Which oil can you fry with? Pick your oil and heat and see
Every cooking oil has a smoke point, the heat where it starts to break down and smoke. Pick how you are cooking and which oil or fat you have, and see whether it is a good fit, borderline or too hot.
The guide explains why published smoke points vary, where the sources disagree (olive and sunflower oil), why you should not keep reusing frying oil, and why every oil still counts as calories.
Which oil can you fry with?
Every oil has a smoke point: the temperature where it starts to give off visible smoke. Past that point the oil is breaking down, it tastes bitter and the kitchen fills with fumes. So the usual advice is simple: match the oil to the heat. But the numbers on the internet disagree wildly, and smoke point is only half the story.
Why the numbers vary
Published smoke points for the same oil can differ by 30 °C or more. Refining raises the smoke point (it strips out the bits that burn first), so a refined oil is the safer pick for hot pans, while virgin and cold-pressed oils keep more flavour and antioxidants but burn sooner. Oil also gets worse every time it is heated: its smoke point falls the longer it cooks and each time you reuse it.
The type of fat matters as well. Oils rich in polyunsaturated fat (sunflower, corn, soya) react most easily with heat. Monounsaturated oils (olive, rapeseed, peanut, avocado) hold up better, and saturated fats (butter, ghee, coconut) are very stable but are not the best everyday choice for your heart. Sources are not fully agreed here: some guidance puts refined sunflower oil among the good frying oils, while the British Heart Foundation suggests keeping polyunsaturated oils to gentler heat, below about 170 °C.
The olive oil question
Is it fine to fry with olive oil? Mostly yes. It is rich in monounsaturated fat, and the research on home frying finds it holds up well. Guidance from the British Nutrition Foundation lists standard olive oil among the oils for frying and roasting, and keeps virgin and cold-pressed oils for dressings and drizzling. Extra virgin olive oil costs more and its flavour fades when hot, so many cooks save it for the finishing drizzle.
Hot pan: a refined oil. Cold salad: a virgin oil. Either way, measure it.
How to use the gauge
Start with the method, not the oil. Pick the heat you actually cook at, then see which oils sit comfortably above it. Ordinary pan-frying and roasting sit around 160–180 °C, and only searing and stir-frying go well above that, so a refined rapeseed or olive oil covers most of what a beginner cooks.
Smoke is a signal
If the oil is smoking, take the pan off the heat, let it cool and start again with fresh oil and a lower flame. Burnt oil tastes bad, and you do not want to breathe the fumes. In a hot kitchen, an extractor fan or an open window helps.
Oil is still calories
Every fat has about 9 kcal per gram, whichever oil it is, so a teaspoon is roughly 40 kcal and a tablespoon roughly 120 kcal. A heart-friendly oil is not a free one. Public health advice is to choose mostly unsaturated oils and use them sparingly, and to check the “saturates” figure on labels. Steaming, baking and grilling need little or no oil at all.
This is general information, not medical advice. If you have high cholesterol, heart disease, diabetes or another condition, take medication, are pregnant or breastfeeding, or have or had an eating disorder, talk to a doctor or dietitian before changing how you eat.
Sources
- British Heart Foundation: Comparing cooking fats
- British Nutrition Foundation: Choose your fats wisely
- World Cancer Research Fund: Best fats and oils for cooking
- Smoke point: table of published values (Wikipedia), which notes that figures vary widely and that oxidative stability predicts cooking behaviour better than smoke point