and the reason this form of cooking has never been a big seller in the U. S., where Maytag and its Jenn-Air unit are the only induction manufacturers.

Induction uses electromagnetic force to heat cookware of ferromagnetic material (iron, nickel, cobalt, or various alloys). When the controls are turned on, the coils produce a high-frequency alternating magnetic field which ultimately flows through the cookware. Molecules in the cookware move back and forth rapidly, heating it and thus cooking the food inside. The cooktop’s glass-ceramic surface is not affected by the magnetic field since it contains no ferromagnetic material.

Exciting innovations continue to come in microwave cooking, too. In these small appliances, food is cooked rapidly by the heat produced through the absorption of microwave energy — short electromagnetic waves — by water molecules in the food. Whirlpool Corp.’s new Sizzler oven, for example, features the company’s Accuwave system which distributes microwaves into the oven cavity from two points, instead of one as with most standard microwaves. This technology, developed by Swedish engineers (European consumers are more prone to pay a premium for appliance innovations), delivers more consistent cooking, the company says. Food defrosts, reheats, and cooks evenly without hot or cold spots.

With this technology, a megatron creates invisible rays and disperses them from the upper and lower right side of the oven, behind the control panel. This creates what Whirlpool calls “optimum wave performance” for the height and width of the cavity. These microwaves, phased so the top wave enters the cavity a split-second before the other, bounce back from the “wall reflector” on the left side of the cavity, providing a third horizontal wave or energy field for additional depth of distribution. Add the rotating turntable, and microwaves completely fill the cavity in a “3D” wave distribution for more even penetration of food.

To this Accuwave system Whirlpool has added a Teflon-coated sizzler pan, creating a “frying-pan” effect. It works like this: The base of the 12-in.-diameter pan is coated with an oiland- rubber-based material that attracts microwaves as they enter the oven from the lower inlet, transforming the microwave energy into induction heat and causing the pan to heat quickly, like a frying pan on a gas cooktop. The Sizzler holds the temperature at an optimum 410°F, and food is browned from both the top and bottom. With this pan, one can “fry” bacon, eggs, hamburgers, and crisp pizzas in a microwave.

Whirlpool is also test-marketing a futuristic control system called 6th Sense for the U.S. market. “It’s the most advanced sensor-type product in microwaves,” says Peter Smith, director of the microwave product team for North America. Already a success in Europe, this system is based on fuzzy-logic technology and uses a combination of sensors and human cooking experience to “guarantee perfect results,” according to Whirlpool.

While the fuzzy logic is complex, the user interface is extremely simple. Three one-touch buttons (Cook, Reheat, and Defrost) eliminate the need to input time, power, weight, or food type. The 6th Sense system uses three sensors, Smith explains. “A humidity sensor in many microwaves today senses the moisture coming off the top of food, and after a few seconds the microwave can recognize popcorn versus chicken, for example,” he says. “To this we add a weight sensor under the turntable indicating how heavy the food is, and a temperature sensor to determine how dense it is. Put those three sensors together and the microwave knows enough about the profile of the food to cook, reheat, or defrost it properly without you indicating what food it is.”

In this fuzzy-logic interface between human and computerized reasoning, a set of mathematical algorithms, based on human cooking experiences gathered through thousands of hours in a factory test kitchen, has been incorporated into the microprocessor. The “brain” of the microwave takes input from the sensors and continuously readjusts power and time during cooking.

The microwave starts off by sensing the condition of the food — weight, temperature, sensitivity to microwaves, condition at start such as frozen or fresh — and the expected result, such as defrost or reheat. It then begins the cooking process at a certain power. The oven also indicates the expected cooking time, which might change during the process. The sensors keep updating information and the “brain” adapts the time and power according to this new input.

Perhaps the most advanced microwave already on the domestic market is the new Multiple Choice oven from Sharp Electronics Corp., largest of the microwave manufacturers. Featuring the biggest interactive LCD display screen, with more than 200 illustrations, it guides consumers through over 100 recipes and lets them cook, reheat, and defrost hundreds of foods by using only four easy-selection buttons. It also employs sensors to automatically determine cooking times and power levels.

Sharp is among the microwave manufacturers that also offer convection microwave ovens. These combine the speed of microwaving with the browning and baking qualities of conventional ovens. In a convection oven, a built-in, high-speed fan circulates hot air around the food and throughout the cavity, so food cooks more evenly and browns, sealing the flavor and juices inside. These ovens also do straight microwaving to defrost and reheat.

Finally, Samsung Electronics America Inc.’s new elevating turntable raises and lowers food as it cooks for more uniform cooking. This unique Elevation Wave oven has an automatic gas sensor that calculates cooking time by food type through monitoring emitted vapors and gases. Samsung this year also introduced the first dual-cook microwave. Its elevated rack permits cooking two separate foods simultaneously at different temperatures and rates.

© 2010 Penton Media, Inc.

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