Filtering fryer oil does more than help cook food — it helps ensure the flavor and quality of fried menu items. Fryer oil filtration systems standardize filtration schedules and remove contaminants.

Best-practice recommendations call for filtering commercial fryer oil at least once a day and more for high-volume operations. Not only can dirty oil negatively impact the taste and texture of food and increase the cost of fryer oil and utility bills, but it also can be dangerous since unfiltered oil can cause fryers to break down or start a grease fire.

Oil that doesn’t get filtered will break down due to the presence of food particles, fatty acids and ice crystals from frozen foods. Its color changes before it thickens and impacts the fryer’s heat transfer and cooking times. Dirty oil requires more frequent changing than regularly filtered oil.

There have been many changes to oil filtration in the past few years, led mainly by an emphasis on safety. Customers now have options from portable filtration to built-in types to hands-free options. These make it simpler and safer to filter oil on a regular basis. Less labor-intensive systems are an alternative to manually filtering oil using a cone filter.

Built-in filtration has become the method of choice the last several years. The biggest benefit is when the filter system is part of the fryer system, the operator is much more likely to filter the oil on a regular basis. Built-in filtration systems are installed within a battery of fryers, often inside the cabinet of a heat-and-dump station.

Using a built-in filtration system might take 5 to 6 minutes total before the fryer is back to the set temperature for cooking product. A longer filter of the oil, or polish of the oil, might take as long as 10 minutes total. The polish process usually occurs at the end of the day, so the oil is fresh and clean for the next day.

In high-volume operations, central filtration systems can help extend shortening life, lower food costs and reduce oil costs by as much as 50%. Some models provide plumbed filtration systems that allow for draining, filtering and returning shortening to the vat. Operators can have central oil filtration and recovery pumped through the kitchen. For these systems, operators must plan for piping to the fryer and for room on the wall to house the hose.

Portable fryer oil filter systems require a bit more labor but are still quicker than manual filtering. Operators can use portable systems with any type of fryer. The process begins by inserting a nozzle into the fry pot, and the system then filters the oil and returns it through the same nozzle.

Portable filtration systems range in size from 50- to 200-pound capacities. These offer different types of filter media, from simple paper to a fabric envelope. This method involves rolling the machine to the fryer, emptying the oil into the filter pan, placing a wand inside the oil pot and turning on the machine. This method allows the operator to wash the sides of the fry pot to get as much sediment into the filter pan as possible.

The latest technology on the market includes hands-free filtration and built-in oil quality sensors. Fryers are an integral part of these systems and include computer controls. With a clean filter pan and filter media in place, the operator can punch a few buttons on the front of the fryer to start the filtering process. The doors can stay closed, and there are no levers and handles to pull. The operator can check the oil quality in real time as well. An oil quality reading displays on the computer control and indicates how much longer until it is time to dispose of the oil.

Several fryer systems also have options for an oil recycling hookup. This allows a third-party oil supplier/recycler to use the pump on the filter system to pump the old oil to a recycling container and haul the oil away.

Fryer filtration monitoring technology equipment can determine when the oil was last filtered, when the oil should be changed and how much oil is being used.

Purchasing Considerations

When purchasing an oil filtration system, remember these are like water filters: They need to be changed and cared for properly to work well.

A general rule of thumb is to allocate one oil filtering system to a fryer bank. Vendors may pipe multiple fryers into one filtration system at the factory, but the system filters only one fryer at a time.

Mobile filtration units can be messy and require a place for storage. Systems that are built into the equipment don’t take up added space. Those who use existing fryers must go with stand-alone systems. These can accommodate any fryer.

Cleaning and Maintenance

Operators can choose among several methods to test fryer oil for quality. Traditionally, the color of the oil is used, with darker colors indicating degraded oil. Fryer oil test strips test for free fatty acids, a by-product consistently produced as cooking oil breaks down. These strips provide alerts about when to filter or change the oil. For a more advanced option, fryers with automatic filters test for total polar materials to determine when filtering or an oil change are needed or can be set to filter on a time-initiated schedule.

Operators must follow a proper sequence when disassembling, cleaning and reassembling oil filtration systems. Sometimes when the unit is disassembled for cleaning, it gets placed on top of a trash can and then forgotten about and thrown away. Parts are hot, so they get dropped and bent, and then they don’t fit correctly. When staff reassembles the unit, sometimes it is not cleaned correctly, and debris gets sucked into the pump. If the order of assembly is wrong, the unit won’t work, and the pump reset trips because it is working too hard. All filter systems have the same order of assembly.

O-rings at the connection of the filter pan to the pump intake will wear out over time and crack. If this happens, the pump will suck air and not the oil. These rings should be replaced at least twice a year.

Operators should never pump water or cleaning solution through a filter system on a fryer. This can ruin a pump very quickly.

A lot of restaurants now use bulk oil delivery and disposal units. Depending on how these are installed, they can create too much pressure on the pumps and cause the seals on the pump to fail. When this happens, oil can leak into the motor and ruin it as well. The built-in filter systems also have different valves with micro switches on them to turn on the pump when the valve is opened and turn off the pump when closed. If the adjustment on these switches is wrong, it can create too much pressure in the pump and cause seal failure as well.