As the trend toward using cold cooking suites or cold stoves heats up across Europe, an increasing number of high-profile chefs in the United States are beginning to embrace the new technology. At the same time, several national and regional chains either are testing the practicality of cold ranges or are already using them.
Cold stove is a term for a kitchen cooking device without an open flame, which produces high amounts of excess heat. It typically refers to induction ranges, but it also can include electric plancha grills, miniature combi ovens, food finishers and salamanders. In Europe they also are referred to as “comfort stoves.”
Whatever they’re called, though, the interest in cold cooking is exploding in virtually all market segments. What is driving the trend? There are several factors:
• Improved quality, efficiency and reliability of induction equipment, and expansion of induction technology into griddles and planchas.
• Increased use of flat grills like griddles and planchas over high-temperature broilers.
• Availability of compact combi and speed ovens that produce little external heat and integrate easily with the main cooking area.
• More accurate temperature control provided by the technology, as well as a more pleasant cooking environment.
• Expanding interest in sous vide.
While embraced by the French, original demand for the cold stoves came from Switzerland, Austria and Germany. Cold stoves now represent 70 percent of the leading French cooking equipment manufacturer Bonnet’s production for the European market.
The common cold stove’s configuration includes an induction cooktop, planchas, a sous vide area, a heated work surface and a section for plating. The suites or lines are all electric, with no gas functions.
According to Guillaume Durand, Bonnet’s director of sales for North America, the benefits top chefs find in cold stoves include:
• Extremely precise temperature control and reduced prep times. High-power induction boils 2 liters of water in 4.5 minutes, which compares to 8.5 minutes on open burners.
• A reduction in end-of-service cleaning time by 60 percent — ovens can be cleaned immediately because there is no cool-down period and nothing is burned on.
• An optimization of energy costs. Cold stoves have 90-percent efficiency, with up to a 40-percent drop in the kitchen temperature, which translates to lower make-up air requirements and reduced heating and air conditioning demands.
• An average of 30 percent less exhaust power required in the kitchen.
• A potential reduction in duct-work sizes, making it easier to install in older buildings.
• Instant heat to pots and pans, provided by induction, leading to no accumulated heat coming from French tops or char grills. Low heat means less sweat and greater chef comfort.
A safer kitchen environment
With a cold stove, the kitchen environment is safer and contains less risk of fire or injury; moreover, it has a reduced carbon footprint. In addition, the range top is cool and flat, so chefs can set up their mise en place right on the stove.
Induction units — even when turned up full — without a pan in place use next to no power. Energy consumption drops from 3.5 kilowatts or 5 kilowatts to about 60 watts — enough to power the fan and LED display. If a pan is not detected on the equipment within 10 minutes, the unit goes to sleep, the fan shuts off, and consumption drops to only 6 watts — enough to power the LED so an operator will be alerted that the unit is on. All of this contributes to less heat emission.
Gas ranges are only about 35 percent efficient, with 65 percent of the heat generated being wasted as heat gain to space. At 95-percent efficiency, the loss from each induction burner is only 44 watts per hour, which is just 150 BTUs per hour. The gas burner, by contrast — if left on full power — is losing 20,150 BTUs per burner per hour. This represents a huge difference, and is the reason why restaurant kitchens get uncomfortably warm.
A 3.5-kilowatt induction burner is the equivalent of a standard 30,000-BTU gas burner, and a 5-kilowatt induction burner’s power exceeds that of the largest gas-stovetop burner. Additionally, a 3.5-kilowatt induction burner only consumes 875 watts an hour.
Pairing a cold range with an on-demand hood is an energy-saving dream. Only a fraction of the standard requirement for cubic feet per minute is needed because there is no effluent. Without a 65-percent waste of heat, there are additional air conditioning savings.
The “wet” nature of gas combustion is another important element to consider. It’s not just heat that contributes to an unpleasant atmosphere — gas cooking produces more humidity than induction cooking, which further adds to operator discomfort.
But cold cooking does have some drawbacks.
In high-volume situations, a cold stove may have to be larger than a traditional gas stove to offer equivalent production. Shelves or pot racks hanging over a cold stove are discouraged, as pots and pans may fall on the induction glass. Further, high-power induction ranges typically are not installed over convection-oven bases like gas ranges; the induction generators will last much longer if they are not sitting on top of a hot oven. However, installing refrigeration under induction units is fine. Additionally, unless you’re using equipment with built-in grease extractors like speed ovens or ventless hoods, cold cooking devices still require exhaust hoods, and surface cooking requires a fire-suppression system.
Cold ranges aren’t for every venue, but they have strong benefits that make them worthy of consideration.
Foster Frable is a founding partner of Clevenger Frable LaVallee Inc., a foodservice consulting and design firm in White Plains, N.Y. He has designed more than 400 foodservice projects, including restaurants and operations in hotels, colleges and more. He can be reached at [email protected].