Called a deep-fat fryer because of the amount of oil used, food floats in hot oil with cooking in the top two inches of the fryer. This can lead to a kitchen having a fryer which is too big and heating up more oil than needed.

The industry-wide performance measure of a deep-fat fryer is usually given in weight of chips per hour the fryer can cope with.

Gas or electric power?

There is no clear answer to which is better, both have their own distinctive advantages. The general rule of thumb is that electric fryers are cheaper to buy and suitable for low to medium volume needs. If the kitchen is churning out high volumes of fried product, particularly chips, then gas-powered fryers may be dearer to buy, but are cheaper to run. However, there have been advances in the technology of electric fryers and the operation cost and performance between gas and electric can be negligible. Servicing and instalation costs on gas fryers may be slightly more expensive because of the need to check the gas system.

Good frying practice

A problem common to all gas-fired deep-fat fryers is that the rapid transfer of heat into the oil through a metal wall can lead to oil burn in the base of the fry tank. This happens when food debris falls to the base of the tank and carbonises because of the intense heat. This leads to oil taint and a breakdown of the oil.

The way to get around this used by most manufacturers is a feature called the cool zone. This is normally a sharp depression in the base of the tank which is below the level of the gas burners. Food debris drifts down through the oil and collects in this cool depression, which can often be up to 30 deg C below that of the cooking area of the fry tank. A recent development has been a high-performance flat-bottomed gas fryer without a cool zone.

In a busy operation it makes sense to have at least two deep-fat fryers, once kept exclusively for chips, the other frying anything else.

Electric-powered fryers which have heating elements in the tank have less of a need for a cool zone, but some do still have them on the bigger models.

Oil filtration

With some fryers or small counter-top models, the usual method of oil filtration is the traditional one of a bucket, a sieve with a tea-towel in it and pouring the oil into the bucket through the sieve. This can be both dangerous and inefficient. It is better to buy a freestanding oil filtration system. Either way, oil should be filtered daily.

Some fryers solve the oil filtration issue is using in-built filtration systems. Commonly, the oil is released through the bottom of the tank while still hot through a system of filters and pumped back into the fry tank. The whole process takes between three and five minutes and since the most the operator does is press buttons and open a valve, the safety risks are almost non-existent.

Look after it!

A deep fat fryer is one of the workhorses of the kitchen and has almost no moving parts and has a low maintenance cost. But that does not mean that kitchen staff should not look after it.

The biggest maintenance job of a deep-fat fryer is the cooking oil. Cared for, it will last many sessions without the need for changing. Used carelessly with too high a temperature, a failure to clean and filter food debris at the end of every kitchen session and oil can be degraded within a couple of days.

Oil is a hardy material but even this and everything it touches will need cleaning. The oil tempartures vary greatly from rest temps to cooking temps. Its when oil solidifies building up on any contact surfaces and the basket itself. A strict cleaning regime including degreasing within the fry tank will ensure that your fryer runs well without the need for engineers to come and correct failures because of a poor cleaning schedule.

It is an engineer’s job to ensure that any item of equipment serviced is left in a clean condition as well as a good working condition. If the deep-fat fryer has been allowed to become very dirty with a high build-up of congealed oil on the casing, the engineer may well remove it, but this is going to reflect in the cost of servicing. Far Better that a member of the kitchen staff do the cleaning before the service engineer arrives.

But do not allow kitchen staff to use abrasive scrubbers or powders on control dials which could eventually remove the dial setting marks and bring about the need for a replacement dial.