Product Knowledge Guide: Fryers

Traditional fryers are powered by gas or electricity and use hot oil to cook food. A pressure fryer cooks food with a combination of hot oil and steam. The choice between gas and electric depends on the utilities that are available and the local cost of gas and electricity.

Foodservice operators can choose between countertop and floor-standing models. Donut fryers feature a shallow cooking depth, while deeper vat units are suitable for cooking product like fries and chicken. Flat-bottom fryers can accommodate floating products, like fish, while larger conveyor units are suitable for production lines, such as in a doughnut shop.

Foodservice equipment manufacturers classify their fryers by tank capacities, which measure the pounds of oil they hold or cooking area size. Fryer vats come in a variety of widths, from 11 to 34 inches and depths of up to 34 inches. A 14-inch fryer can contain between 45 and 50 pounds of shortening, an 18-inch model accommodates between 60 and 100 pounds of shortening and a 20-inch fryer can hold approximately 125 pounds of shortening.

Manufacturers also rate their units based on the number of pounds of french fries and other common fried foods their equipment can prepare in one hour. Generally, fryers produce a volume equal to one and a half to two times the weight of the oil they will hold. Thus, a countertop model with an oil capacity of 15 pounds can produce approximately 28 pounds of fries per hour. High-volume 75-pound units also are available.

Fryers have three basic pot types: open, tube and flat bottom. Open pot designs feature heating elements on the pot's exterior that provide more frying space and easier cleaning. Tube type units carry gas through pipes located inside the pot and have a larger cold zone for use with higher-sediment foods, and square flat-bottom fryers are shallow for use with delicate items.

Today's fryers employ a variety of controllers, ranging from millivolt to computer controllers. Generally the more sophisticated the controls, the more accurate the temperature of the oil. More advanced computer controllers have compensation timing, which accounts for temperature variations and load variations.

Options include analog or computer controllers, lockable casters, wire basket options, and stainless-steel sides and backs. Built-in filtration systems on some models can help extend shortening life and lower shortening cost, in addition to enhancing food quality. A bulk oil system, available from companies other than the fryer manufacturers, can provide new oil and dispose of used oil via piping. This eliminates the need for kitchen staff to transport new and used oil.

Common Applications

  • Fryers are used for deep-fat frying of breaded and unbreaded foods including fries, donuts, poultry, seafood and shellfish.

Specifying Considerations

  • Menu construction will help determine the type and size of fryer the operation requires. If the fried offerings consist mainly of fries and appetizers, then a smaller, 50-pound unit is appropriate. A menu that includes fish, chicken and wings most likely will necessitate a larger 18-inch size. High-volume operations, or restaurants that cook a large amount of bone-in chicken, need a fryer that holds 60 to 125 pounds of shortening.
  • Sites that cook to order may require several smaller fryers as opposed to two or three larger units. A battery of units can include up to six fryers.
  • The types of food being cooked also impact which fryer will work best. Products with heavier sediment, including fresh or heavily breaded foods like onion stacks, typically require a tube fryer.
  • Fries and frozen breaded items are best prepared in an open pot unit. Specialty foods, including fish fillets, shrimp and tortilla chips, work best in a flat-bottom fryer.
  • Pressure fryers and larger capacity fryers with segmented cooking controllers are used for producing bone-in chicken.
  • There are fryers specifically geared toward donut production. These models are very wide and shallow, with a large surface area.
  • Fish fryers, which include flat, nonstick bottoms, also are available in various sizes.

Specifying Mistakes to Avoid

  • Energy efficiency and ease of cleaning can lower total cost of ownership and are areas worth considering.
  • A high-quality oil filter is key to a longer oil life and higher food quality.
  • Open pot fryers are the easiest to clean, but not recommended for specialty products. This type works best with lightly breaded items, like fries and hot wings. Tube-type fryers are more difficult to clean, but work well for heavier frying applications, like fried chicken.
  • Flat-bottom fryers are best-suited for liquid battered foods and bulk frying. These units can be used to prepare tortilla chips and tempura.

New & Notable Features

  • Geared for low-volume operations, newer ventless countertop fryers with two- to three-pound capacities can eliminate the need for costly hoods.
  • Newer gas fryer designs feature heating tubes surrounded by oil to maximize heat absorption.
  • This design forces energy into the oil, with less going unused up the vent. Benefits include quick heat-up time relative to gas consumption, low idle cost per hour during slow periods and low gas consumption per pound of product cooked. Advanced electronic switching devices on some models control power input by modulating the energy amounts to the electronic elements. This provides more precise temperature control and increases reliability.
  • Automated basket lifts are a popular fryer option in high-volume operations, since they can help save labor. Programmable controls provide increased product consistency.On oil-conserving fryer models, automatic replenishment systems sense when oil is depleted and top it off as needed. This provides a consistent oil volume, which enhances food quality. Cabinets can be built into the fryer system, offering additional food warming stations. If a battery of fryers is specified, one filtration system can be used for all units.

When to Replace

  • Increased downtime: When fryers are inoperable on a regular basis, it may be time to purchase a new unit.
  • Rising repair costs: If monthly repair costs exceed the monthly depreciation of a new fryer, consider a replacement.
  • Older unit: The time may be right to replace an older unit. Note that an oil conserving fryer that includes built-in filtration and energy savings would provide a return on investment in less than two years.
  • Temperature inconsistencies: If the fryer does not hold proper oil temperature causing food to be greasy, dark and/or burned, it is time for a new unit.
  • Increase in oil usage and fry time: If weekly oil usage increases dramatically and/or food fry times increase, it signals that a fryer may be ready to be replaced.
  • Leaks: Leaking oil on connections and the interior of fryer controls indicates the fryer has reached the end of its service life.

Maintenance Musts

  • Regularly boil out fryers to eliminate acidic or caustic oil build up on the metal.
  • Change oil when needed.
  • Self-cleaning burner systems perform daily preventative maintenance and keep fryers running at peak efficiency levels.

Environmental Advancements

  • Energy Star-qualified fryers, which are up to 25 percent more energy efficient than standard units, are available in gas and electric models. Under heavy load conditions, these units must meet a minimum cooking efficiency of 50 percent for gas and 80 percent for electric, while also meeting a maximum idle energy rate of 9,000 Btu per hour for gas and 1,000 watts for electric. A low idle rate is key to conserving energy, because fryers are typically in this mode about 80 percent of the time. An efficiency rating of 64.7 or more is preferable.
  • Fryers with the Energy Star designation can save businesses 28 Btu annually, or an average of $185 per year on utility bills, while qualified electric fryers can save 879 kW annually, or an average of $60 per year.
  • Some energy-efficient fryers utilize a blower system powered by an electrical motor that pushes or pulls heat from combustion through the unit. Premix burner systems on other models mix air and gas to maximize energy efficiency.
  • Fryers with an alternative baffling design rely on the natural vacuum in the fryer tank that, through its exhaust, slowly pulls flames through the unit.

Editor's Note: FE&S thanks William Bender, FCSI, of W.H. Bender and Associates for assisting with this article.

Related Articles