How do I deep fry safely at home?

The rules that prevent the accident, the temperature that produces good results, and what to do if it goes wrong.

Difficulty: intermediate
Time: 40 min
Read: 3 min
Safety: warning

Short answer

Fill the pan no more than a third full, use a thermometer to hold 175-190°C, and dry the food thoroughly before it goes in. Keep a lid or fire blanket within reach and never leave the pan.

Deep frying at home is entirely doable and it is also the single most common cause of serious kitchen fires. Almost every incident traces back to the same three things: too much oil, no temperature control, and an unattended pan.

Safety

Never put water on an oil fire and never move a burning pan. If oil catches fire, turn off the heat if you can reach it safely, get everyone out and call the fire service. Never fill a pan more than a third full, never leave hot oil unattended, and never lower wet or frozen food into it — the water flashes to steam and throws boiling oil out of the pan. If you are unsure, use a thermostatically controlled fryer rather than a pan.

What you'll need

Deep heavy pan or fryer
Cooking thermometer
Oil with a high smoke point
Slotted spoon or spider
Fire blanket
Kitchen paper

Step by step

Use a fryer if you have one.A thermostatically controlled fryer removes the two biggest risks — overheating and overfilling — and is the sensible choice if you fry more than occasionally.
Fill the pan no more than one third.Food displaces oil and it bubbles up considerably. This single rule prevents most overflow fires.
Choose an oil with a high smoke point.Groundnut, sunflower, rapeseed or vegetable oil. Olive oil and butter smoke well below frying temperature.
Heat to 175-190°C and check with a thermometer.Too cool and food absorbs oil and goes greasy. Too hot and it burns outside while raw inside. Guessing is not reliable enough here.
Dry the food completely.Pat it with kitchen paper. Water hitting hot oil turns instantly to steam and throws oil out of the pan violently. Never fry anything frozen unless it says so.
Lower food in gently, away from you.Never drop it. A spider or slotted spoon, lowered in, so any splash goes away from your body.
Fry in small batches.Too much at once crashes the temperature, and food fried in cool oil is greasy. Let the oil recover between batches.
Never leave the pan, and know the fire plan.Unattended pans cause fires. If oil ignites: heat off if safe, do not move the pan, do not use water, get out and call the fire service.
Cool the oil completely before moving it.Hours, not minutes. Carrying a pan of hot oil is how serious burns happen.

Tips

Strain and reuse oil a few times, kept in a sealed container away from light. Discard it once it darkens, smells off or foams.
Do not pour oil down the sink. Cool it, put it in a sealed container and dispose of it with your household waste or at a recycling point.
A pan lid within reach is the best simple safety measure — smothering a small flare-up early prevents almost all serious incidents.

Common mistakes

Filling the pan too full — Food displaces oil and it foams up. Overflow onto a gas flame is the classic route to a chip pan fire.
Frying wet or frozen food — Water flashes to steam instantly and ejects boiling oil from the pan. This causes severe burns.

Questions people ask

What temperature should I deep fry at?

175-190°C for most things. Below that food absorbs oil and goes greasy; above it, the outside burns before the middle cooks.

What do I do if the oil catches fire?

Turn off the heat if you can safely reach it, do not move the pan, never use water, get everyone out and call the fire service. A fire blanket or a lid can smother a small flare-up.