A commercial fryer cooks certain foods extremely efficiently and quickly, and are often used in restaurants and commercial kitchens for appetizers and specific entrees. Fryers use a heating element to superheat an oil medium to around 400 degrees Fahrenheit. When food product is dipped into the oil, the moisture inside boils, but because oil and water don't mix, the product doesn't lose moisture, and it's steamed from the inside out.

The two most common types of commercial fryers are countertop and floor models. The main difference between the two is capacity, and when buying a new fryer, this should be the first factor you consider. Capacity is determined by how many pounds of french fries a fryer can cook in one hour. Typically this is calculated by roughly doubling the oil tank capacity of a fryer. Therefore a 40 gallon fryer should produce between 75 and 80 pounds of french fries per hour.

It's important to calculate the cooking capacity you'll need for your commercial kitchen before purchasing a new fryer. Countertop models have much less capacity than floor models and are typically used for very small volume applications. Larger volume kitchens purchase multiple tank floor fryer units or put several smaller floor units in series next to each other. This is especially useful for frying different food types simultaneously. Avoid flavor transfer from one type of food to another by using the same heating oil.

Gas vs. Electric Fryers

Gas fryers use a natural gas flame either inside a series of tubes that run through the oil or through heating elements located towards the bottom of the oil tank. Gas fryers heat up more quickly than an electric fryer. Gas fryers are also more efficient, though rising natural gas prices has narrowed that gap in recent years.

Electric fryers use an electrical heating element that drops directly into the oil to heat. The primary difference between a gas and an electric fryer is capacity. Electric fryers are small capacity countertop and drop-in models that operate very well when dealing with a small amount of oil (up to about 25 gallons). In this situation, electric fryers are more efficient and recover more quickly.

However, larger capacity fryers, with 40 gallons of heating oil or more, are almost exclusively gas heated units. In a larger capacity context, gas heat is the only way to go in terms of efficiency and heat recovery time.

Types of Fryers

There are three common fryer designs: tube style, open pot, and flat bottom. Almost all fryers are constructed out of heavy gauge stainless steel and include an accurate thermostat for temperature control.

Tube style fryers have a series of tubes that run through the bottom of the heating tank. Gas burners run through these tubes and heat the oil. Tube style fryers also have a cooler sediment area below the tubes. This allows crumbs and food particles to settle out of the super heated oil above the tube burners into the cooler oil below the burners, preventing the carbonization of those particles, which can leave a burned taste on fried foods.

Open pot fryers are heated with either a gas burner or an electric heating element that wraps around the base on the outside of the oil tank. The oil is heated as these elements heat the metal base. Open pot fryers also have a sediment zone below the point where the gas or electric element is heating the oil to allow food particles to escape the super hot oil.

Open pot fryers are typically easier to clean than tube style fryers because the bottom sediment zone is open and reachable. The heating tubes on tube style fryers make cleaning the bottom of the tank more difficult because they sit in the tank above the sediment zone, blocking easy access.

Both open pot and tube style fryers can handle most food products in significant quantities, depending upon the tank capacity of the fryer as discussed above.

Flat bottom fryers do not have a sediment zone that allows food particles to settle out of hot oil. This type of fryer is therefore best for lighter foods that can be bulk fried like tortilla chips and taco shells.

Fryer Maintenance

The heating oil you use in your fryer degrades in quality over time and should be replaced. The frequency with which you need to replace heating oil depends upon what you cook, how much of it you cook and how regularly.

To improve oil quality and lifespan, use a heating oil filtration system to filter out food bits and debris from the fryer. A fryer filter works by draining heating oil from the fryer tank, circulating it through a filter that strains out unwanted particles, and returning the cleaned oil to the fryer tank.

It is also important to boil out fryers regularly to burn fat and carbon buildup off the heating elements and the tank. These deposits can become corrosive and cause severe damage to the fryer. Be sure to clean the inside of the fryer regularly as well, the most logical opportunity for this being when you replace the heating oil.

Make sure you have the proper equipment to handle spent heating oil. Used oil should be stored in stainless steel drums and transported in a spill-proof container with wheels for easy movement. A local biodiesel company will dispose of your used oil for free or even pay you for used heating oil.