The range is perhaps the most versatile piece of cooking equipment in a commercial kitchen. It can be used to cook a wide variety of foods, primarily those requiring the use of cookware such as pans, stockpots and skillets. Many range units are also equipped with a conventional or convection oven located below the cooktops, which makes the unit even more versatile.
The range cooks food by transferring heat to the cookware, which in turn transfers that heat to the food by conduction. The cookware is heated either by an electric resistance coil, a gas or electrically heated solid-top element, or by coming in direct contact with the gas flame. Ranges can use a variety of cookware; however, when solid-top elements or resistance coils are used, it's important that the bottom of the cookware be flat to allow a good contact between the bottom of the pan and the elements. Rounded bottom pans reduce the amount of heat transferred to the pan.
Gas open-top units apply a flame directly to the bottom of the cookware. The chef controls the temperature by adjusting the height of the flame, which provides the visual feedback many chefs have become accustomed to. Gas units can typically be used with any type of cookware.
Solid-top units or flat-top units can be heated by electric resistance coils or gas burners. While these units take several minutes to preheat, they provide a very uniform temperature across the surface of the plate. Heat from the plate transfers to the cookware by conduction. Solid-top gas units are much less efficient than their open top counterparts because the plate must heat up before transferring heat to the cookware. Plus, with greater preheat time, these units are typically left on while other types of units could be turned off when not used.
Cooking on a range can be more of an art than a science. The experienced chef knows that it takes finesse to get the best performance out of a range. For this reason, less experienced food service operators can have a hard time producing consistent food product quality. There is no substitute for trial and error in learning how to adjust temperatures to cook properly and produce a tasty end product. In most cases, it's important that cookware have a flat bottom that makes good contact with the hot top or electric resistance coils.
Electric vs. Gas
However, there are many factors to consider when selecting a range: first cost, food preparation productivity, ease of operation, and heat generation in the kitchen, as well as the energy source used: electricity or gas. Keep in mind that energy use only accounts for 3 to 5 percent of a food service establishment?s total costs. So, while one fuel may be less expensive in a BTU to BTU comparison, the best choice in cooking equipment is the one which minimizes total operating costs, not just energy costs. Features that reduce labor costs or result in higher food product yield will nearly always outweigh any energy considerations. Make sure you include all of these factors in any equipment evaluation.
Let's take a closer look at the energy-use issues, remembering that comparisons should be made on the basis of similar equipment where only the energy input is being changed. Electric ranges are generally considered to be:
- More efficient, so they add less heat to the kitchen. This is heat that must ultimately be removed by the cooling system.
- Electric units are less prone to cause fires when grease spills over onto the range.
- They require less maintenance and less ventilation.
- Electric induction units offer the highest energy efficiency, come up to full temperature very quickly, and offer precise temperature control. These units are also safer for food service operators because the surface never gets hot.
Gas or propane ranges are generally considered to offer the advantage of a cheaper energy source. Some chefs prefer gas units because they can control cooking temperature simply by adjusting flame height. Also, because many chefs are trained using gas cooktops, they will most likely prefer a unit which most closely matches their skills.
Range equipment is available in many different sizes and configurations. Most units are 36 inches high and 30 to 32 inches deep and vary from 18 to 60 inches wide. Smaller units contain only 2 cooking elements while larger units can contain more than a dozen cooking elements. Ranges can be free-standing or mounted over an oven or cabinet base. Free-standing units often sit on a counter top and are sometimes called cooktops.
- Open Top
Several different types of cooking elements are available for both gas and electric energy sources. The most common is the open-top element.
Open top gas burners have a steel or cast iron grate that holds the cookware in place. Gas burners located below the grate produce a flame that directly contacts the bottom of the cookware. Open burners provide precise temperature control by adjusting the height of the gas flame and require no preheat time. Each burner is individually controlled by a gas valve located on the front of the unit.
The comparable electric unit is commonly known as the open coil hot plate. The cookware rests on an electric resistance coil, which when heated, transfers heat directly to the bottom of the cookware. These units usually take a few minutes to reach full operating temperature and a few minutes to cool down when turned off. Each cooking element has a separate thermostat controlling temperature.
- Hot Top
Hot-top ranges use the energy source to heat a thick metal plate rather than the cookware directly. These units are equipped with a 12 to 18 inch square plate about one-half to one inch thick. The energy source may be electric resistance elements or gas burners. In either case, the heat source heats up the metal plate. Cookware placed on this plate then heats by conduction from the plate. Since two separate stages of heat transfer are involved, these units are typically much less efficient than open-top designs. Plus, the plate can take 30 to 60 minutes to preheat and cool down. Therefore, chefs typically allow these units to continue operating even during slow cooking periods.
- French Plate
The French plate falls somewhere in between the open-top and the hot-top. They are most often electric. The cooking element is a round plate about 6 to 10 inches in diameter. The plate heats up from electric resistance coils or gas burners mounted to the bottom. The plate provides even heat distribution and each "eye" is controlled separately.
The electric induction range is significantly different from the other types of ranges. Induction coils located under a ceramic surface induce an electric current in the cookware. These units offer precise temperature control and are more efficient because they heat the cookware directly rather than the range surface. The ceramic surface is durable enough to sustain heavy use even when sauteing. These units are by far the most energy efficient type of range available.
Manufacturers offer a variety of optional features for the conventional range. Some units are combined with a conventional or convection oven, griddle or charbroiler. Some provide space for holding cooked food. Some manufacturers offer units with a combination of different cooking elements such as hot tops and open tops. Many ranges also have a shelf or a salamander broiler attached to the back of the unit.
- Heavy Duty
Heavy duty ranges are designed for large, heavy stockpots and other cookery. They are ideal for the high-volume production requirements in large restaurants and institutional and industrial kitchens. These units are typically smaller than conventional units, measuring 36 inches wide and are available in modular units with oven bases, open cabinet bases, or table tops alternatives. Configurations vary by manufacturer, but some include other features such as fryer sections, salamander broilers, ovens, and griddles.
Restaurant ranges are designed for a lighter duty cooking requirement than the heavy-duty range. Even though the total size of a restaurant range will generally exceed that of a heavy duty unit, they are more suitable for smaller operations and short order cooking. The larger size accommodates more cooking elements capable of supporting lighter cookware. Configurations vary by manufacturer. These units are available in lengths up to 72 inches and are often combined with a cabinet base or oven unit, salamander broilers, and griddles.
A variety of specialty ranges are available to suit specific food preparation needs.
The Chinese range is built for wok cooking. Some of these have water spigots and drain troughs to make cleaning easier.
A stockpot range is designed for very large stockpots and is typically only 24 inches tall to allow the food service operator access to the large pot.
Taco ranges are also available for the unique task of preparing the contents of a taco.
Electric induction ranges represent the latest in technological advancement for the kitchen. These units heat quickly, offer very precise temperature control, and are considered safer because the cooking elements don't get hot. These units are also the most efficient, transferring up to 90% of their energy to the cookware.
The initial cost of a range is rarely the most significant factor in making a purchase decision. Those who select light equipment due to lower cost often discover, after the fact, that these units are insufficient for the kind of production they had intended. A range should be chosen on the basis of the following six characteristics: capacity, versatility, temperature consistency, serviceability, ease and economy of required cleaning, and over-all dependability.
Here are some tips on how to operate the equipment in a way that saves money:
- Make sure the bottom of the pot rests flush against the heating surface.
- After the pot comes to a boil, turn the heat down to a level that maintains a simmer. Food will not cook any faster if you add more heat. That just wastes energy.
- Cover the pot with a lid to retain heat.
- Always cook at the lowest possible heat level that yields satisfactory food product.
- Turn the unit off, or at least reduce its temperature when not in use.
- For closed-top units, preheat only as needed.
- Heat only the section of the closed-top unit being used.
- Group pots on closed top ranges to use as little surface area as possible.
Here are some energy saving tips specific to gas equipment:
- Adjust the flame until it is entirely blue. A yellow-orange tip means you are using too much gas and some of it is not burning completely.
- Gas flames should just cover the bottom of the pot. Flames extending beyond the pot bottom are dangerous and waste money.