Foodservice Equipment Reports

Keep That Kettle Singing

For menus requiring volume batches of consistently prepared foods—pastas, rice, eggs, vegetables, stocks, soups, sauces, gravies, barbecue meats and more—steam-jacketed kettles are kitchen essentials. They’re available in a variety of sizes from countertop models to floor versions and they come with an array of capabilities and unique advantages for healthcare facilities.

Steam-jacketed kettles comprise two stainless, pot-shaped containers (sometimes called hemispheres) that fit one inside the other. The space between the two layers is completely sealed and it’s where steam, generated by electric elements, gas heat exchangers or a direct steam feed from a boiler, is introduced. (Note: hot water never touches the bottom or sides of the insert pot, only steam). The concept is similar to a double boiler, but the fact that it’s sealed means pressure can be adjusted to achieve temperatures above 212°F; in fact, you can steam foods to 280°F-300°F with no threat of scorching. (Note: There are units available with thermal fluid in place of steam that can reach temperatures to 360°F.)

Inside the jacket, the pressurized steam in the closed system condenses on the inner hemisphere wall and transfers energy to the food inside. Jackets can cover two-thirds or the entire kettle (known as a full-jacketed kettle), creating significantly more surface area for heat transfer than a stockpot on a burner, for example.

“With some products, you can cut the cooking time in half,” says Mike Williams, product line director, Groen, Jackson, Miss. “You heat up a large volume, but once it is hot, it retains that heat, and your gas and electric usage go way down.”

Signs You Need A Kettle
A steam-jacketed kettle can solve some of the issues that present themselves when you’re using alternatives, such as a stockpot or double boiler on a range top.

Scorched food. In stockpots, food scorches if it’s not minded because cooking temperatures on a stovetop vary, and the heat conducts directly from the burner to pot contents. Contents in the bottom of the pot can burn and sometimes ruin the entire batch of food. Kettles run at highly controlled temperatures, and product heats equally throughout.

Extra labor. Employees constantly have to monitor pots of food on the stovetop, stirring and checking temperatures. Cooks do not need to watch a kettle, so they’re free for other tasks, increasing production efficiency. Lifting hot, heavy stockpots to empty contents into serving or storing containers can be dangerous in a busy kitchen, as well. Kettles tilt in place or feature a draw-off valve to empty contents safely.

Unattended burners. Leaving stockpots on low unattended overnight is not safe for the building or employees and probably violates safety rules. Because kettles prepare foods faster than stovetop methods, staff can produce batches within work-shift hours. Some kettles can be programmed to automatically turn off if the equipment is left alone.

Menu-Driven Decision
With an array of models available, carefully determine your needs and the type of kettle you can accommodate. Size variations, in addition to optional attachments and controls (more on this to follow), differentiate kettles. Kettles come in capacities as small as 1 quart (although rare) up to 200 gallons, so understanding how much food you need to produce and planning for future menu growth will help you choose the best size. Every maker has a sizing/portions chart.

One rule of thumb is that a 40-gallon kettle can produce enough for about 500 portions. Another rule: Four to eight batches of product typically can be made in an eight-hour work shift. By knowing these conversion factors and portion sizes, you can estimate what size kettle will suit your purposes. Manufacturers and their reps also can help with the spec.

Mike Burke, national sales manager, Vulcan, Baltimore, notes that the most common kettles used in the kitchens of healthcare facilities range between six and 12 gallons in capacity and sit on the counter. If you prepare really large quantities (40-gal. and up) of product, a larger floor-mounted model will suit. Many kettles are available with that tilt option to let cooks pour contents into a container. These kettle installations require a floor grate/drain in the pour zone.

It’s a good idea to increase the kettle size if you are contemplating service to multiple locations from one central kitchen or if your facility is planning to expand. At the very least, match your production needs to your bed capacity and the number of visitors and guests that accompany being at full occupancy.

It’s imperative to assess your menu for ingredients, quantities needed and production frequency. Do you have enough production capability to make the food you need when you need it? Single out frozen products: How long do they take to reheat with your current equipment?

You can use kettles for a variety of cooking activities, including poaching, braising, steaming, retherming, sautéing, boiling and blanching.

Burke notes a very important advantage healthcare facilities gain from kettle cooking: the ability to control sodium levels in foods. Low salt intake often is required for patients’ diets. Kettles cook fresh ingredients very well, very fast and in volume and can help you eliminate reliance on pre-made foods preserved with sodium.

If a kettle sounds great, review the other equipment you already have before you buy. Burke advises you consider a kettle if you need to make more than 5 gallons of product at a time. Tight temperature control, slow cooking and the ability to stir ingredients while cooking help cooks execute even delicate preparations, such as tempering chocolate. Unlike a stockpot, the kettle will not use up valuable range-top space.

Surround With Care
Joe Eberwein, v.p. of sales-southeast, Southbend, Fuquay-Varina, N.C., says that one of the most common mistakes operators make when choosing kettles is forgetting space requirements.

Kettles can be mounted on a floor pedestal, countertop or wall. Common sense says that a kettle should be perfectly level and properly secured, but in many locations, local building codes require additional installation rules be met, sometimes according to NSF standards. These might include a specific amount of clearance around the kettle to ensure employees working near the kettle can pass by it safely, and particular distances from other pieces of equipment.

Kettles, of course, need water. In addition to mounted fill faucets, larger kettles are available with water-filler options that will dispense the exact number of gallons you need for each recipe. You may want to use filtered water to cook certain foods.

Steam from kettles is easy to exhaust, which is why kettles are classified as light-duty equipment for ventilation purposes. Make sure your canopy hood or other vents have the correct ventilation rate to meet requirements, about 150-200 cfm per linear feet of hood.

Accessorize, Accessorize
It’s not flashy, but bling for your kettle will take operations to a whole new level of versatility and efficiency.

A variety of supplementary equipment is available, and although items officially are “optional,” experts say some features are must-haves.

A tight-fitting cover is essential to protect against product contamination, contain splashes and retain heat inside the vessel. Draw-off valves, 2-3 in. in diameter, should be installed near the base of the unit to drain water off foods, such as pasta, or empty the actual product into holding containers. Automatic shutoff functions are important for safety and precise cooking times.

Among other add-ons are long utensils to manipulate kettle contents, including stirring paddles and spoons. Chefs can compartmentalize the receptacle by using basket inserts to boil smaller portions of pasta or other solid foods. Mixers adapted for use in kettles have motor-powered agitators that blend ingredients and scrape the kettle sidewalls.

Spurred by employee safety, kettle makers have developed new methods for pouring food from tilting kettles into containers. For floor-model tilt kettles, splash guards and floor troughs catch spills. Some counter-mounted tilt kettles can be placed on top of pull-out container drawers that position perfectly to catch the pour. Pouring lips attach to kettles and help guide food into the container, as well.

Cooks can eyeball exact quantities inside the kettle if gallon markings are etched inside. Manufacturers usually create marks at 1- or 2-gallon increments, but single-gallon marks might be an extra charge—you need to ask.

Shiny Coat, Easy Maintenance
“Steam kettles probably have the least amount of maintenance than any unit you’ll find in a kitchen. You simply need to sanitize the cooking surface after use,” Eberwein says.

Kettles are cleaned in place using long brushes, small amounts of detergent and water.

On the exterior, kettles are available in matte or high-buff polish. The shiny surface costs more, but it’s easier to clean. The only mechanics you need to handle or monitor on a kettle are the power switch and settings dial and the safety valve that displays pressure readings. Keep the tilt mechanisms clean as well. One-year warranties for parts and labor are standard, and longer coverage is available.

“Within a couple of weeks after they start to use their kettle, people realize that it is much easier to do things in a kettle than on a stove,” Burke says. 

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