Q. I’ve always used olive oil for frying and roasting, but I’ve been told it can be unstable at high temperatures.
A friend recommended rapeseed oil, but I’ve read conflicting advice.
A. Nutrition consultant Juliette Kellow says: "Each oil has its own smoke point (the temperature at which the oil starts to smoke and break down).
This is determined by the natural composition of the oil and how it has been processed.
When this temperature is reached, the quality and nutritional benefits of the oil diminish.
Oils that have had little processing, such as flaxseed, tend to have a lower smoke point so are better suited to little or no heating.
Oils with a high smoke point, such as sunflower, generally have a subtle flavour and are suited to high temperatures.
Like most oils, olive and rapeseed oils can be processed to varying degrees, so can have different smoke points – hence the differing advice you’ve come across.
For example, extra-virgin olive oil is minimally processed so is best for dressings and dips, while refined olive oil is more processed so is suitable for cooking at a high heat.
Check labels for suitable cooking methods.
And, whichever oil you choose, it’s best to make a little go a long way, as 1tbsp contains 100kcal.