Always on the lookout for ways to improve the guest experience, one of the fastest-growing QSR chains in the country recently tested some new kitchen equipment. Already known for a great product, the chain wanted to deliver it faster and with greater consistency to meet customer demand for “on the double” service. 

After looking at a number of alternatives, the chain chose a clamshell grill. Although the switch from regular grills to double-sided cooking involved some process changes and shifting a few things around on the line, the new equipment has increased store throughput and delivers a more consistent product to customers in less time and in about the same space. Preliminary numbers also suggest the equipment is saving energy.

It might sound too good to be true, but it makes sense: If you cook both sides of a grilled item at the same time, you should be able to cut cooking time in half, effectively doubling your capacity. 

That’s not to say double-sided grills will cook everything, or that they’re right for every operation. But if your menu includes high-volume items that are consistent in thickness—burgers, chicken fillets, steaks, seafood fillets and sandwiches, to name a few—double-sided cooking could offer major benefits.

Two ways you can get into two-sided cooking are via light-/medium-duty countertop equipment and heavy-duty floor-standing equipment. Countertop equipment for the most part encompasses sandwich presses and panini grills (see sidebar, “Countertop Clamshells”). For our purposes, we’re covering heavy-duty two-sided grills that are designed to turn out the kind of volume you generate if you operate in a QSR or fast-casual environment.

 Full Contact, No Pads 

Double-sided clamshell grills use direct contact to transfer heat, although some specialty equipment uses non-contact, radiant top heat. The top cooking surface, called a platen, comes in contact with the food on the grill surface below. The platen typically is gimbaled in some way to keep it level when lowered onto products. By keeping the platen level, heat distributes evenly on the top of the products you’re cooking, so both sides cook at the same time.

Grills can be gas or electric, ranging in size from 24-72-in. wide. Platens on all models are electric. The most popular models are 24-in. wide with one or two platens and 36-48-in. wide with two or three platens. The grill surface is usually zone-heated to correspond with each 12-in.-wide platen so you can cook products at different temperatures every 12 in. 

Platens are counterbalanced, usually with springs, so they’re easy to raise and lower manually. The counterbalance also is designed to maintain even pressure of about 3 or 4 lb.—rather than the full weight of the platen—on the product. However, one manufacturer also makes a model with a weighted platen to compress a hand-formed burger into a patty of a specific thickness.

On most two-sided grills, the gap can be set from 0-1½ in. in increments of 0.01 in., giving you the flexibility to cook everything from burgers to pancakes and chicken patties to grilled-cheese sandwiches. Newer models coming out this year have an even wider 2-3-in. gap to accommodate more types of products, such as layered panini sandwiches, chicken breasts and seafood. 

Manufacturers use slightly different systems to level platens but design units to duplicate the precise gap each time the platen is raised or lowered. One uses a three-point frame of reference; sensors feed platen gap measurements to a microprocessor, so each time the platen is raised or lowered it duplicates the same gap. Another uses a patented, gear-driven “micro-leveler” that sets the platen at an infinite number of gap measurements, all the while ensuring level and even pressure. Yet another uses a four-bar linkage system to level the platen 3 in. above the grill surface and lower it onto whatever product you’re cooking—there’s no gap to set. The platen’s weight alone presses down on the foods. 

Automatic lifters do the work for employees, lowering the platen at the push of a button. You program cooking temperatures and times into the unit, and the platens raise automatically when the cook cycle is finished. These lifters are different from one maker to another, too. One uses air cylinders while another uses a linear actuator similar to the rack-and-pinion steering in your car. But all of them offer a way to take the guesswork out of cooking, improving finished product consistency. Autolift systems don’t add any inches to the depth of the unit.

You can program some units to cook to tight specs you set for your products. For example, all you have to do for a frozen chicken breast is program its thickness, cooking time and required internal temperature. All employees need to do is load the grill and press the program button. The grill will lower the top platen, cook the product from 0˚F to an internal temp of 165˚F and raise the top platen. Not only will the grill cook the product consistently, but it helps to ensure a safe internal temperature. 

Automation isn’t for everyone, but you still can improve product consistency by making sure the clamshell you choose has something as simple as a timer. Clamshells aren’t tough to raise and lower by hand; a timer can help ensure employees take product off of the grill when a cook cycle ends.

Have It Your Way 

As mentioned previously, you can configure clamshell grills just about any way that works for you: gas or electric, widths from 24-72 in. and as many or few platens as you need to cover every 12 in. of grill surface.

A couple of manufacturers make dedicated clamshell units, built to integrate the top and bottom from the get-go. Other grill makers have developed clamshell platens that can be added on their traditional open grills. You already may use a grill that can accommodate a platen, so testing and implementing double-sided cooking is fairly easy. Some of these “add-on-platen” styles also can be automated; others operate only manually. 

Electric models range in power from about 4kW per 12-in. section of cooking surface (for a total of 8kW when you combine grill and platen) to about 7kW (for a total of 14kW) depending on the model. Input on gas grills typically ranges from about 25,000-33,000 Btu for each 12-in. section depending on the make and model; each section has an electric platen typically in the 4kW range.

Manufacturers make a couple of different versions of each model to match common 208V and 240V service, and there are even 220V models if that’s what your local utility offers. Most also make a model to 380V, 400V or 415V for export—400V service is common in Europe—but you may be able to get such service in the U.S. 

Clamshells, by their nature, are efficient because they cook both sides at once, but some models are more efficient than others. The U.S. Environmental Protection Agency’s Energy Star program includes both gas and electric clamshell grills in its specs, so looking for the Energy Star label on a product can save you money on energy costs.

Look for even heat distribution on both grill and platen surfaces. Once a grill heats up, temperatures across the entire surface may even out somewhat, but with only a 12-in.-wide cook space for each platen or zone, you don’t want hot or cold spots. 

Burner design on gas models and heating-element design on electric models can affect heat distribution. Most electric models have tubular heating elements, although at least one line has flat elements. More significantly, heating elements maybe attached to the bottom of the heating plate on some models, which usually is not as efficient as embedding them in the plate. If attached, look for insulation around the element to help save energy.

Most, but not all, top platens are constructed with the heating elements sealed in die-cast aluminum. 

Temperature sensing also can affect heat distribution. It’s atypical to find anything but thermocouple sensors these days because they are the most accurate, although some inexpensive open grills still may use bulb sensors. However, the number of thermocouples, where they’re located and how they’re attached all factor in. Like the heating elements, thermocouples embedded in the grill plate, for example, will sense temperatures more accurately than those attached to the bottom of the plate.

On The Surface 

You can buy clamshells with several different surfaces: smooth, grooved, highly reflective and radiant. Likely most versatile is the smooth surface, on which you can cook everything from pancakes and bacon to burgers and quesadillas. A grooved surface, however, can give you “grill marks” on a product such as a chicken breast, steak or sandwich. A grooved grill surface also channels excess grease from a product into the grease trough. The highly reflective surface of one maker’s unit not only is easy to clean but saves energy, too, according to Energy Star, reducing radiated heat loss to less than 10% of a conventional steel plate.

Depending on your product selections, you can mix and match these surfaces, too. A 48-in. grill, for example, could have two smooth platens, a grooved platen and a portion of flat grill with no clamshell to accommodate a variety of foods and desired finishes. 

Manufacturers use different materials at different thicknesses in the manufacture of their grill surfaces. Thicker plates tend to take longer to get up to temperature, but distribute heat more evenly once they do. Thinner plates heat faster but could be prone to more hot and cold spots.

Makers typically use stainless or composite plates in thicknesses between 3/8-3/4-in. These typically are a combination of steel and galvanized aluminum that range up to about 5/8-in. thick. The surface, however, is polished steel, which makes it easy to clean.

Platens, on the other hand, can be stainless, coated steel or polished aluminum. To make cooking and cleaning easier, all manufacturers offer nonstick sheets to attach to the platens. In most cases, the sheets are made of Teflon, but at least one maker uses a reversible polymer sheet.

Sheets can be removed and washed at night if they’re not too worn; otherwise, they can be replaced. Typically, they cost anywhere from about $5-$10 and last from one to several weeks depending on a facility’s volume. While they represent an ongoing operations cost, the platens would be nearly impossible to clean without them.

The best way to find out which make and model works best for you is to test-drive a number of them. The Pacific Gas & Electric Co. Food Service Technology Center, operated by Fisher-Nickel, San Ramon, Calif., has performed a number of energy tests on leading brands; the reports are available at Remember, too, that changing to faster double-sided cooking may mean changing some processes and even kitchen layout so everyone can keep up. A little redesign may be well worth it. 

Lighter-Duty Double-Siders

Countertop clamshells, better known as sandwich presses or panini grills, share similarities with their bigger cousins, but you’ll see notable differences. First, they’re built for lighter duty. While many models will cook products such as steaks, burgers or chicken breasts, their primary function is grilling sandwiches on both sides at the same time. 

Sandwich presses often allow a gap as large as 4½ in. between cooking surfaces, offering versatility to grill everything from super-thin tortillas to thick sandwiches. The top platen is gimbaled to keep it level as it lowers onto products. It’s also counterbalanced so the platen manually raises and lowers easily. Platens maintain even pressure of about 3-4 lb. on the product. 

Countertop units generally range in power from about 1.7-2kW total, top and bottom. Split-top (two-platen) units and light-duty clamshell grills up to about 34-in. wide have roughly double the power with units using 3.6-6.5kW.

Like clamshell grills, you can spec sandwich presses and panini grills with smooth, grooved or even radiant surfaces. Radiant versions from a couple of makers put heat elements behind special ceramic glass, which cleans easily. Two manufacturers also have added microwaves to their radiant models; the combination of microwaves, conduction and radiant heat warms and toasts sandwiches in as little as 30 seconds. 

Most manufacturers make single and double or split-top models, and a few make even larger four-platen units. If you’re just starting a panini/grilled-sandwich program, offer catering or banquet service or serve on buffet lines, these smaller “clamshells” could be just the ticket.


Garland’s Master Series Gas Xpress Grill is a 2-sided cooking device with a gas-fired grill and 2 independently controlled 11 1/2-in.W electric top heaters. Each 12 in. of the grill has 33,000 Btu/hr. of heat input via natural or propane gas as well as a built-in pressure regulator, gas shut-off valve and separate programmable controller. The unit features die-cast aluminum electric top heating elements; a stainless front, top and sides; a multicolored LED indicator that identifies operational mode; and 4 swivel casters with front brakes. The unit is available in 208V/220V/240V, 1- or 3-phase and 380V/400V/415V, 3-phase models.

Keating’s Top-Side Cooking Head is available with a manual- or auto-lift platen. Double-sided cooking dramatically reduces cooking time by up to 60%; the unit cooks up to 8, 1/4-lb. burgers under each platen. The unit, in widths from 24-72 in. (30-in.D and 48 5/8-in.H with platen up), provides two-sided cooking with precise temperature control. Top-Side Heads can be mounted onto Keating’s gas or electric models, which are equipped with a Miraclean super-polished surface that has excellent heat retention and realizes annual energy savings of 32% over competitive units, according to the company. The Miraclean surface cleans up 44% faster than competitors, based on a University of Illinois at Urbana-Champaign lab test. The Top-Side uses a replaceable, polymer-coated nonstick cooking sheet that makes clean up easy, as well.

Lang’s 12-in. contact clamshell is electric, warmed with steel-sheathed infrared heating elements. Its 2-sided cooking reduces wait times and increases production. Mounted in a stainless hood, the clamshell is self-leveling from the fully closed position up to an approximately 3-in. maximum opening to cook a variety of products, such as tortillas, burgers, burritos and sandwiches. The top grill platen is 5/16-in.-thick steel for rapid recovery and 11-in.W x 21 1/2-in.D for a cooking surface area of 1.64 sq. ft. The top platens are individually electronically temperature controlled from 150°F-450°F. A nonstick sheet and mounting hardware are provided with each top platen.

Taylor’s 2-sided electric grill sets the time, temperature and platen gap with the touch of a button. Air-cylinder activation automatically lowers the platen to a precise gap measurement. It’s leveled using a solid platform that follows a 3-point reference plane combined with a fixed (home) reference point. Once programmed, the gap resets to the same level every time. Platen surfaces are covered with release material to make cleanup easy. The grill has 3 cooking zones with 3 heating elements on the grill surface and 2 in each platen. Unit dimensions are 40 5/16-in.W x 38 13/16-in.D x 55-60-in.H with platen up.

Vulcan’s new VMCS Clamshell Griddle Accessory, available this month, reduces cook times and increases yield. The unit is constructed of stainless on the front, top and sides and features an anodized-aluminum arm. The cooking surface is 10.4-in.W x 22.9-in.D and the platen is available in grooved steel or Vulcan’s exclusive Rapid Recovery composite griddle plate (aluminum-core interior with 304 stainless exterior) for fast temperature recovery and even heating. A one-hand lift mechanism holds top platen in upright position for ease of loading and unloading.
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