Commercial Fryers: A Buying & Maintenance Guide
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.
Greg McGuire is a regular contributor to The Back Burner, a restaurant news, trends, and marketing blog. He also works for eTundra.com, a company specializing in restaurant equipment, supplies, and equipment parts.