There are two broad ways to filter fryer oil. Passive methods (screens, cloth, paper, cones, filter plates) sieve out crumbs and particles. Active methods also reduce some dissolved compounds that sieving cannot catch. For most Singapore restaurants, caterers and food manufacturers, a daily passive filter, done safely on cooled oil, is the practical base. The fryer you buy decides how easy that routine is, and our fryer range is built for commercial kitchens that run it every day.
This guide sets out each method, how to filter oil step by step, which method suits which kitchen, and what Singapore’s agencies expect around hot oil and used oil.
TL;DR
- Passive filtration (screens, paper, cones, cloth, filter plates) removes particles. Active filtration also reduces certain dissolved compounds in the oil.
- Never drain oil above 40°C. Switch off, isolate the power and let the oil cool, ideally for at least six hours.
- Filtering extends oil life and can cut oil use, energy use and cleaning time, but it does not replace discarding oil that has darkened, smells, smokes or foams.
- Choose the method by the number of fryers, the volume of oil and how much breaded or battered food you fry.
- Used cooking oil in Singapore must go to a licensed general waste collector, and your grease trap needs regular servicing.
Table of Contents
- Why filter fryer oil at all
- The main fryer filtration methods
- Comparison at a glance
- How to filter fryer oil safely, step by step
- When to filter and when to discard
- Which method suits your kitchen
- Where the oil goes next
- Saving oil and energy over a year
- Our view on filtration and fryer choice
- Choosing your fryer with filtration in mind
- FAQ
- Sources
Why filter fryer oil at all
Every batch leaves crumbs, flour, sugar and fragments of batter in the oil. These burn at frying temperature, darken the oil and speed up its breakdown. The Singapore Food Agency (SFA) states that repeatedly heated oil can form potentially harmful compounds, including aldehydes and polycyclic aromatic hydrocarbons. Its 2024 guidance recommends replacing oil frequently and straining used oil through a cloth or sieve before reuse.
For a business, the commercial case follows from the same point. The Institute of Food Technologists (IFT) notes that filtration may improve food quality, reduce oil use, energy use and cleanup time, and extend oil life. Cleaner oil also means the fryer holds its set temperature with less strain, which matters for kitchens trying to bring electricity bills down.
Filtering is a tool for keeping oil in good condition for longer. It does not make oil last indefinitely. The signs that oil is finished are covered below.
The main fryer filtration methods
IFT groups commercial systems into two types. Passive systems sieve out particulates, while active systems also remove or reduce specific oil-soluble chemical compounds. The passive group includes metal screens, indexing paper, paper cones, plastic cloths, plate-and-frame, diatomaceous-earth and leaf-filter systems.
Skimming and metal screens
This is the first line of defence in every kitchen. A skimmer or fine mesh basket removes floating crumbs during service. Crumbs left in hot oil burn and darken it, so frequent removal is advised. The Hong Kong Centre for Food Safety recommends frequent removal of crumbs and residues and frying at 150 to 180°C. The same guidance suggests 120 to 130°C during idle periods.
Skimming costs almost nothing and takes seconds. It does not remove the fine sediment that settles at the bottom, so it works alongside a daily filter, not in place of one.
Cloth or sieve straining
This is the method SFA names for reusing oil: strain the cooled oil through a clean cloth or sieve into a container before it goes back to the fryer. It suits small operations, stalls, small caterers and kitchens with one or two small fryers.
The points to manage are:
- Let the oil cool first (see the safe procedure below).
- Use a clean cloth or sieve for each session.
- Pour in small batches so nothing overflows.
- Store reused oil sealed and away from light, as SFA recommends.
Paper and cone filters
Filter paper or a paper cone sits in a holder over a container. Oil passes through by gravity or with a pump and the paper traps fine particles. Websites in this field often quote filtration down to a few microns (a micron is one thousandth of a millimetre), though the figure depends on the paper and the equipment. Paper and cone filters fit kitchens that fry breaded items daily, because they catch finer debris than a sieve.
They use consumables, so build the cost of paper into the routine. Replace the paper when it clogs or when oil runs through slowly. Oil is thicker when cooler and filters more slowly, which tempts staff to filter too hot. Do not do that.
Filter plates, leaf filters and diatomaceous earth
These are the heavier industrial passive systems. They push oil through plates or leaves, sometimes coated with diatomaceous earth (a fine powder made from fossilised algae), to catch very small particles. They are found in food factories with large continuous frying lines and high oil volumes. For a restaurant or catering kitchen they are generally more than the job needs.
Active filtration
Active systems use filter media to reduce specific dissolved compounds as well as particles. Among the concerns IFT lists for the technology are leaching, equipment, legal issues, costs and safety. These are mainly a consideration for high-volume operations that fry the same product for long hours. Food manufacturers weighing them should check the media supplier’s instructions and any applicable food regulations.
Built-in and portable filtration units
Beyond the filter medium, there is the question of how oil moves. In a built-in system the fryer pumps oil through a filter and returns it, so staff handle little hot oil. A portable unit is wheeled to the fryer and does the same job for several fryers.
The Health and Safety Executive (HSE) in the United Kingdom notes that automated or semi-automated enclosed systems substantially reduce contact with hot oil. The reduced contact with hot oil is the main safety argument for enclosed systems. HSE guidance is British, but the physics of hot oil is the same in Singapore.
Comparison at a glance
| Method | Removes | Best for | Staff handling of hot oil | Running cost |
|---|---|---|---|---|
| Skimmer or mesh | Floating crumbs | Every kitchen, during service | None | Very low |
| Cloth or sieve | Visible particles | Small kitchens, stalls | Pouring cooled oil | Low |
| Paper or cone | Fine sediment | Daily frying of breaded or battered food | Moderate | Paper consumables |
| Pump and paper unit | Fine sediment | Several fryers, busy service | Lower | Paper and maintenance |
| Plates, leaf, diatomaceous earth | Very fine particles | Factory frying lines | Low (enclosed) | Media and equipment |
| Active media | Particles and some dissolved compounds | High-volume continuous frying | Low | Media and equipment |
How to filter fryer oil safely, step by step
The sequence below follows HSE’s catering guidance on emptying and cleaning fryers, with the SFA and Hong Kong points added. Always follow your fryer and filter manufacturer’s instructions where they differ.
- Switch off and isolate. Turn the fryer off and isolate the electric power at the wall. For a gas model, turn off the gas supply.
- Cool the oil. HSE advises cooling the oil ideally for at least six hours and checking it with a probe thermometer. Do not drain oil above 40°C. For this reason many kitchens filter at the end of the night’s service and leave the oil to cool overnight.
- Prepare the container. Use a suitable covered metal or heat-resistant rigid plastic container. Place it on a drip tray, away from water and chemicals.
- Use smaller batches for large volumes. A full 20-litre tank is heavy. Split it into smaller loads to avoid lifting injuries and spills.
- Filter. Pass the oil through your chosen medium: sieve, cloth, paper or the unit’s filter.
- Clean the tank. Remove sediment from the base and walls. Take care with cleaning chemicals. HSE lists the hazards of this task as fire, hot-oil burns, chemical fumes, overflowing cleaning chemicals, eye injuries, slips and strains from lifting.
- Refill and check. Return the filtered oil, top up with fresh oil if needed, and bring the fryer back to temperature.
- Clean spills at once. A greasy floor is a slip hazard in a busy kitchen.
Wear the personal protective equipment your risk assessment calls for. HSE names eye protection, protective aprons and heat-resistant gloves where splash or hot-surface risks remain.
Many kitchens ask whether oil can be filtered while hot. Some industrial lines filter at process temperature, using enclosed equipment designed for it. In a manual restaurant routine, follow the 40°C limit when draining by hand. Hot-oil burns are one of the most common serious injuries in kitchens.
Our deep fryer maintenance routine covers the daily and weekly cleaning that goes with filtering.
When to filter and when to discard
Filter on a schedule that suits your menu. Kitchens that fry breaded chicken, tempura or fish usually filter at least daily, because batter debris builds quickly. Kitchens frying plain chips may filter less often.
Filtering will not rescue oil that has broken down. SFA says to replace oil when it changes colour, develops an unusual odour, begins smoking or starts foaming. The Hong Kong Centre for Food Safety adds that it can be hard to set oil changes by a fixed number of days or uses, because deterioration depends on the food fried and the frying temperature. Judge the oil by its condition and keep a log of what you fry and when you change oil.
Reused oil should be kept sealed and out of light. Maintaining the right frying temperature and removing residues matters as much as the filter. Checking oil condition instead of relying on a fixed reuse schedule is the same principle that drives sensible grease trap servicing.
Which method suits your kitchen
The right method depends on three things: how many fryers you run, how much oil each holds, and what you fry.
One or two small fryers
A stall, small caf or start-up with an 8 to 12-litre tank can combine skimming with cloth or paper straining at the end of the day. A compact model such as our 8L deep fryer, electric single deep fryer 10L or electric single deep fryer 12L holds a volume that one person can cool and strain in a single sitting.
Busy restaurants and caterers with double tanks
A double-tank fryer holds more oil and runs longer. Filtering twice the volume by hand takes more time and more handling of containers. Here, the safe split-batch method in the steps above matters, as does choosing a fryer design that keeps handling to a minimum. Our standing double deep fryer suits this kind of kitchen. The automated standing double deep fryer is for kitchens that want a more automated workflow.
Gas or electric
Your fuel type affects how you drain and clean. Our guide to gas versus electric fryers in Singapore kitchens explains the fitting and running differences before you buy. A 14L gas deep fryer follows the same cooling and draining rules, with the gas supply shut off first.
Food manufacturers
Factories frying at volume for hours need continuous or enclosed filtration, such as plate or leaf systems. The oil volume, the product and the allergens carried over from one product to another shape the choice. Follow the equipment maker’s instructions and your food safety plan.
Where the oil goes next
Filtering delays disposal. It does not remove it. Singapore has specific rules for what happens to used oil and the grease that reaches your drains.
- Grease traps. The national water agency PUB requires grease traps for food establishments, including restaurants, coffee shops and hawker centres. It recommends maintenance at least once every two weeks by a licensed general waste collector, and more often where the fats, oil and grease load is higher.
- Handling. PUB says greasy waste collection and disposal should only be handled by a licensed general waste collector. Never pour filtered or spent oil down a sink.
- Collector licence. The GoBusiness directory states that a general waste collector licence is required for a company collecting or transporting used cooking oil from any food establishment. Check that your collector holds one.
- Classification. The National Environment Agency’s 2024 code identifies used cooking oil as Class B.1 waste, to be taken by licensed collectors to a licensed facility. It also requires spill-control equipment and prohibits spilling or discharging used cooking oil in public places.
Keep a record of each collection with the collector’s name and date. It shows an inspector that your oil is handled correctly.
Saving oil and energy over a year
Filtering is one part of a wider oil-cost routine. Fry at the temperature your recipe needs and no hotter. Remove crumbs often. Lower the set point in idle periods, as the Hong Kong guidance suggests. Keep lids on and oil sealed. Our guide to reducing fryer oil costs in Singapore kitchens sets out these operating routines in more detail.
Equipment matters too. Newer energy-efficient commercial equipment can qualify for government grants in Singapore. Check the current scheme rules with the relevant agency before you buy, since eligibility and support levels change.
Our view on filtration and fryer choice
We speak with restaurant owners, caterers and food manufacturers who want lower running costs. Oil and electricity are two of the largest lines they can control in a fryer kitchen.
Filtration is a daily habit, and daily habits depend on the equipment. A fryer that is simple to cool, drain and clean gets maintained. One that is awkward does not. That is why we match fryer size and type to the kitchen: a compact tank for a start-up, a double tank for a busy line, an automated model for a team that wants less handling.
We focus on energy-efficient commercial kitchen equipment and on guidance for claiming government energy efficiency grants. Our showroom lets you see the fryers in person and talk through your menu, volumes and layout before you decide.
David
Choosing your fryer with filtration in mind
If you are setting up a new kitchen or replacing a fryer, decide your filtration routine first, then pick the fryer to suit it. Our fryer range covers single and double tanks, in electric and gas. Browse the full commercial kitchen equipment collections online, or visit our showroom to see the models and discuss grant eligibility for energy-efficient equipment.
FAQ
How do I filter fryer oil at the end of the day?
Switch off and isolate the power, then let the oil cool. HSE advises ideally six hours and never draining above 40°C. Strain it through a clean sieve, cloth or filter paper into a covered metal or heat-resistant container, clean the tank, and return the oil.
How often should fryer oil be filtered?
Kitchens frying battered or breaded food usually filter daily. Others can filter less often. Replace oil when it darkens, smells unusual, smokes or foams, as SFA advises. Condition, not a fixed number of days, is the better guide.
Can I filter fryer oil while it is hot?
By hand, no. Cool it below 40°C before draining. Industrial lines use enclosed equipment built for filtering at process temperature, and these follow the manufacturer’s instructions. Enclosed systems reduce contact with hot oil.
What happens to oil I can no longer use?
It must be collected by a licensed general waste collector. In Singapore, used cooking oil is Class B.1 waste and goes to a licensed facility. Never pour it down a drain. Keep your grease trap serviced at least every two weeks, as PUB recommends.
Sources
- Ensuring Quality and Safety in Fried Foods, IFT
- Catering Information Sheet No 17, HSE
- Reusing Cooking Oils, SFA
- Tips for Using Deep-frying Oil, Centre for Food Safety, Hong Kong
- Grease Trap, PUB
- General Waste Collector Licence, GoBusiness
- Code of Practice for General Waste Collectors, NEA